Showing papers in "Behaviour in 1978"
TL;DR: A factorial design demonstrated that the female Norway rat has the major role determining the amount and timing of copulation once mating begins, and the population pattern of a wild female was characterized by fewer ejaculatory series and more intromissions at longer intervals before the first ejaculation than the patterns of a domestic female.
Abstract: The copulatory behavior of both wild and domestic strains of Rattus norvegicus was observed via continuous video monitoring as it spontaneously occurred in the large seminatural environment and under standard laboratory conditions. A factorial design demonstrated that the female Norway rat has the major role determining the amount and timing of copulation once mating begins. Copulation between wild pairs was characterized by fewer ejaculatory series than domestic pairs. The first ejaculatory series of wild pairs contained more intromissions at longer intervals. Domestic pairs had the same total number of intromissions in a copulatory session, but spread over multiple ejaculatory series with few intromissions at short intervals in the first series. The characteristic differences between the copulatory patterns of wild and domestic pairs was determined by the female's strain condition and was either statistically independent or opposite to the male's strain condition. Specifically, the population pattern of a wild female was characterized by fewer ejaculatory series and more intromissions at longer intervals before the first ejaculation than the pattern of a domestic female. These differences between wild and domestic populations were produced by differences in the rate of active solicitations for an intromission by individual females : the solicitation occurred virtually in a one-to-one correspondence with an intromission. There were no gross anatomical differences between the vaginal size and placement of the two strains. The female solicitation is a distinct and quantifiable behavior not found in the standard testing cage: its occurrence depends on a larger and more complex environment. In addition, copulation in the larger seminatural environment is characterized by fewer intromissions in each ejaculatory series of a session at longer copulatory intervals. The role of the female is discussed both in terms of the individual interactions which underlie it and in terms of its physiological functions for successful reproduction in the rat. Copulation with a wild male is characterized by longer intervals between the intromissions of the first ejaculatory series than with a domestic male. The wild condition of both the pair and the female showed the opposite effect. This difference is evaluated in terms of the different mating strategies for the two sexes on a population level and in terms of the individual interactions that allow a compromise for successful reproduction of the pair.
231 citations
TL;DR: Differences between the species in the tempo and length of fights were observed, and an hypothesis, based upon habitat differences and the value of burrows as a resource, is presented to account for these differences.
Abstract: The aggressive behavior of two temperate species of fiddler crabs (Uca pugilator and U. pugnax) was studied in the field. Most of the fights wer between Residents (crabs owning burrows) and Wanderers seeking to displace them, though less commonly, fighting occurred between Residents occupying adjacent burrows. Over 400 fights were observed in each species. The two species showed differences in the sequences of acts performed during fights. Uca pugnax also performed two acts never observed in U. pugilator. Wanderers were rarely successful in displacing Residents of the same size or larger, but they won a small percentage of fights when they were larger than the Resident. Uca pugilator Wanderers select Residents that are slightly smaller, but we found no evidence for size selection in U. pugnax. Strongly motivated Wanderers repeatedly performed a key act (Downpush), which was also strongly correlated with successfully displacing Residents. Combat duration and number of acts were not related to temperature, the time of day, or the time in relation to low tide. However, the incidence of fighting increases in the early afternoon. Most of the fights occur within 1-3 hours after low tide. Differences between the species in the tempo and length of fights were observed. An hypothesis, based upon habitat differences and the value of burrows as a resource, is presented to account for these differences. We compared our data to CRANE'S (1967) for U. rapax, a tropical species. There are some important differences between her findings and ours, even though U. pugnax is closely related to U. rapax. We suggest that at least one of her opinions on the significance of aggression in tropical fiddlers is in conflict with evolutionary theory. Some of her other ideas do not apply to temperate species, where climatic factors may be responsible for behavioral convergence. Our data also indicate that the differences and similarities between species are sufficiently provocative to warrant further comparative studies.
181 citations
TL;DR: The breeding behavior of threespine sticklebacks from Wapato Lake, Washington, U.S.A., was investigated using the ethological approach and a male's level of aggression, body color, boldness toward predators, nest concealment behavior, and egg stealing behavior changed during his reproductive cycle.
Abstract: The breeding behavior of threespine sticklebacks from Wapato Lake, Washington, U.S.A., was investigated using the ethological approach. Much of the breeding effort of males was synchronized and there were 3 peaks of abundance during the 100 day period of major breeding. In June, a male's cycle lasted 13 to 14 days during which an average male collected 1000 eggs from about 10 females. Superior reproductive success of males was associated with nesting early in the season, in vegetated littoral areas of the lake, in deep water, and in shelter habitat. A male's level of aggression, body color, boldness toward predators, nest concealment behavior, and egg stealing behavior changed during his reproductive cycle. The changes in body color and behavior seemed related to a decreasing emphasis on stealing eggs from a rival's nest and an increasing emphasis on parental care. Most nest offspring were cannibalised within 2 days after fertilization. Neighboring males in all stages of breeding used solitary sneaking behavior to steal eggs from a rival's nest and most eggs were stolen by parental males. Raider packs, composed of hundreds of non-breeding male and female adults, also raided nests causing a total loss of the nest and its contents. Raiding of nests by breeding males seemed related to a shortage of food resources. Females often courted males prior to spawning. The incidence of this behavior seemed related to an excess of females.
164 citations
TL;DR: The jackdaws prefer to feed where a subordinate bird is present, avoid feeding with a dominant and seek interactions with individuals with whom the outcome of the interaction is rather unpredictable, which shows that the population is able to sustain itself.
Abstract: Jackdaws are highly social corvids. They feed in flocks, roost communally and often breed in colonies, using natural holes as nest-sites. This study describes and investigates the social organisation of jackdaws. Particular attention is payed to the functional aspects of their social organisation. The study was carried out from 1071 to 1976 in and around the village of Haren in the north of the Netherlands. Most of the jackdaws nest singly in chimneys which are scattered over the area. A small colony was created by hanging nesthoxes (15-25) on the walls of the Zoological Laboratory in Haren. It was here that most of the data were obtained. Over 600 birds were colour-banded for individual recognition. Within the population two social categories can be distinguished : resident and non-resident birds. The former defend one or more nest-sites throughout the year (except in summer). The latter defend one nest-site, only during the breeding season, if they are successful in obtaining one at all. Only adult and mated birds belong to the resident category whereas non-residents are of all ages, mated and non-mated. These categories are not static. Non-residents become residents and vice versa. Furthermore, the distinction between residents and non-residents appears to be more conspicuous in colonially nesting birds than in solitary nesting ones. In the study area 80% of the adult colour-banded birds, present in any one year, was resighted the follow-ing year. Only 48% of the first year birds was resighted again in the study area. Reproduction was approximately I young per pair per year. These figures show that the population is able to sustain itself. Estimations from other methods all suggest a much higher mortality rate. Some of these require an unrealistically high reproduction to prevent the population from declining to extinction. Some factors which may bias mortality estimations are discussed. Jackdaws are monogamous and mates remain together, both throughout the year and from year to year. Adult jackdaws are very unlikely to remate unless their mate dies. In contrast, newly mated, juvenile birds, readily change mates. However, the probability of divorce is not increased by an unsuccessful breeding attempt. Males and females react differently after losing their niate. Males try to retain their nest-site. As a result of the aggression by mated pairs, single males are seldom successful in maintaining nest-site ownership for long, but while they do, they appear to be very attractive to non-mated females. Females desert their nest-site and start to court mated (or non-mated) males possessing a nest-site. Non-mated females can gain much by seducing mated males but they seldom succeed. Jackdaws produce only one clutch per year. Resident pairs are more successful in breeding than non-resident pairs. This difference is affected by various factors, including nest-site quality, age, time of egg-laying and intraspecific interference in breeding. Pairs which failed to raise young often start to inspect other nest-sites thus harassing more successful pairs. Among the resident members of the colony a well developed, site independent rank-order was found. Males dominate females. The rank of the female depends on the presence and rank of her mate. Different dominance criteria produce different rank-orders. By allowing the birds to choose who to compete with over food, the connections between rank relationships and social preferences have been analysed. The jackdaws prefer to feed where a subordinate bird is present, avoid feeding with a dominant and seek interactions with individuals with whom the outcome of the interaction is rather unpredictable. Shifts in rank are most common during the breeding season. Unsuccessful breeders often rise in rank at the expense of successful ones. Feeding flocks are open groups with individuals and parties joining or leaving. However, resident members of a colony often feed together and form a rather stable core of many flocks, particularly in the vicinity of their colony. Flock sizes and feeding ranges vary seasonally. During the breeding season both are much smaller than during summer and winter. High ranking colony member have somewhat smaller feeding ranges than low ranking ones throughout the year, suggesting that the latter are forced to feed at larger distances. This is, however, still poorly understood. By feeding in flocks the jackdaws are able to withstand the attacks by territorial carrion crows. There are indications that the presence of crows and the vigour of their territorial defence, contribute to the flocking tendency in jackdaws. Flock feeding also increases the feeding efficiency of individual flock members by intraspecific social learning of new food sources. Birds which are familiar to one another are more likely to copy each other than are unfamiliar birds. The difference appears to be largely due to the fact that the jackdaws readily supplant a familiar bird engaged in exploiting a new food source, provided it is inferior in rank. By supplanting the birds apparently bring themselves into the right situation to copy the behaviour of another individual. The daily activities of resident pairs are centered around their nest-sites during most of the year. They defend one or more nest-sites and visit several others daily from early fall on. Both by defending more nest-sites and by visiting others, the jackdaws remain Informed of alternatives should their own nest-site become unavailable or unsuitable for breeding. High rank, the number of defended nest-sites and priority of access to nest-sites in short supply, are correlated. Hole nesting not only protects the nest's contents against most predation, it also renders it possible for jackdaws to nest inside the territories of the interspecifically aggressive carrion crow. Colonial nesting appears to give no additional protection against nest predation under most conditions. Moreover, communal defence against nest predators is practically absent and so far there are no indications that jackdaws prefer to nest colonially. Field studies of social systems have produced a growing awareness of the fact that characters of behaviour, morphology, demography and social structure are not independent but form an adaptive complex. Some of the relationships between these characters in the jackdaw are discussed. Finally, environmental factor, such as predation, the availahility of food and interspecific competition, tnould each of these characters and their relationships. In jackdaws the chief benefit of flock feeding and hole nesting seems to be that thus the jackdaws are able to withstand the interspecific aggression of the territorial carrion crow.
147 citations
TL;DR: In this paper, the authors describe the pattern of parental investment in the pink-footed goose (Anser brachyrhynchus) during the fledging period in Iceland, concentrating particularly on the analysis of vigilant behaviour as one important element of parental care.
Abstract: In this study we describe the pattern of parental investment in the pink-footed goose (Anser brachyrhynchus) during the fledging period in Iceland, concentrating particularly on the analysis of vigilant behaviour as one important element of parental care. We quantify parental investment, and its cost to the parent, by comparing the behaviour of parents with that of 'pairs' of adults without young (most of which are probably failed breeders). Each partner's strategy of investment is not expected to be purely selfish in this long-term pair-bonding species, and the sex differences in parental care are examined in this light. The time budgets of parents and pairs differed, parents walking more, grazing more and preening less. Parents also spent more time in the extreme head up posture and less in the head low and head on back postures than pairs but time devoted to the head up posture was the same for both. Brood size had no effect on the time budget. Time spent extreme head up declined over the study period in parents but not in pairs. Spacing patterns and behaviour varied independently in non-breeding birds but families sat closer to other geese when the vigilance level of the parents was low (i.e. in the head on back or head low postures) than when it was high (the head up or extreme head up postures). All agonistic encounters between parents and non-breeders were both initiated and won by the parents. Tied encounters occurred between birds of equivalent status in terms of brood size or non-breeding group size. The potential sources of parental care are summarized (Table 6) and, after considering the evidence for each, it is concluded that (apart from brooding) two types of parental investment are made by parents: (1) enhancement of offspring feeding efficiency by reducing competition through agonistic behaviour, and perhaps avoidance; and (2) protection from predators by (a) active defence, (b) seeking proximity with other geese when resting, and (c) visual scanning for predators (mainly by the male) using the extreme head up posture. Parents paid for this investment by devoting less time to preening and sleeping. The male's investment in predator vigilance was made at the cost of a reduced feeding time and to compensate for this he pecked at a faster rate than his mate. These sex differences are explicable in terms of earlier differences during incubation. The adoption of unrelated goslings was observed and the implications of the phenomenon are discussed. For individuals in non-breeding groups the time spent extreme head up declined as group size increased. The functional significance of this finding is discussed and it is concluded that in sitting groups extreme head up is probably used to scan for predators.
140 citations
TL;DR: Data suggest that male-female relationships are best understood not by examining sexual consortship alone but by considering sexual behaviour within the context of social interactions throughout all reproductive states.
Abstract: A study of social interactions between two adult males and eight adult females throughout sexual cycling, pregnancy, and lactation revealed three types of "long-term" social bond. 1. Persistent, high-frequency bonds. Two male-female dyads exhibited frequent proximity and grooming throughout the study regardless of changes in female reproductive state. In both cases frequent interaction persisted because of preferences which partners showed for each other. Males in both dyads aided their partners when the partners received aggression more often than they aided others. 2. Persistent, low-frequency bonds. Three females showed a preference for the Alpha male over the subordinate male in all reproductive states. Each female appeared to be attempting to establish a "high-frequency" social bond with the Alpha male. However, all were prevented from doing so by two factors: the Alpha male's preference for one female over all others (see above), and competition from this preferred female. Females competed for access to the Alpha male equally often in all reproductive states. 3. Bonds based on "alternating" f emale preference. Three females associated primarily with the subordinate male during lactation and the Alpha male during sexual cycling. Since the subordinate male served as a focal point for the activities of infants and juveniles, females appeared to benefit from their association with him during lactation. In addition, data suggested that the subordinate male, having established bonds during lactation, attempted to maintain these bonds into the females' periods of sexual cycling. It is hypothesized that the existence of these male-female bonds in multi-male primate groups produces a social structure characterized by a polygynous mating system. Data suggest that male-female relationships are best understood not by examining sexual consortship alone but by considering sexual behaviour within the context of social interactions throughout all reproductive states.
132 citations
TL;DR: Although rates of female-female aggression were not affected by the formation of sexual consortship, adult females were more likely both to ignore threats from higher-ranking individuals and to be supported by adult males during sexual Consortship than at other times.
Abstract: 1. During 15 months' observation of a troop of free-ranging baboons, 13 of 16 female sexual cycles included a period of sexual consortship. Sexual consortships were defined in terms of both frequent proximity and exclusive sexual interaction between partners. 2. Female preference, male preference, and female rank were all important in determining the frequency with which specific individuals formed sexual consortships. The Alpha male was preferred by 7 of the 8 adult females, and, as a result, was involved in 10 of the 13 sexual consortships. The subordinate male formed sexual consortships twice when 2 females were swollen simultaneously and once when a female preferred him over the Alpha male. In the former two cases the higher-ranking female consorted with the Alpha male and the lower-ranking female with the subordinate male. In the latter case the Alpha male did not interfere with the subordinate male's sexual consortship. As an indication of male preference, on one occasion both the Alpha and the subordinate male ignored the presents of a fully swollen female, even though she was the only sexually receptive female in the troop at the time. 3. Sexual consortships were formed from 1 to 14 days after the female had become fully swollen, and invariably ended at least one full day before the onset of deturgescence. Sexual consortships ranged in length from 1 to 8 days, with a mean length of 3.5 days. "Successful" sexual consortships (i.e. those which resulted in conception) were more likely than others to be in progress on cycle days D-7, D-6, and D-5. 4. In the days preceding sexual consortship, females were more important than males for both the maintenance of proximity and the initiation of mounts. In contrast, during sexual consortship males were more important for the maintenance of proximity, while females were relatively less responsible for the initiation of mounts. 5. During sexual consortship partners maintained a generally higher rate of mounts with insertion that at other times, and their mounts with insertion were more "clumped" in time. There was no indication, however, of any peak in sexual activity relative to a particular day before the onset of deturgescence. 6. The formation of a sexual consortship did not appear to interrupt a female's social interactions with other animals in the troop. In most cases, however, proximity between females and their offspring increased during the period immediately after consortship had ended. 7. Although rates of female-female aggression were not affected by the formation of sexual consortship, adult females were more likely both to ignore threats from higher-ranking individuals and to be supported by adult males during sexual consortship than at other times.
126 citations
TL;DR: The social differentiation in small groups of captive female hamadryas baboons was examined and it was demonstrated that the influence of the sum of ranks and of mutual attraction were nearly independent.
Abstract: The social differentiation in small groups of captive female hamadryas baboons was examined. Two positions could be distinguished: The highest ranking female, denoted as central individual, monopolized nearly all the presenting, mounting and grooming interactions. The lower ranking females, denoted as peripheral individuals, competed for access to the central female. All dyads of a group were arranged in a rank order according to the amount of sociopositive interaction which they reached within the group. This order of prevalence of dyads was positively correlated with the sum of dominance ranks of the dyad and the mutual attraction as estimated by choice tests. A multiple rank correlation demonstrated that the influence of the sum of ranks and of mutual attraction were nearly independent. If an individual's relationship to the central female had a higher rank of prevalence than that of its rival, it intervened more often and more successfully when the rival tried to interact with the central female. Interventions served to defend rather than to establish relationships. The results are compared with other studies that discuss basic principles governing structuring processes in nonhuman primate groups.
120 citations
TL;DR: In this paper, the behaviour of 28 domestic cats from the 4th to the 12th weeks after birth was studied in the presence and absence of their mother, and measures of distress, activity, timidity, distance between mother and kitten, and seven facets of play were obtained.
Abstract: The behaviour of 28 domestic cats from the 4th to the 12th weeks after birth was studied in the presence and absence of their mother. We obtained measures of distress, activity, timidity, distance between mother and kitten, and seven facets of play. The developmental trends in the various measures of play were different, some categories declining in frequency from the 4-7 week period to the 8-12 week period and others notably Object Contact, increasing markedly. These opposing trends and a marked lack of correlation between the measures of play suggest that the outputs of several independent systems are commonly lumped under the general heading of play. The measures of more general aspects of behaviour did not show analogous trends to any of the measures of play and were not correlated with any of them. Cat Contacts in the 4-7 week period was a strong predictor of the same measure in the 8-12 week period. However, none of the other correlations between play in the two age periods is statistically significant, emphasising the marked developmental discontinuity, shown particularly in Object Contacts, between seven and eight weeks after birth. Males made significantly more Object Contacts than females in the 8-12 week period. However, this difference was much less marked when the females had a male in the litter.
115 citations
TL;DR: Songs of Splendid Sunbirds at Cape Coast University, Ghana, were recorded and the audiospectrograms analyzed by multivariate statistical techniques, finding similarities among the songs of neighboring birds, differences between neighborhoods, and the uniform size of the song "dialects" are tentatively explained in terms of social adaptation rather than habitat adaptation.
Abstract: Songs of Splendid Sunbirds at Cape Coast University, Ghana, were recorded and the audiospectrograms analyzed by multivariate statistical techniques. Neighboring birds usually had similar but nonidentical songs. Groups and subgroups of neighbors occurred at distances up to 7 km. Several birds had songs intermediate in structure between those of the main groups, and a few had songs unlike their neighbors. Song differences measured by phenetic distances are significantly correlated with microgeographic distances between the birds, at distances up to 1-2 km. The variation in song is described in terms of dialects and in terms of behavioral variation with microgeographic distance. The dialect areas were less than 1 km2 and involved from 5 (probably an underestimate) to 14 individual males. The local microgeographic scale of song variation agrees with that reported for other populations in Ghana, but variation in space is not as grouped into discrete dialects as described by GRIMES (1974). Birds with similar songs did not consistently occur in similar habitats, except when the birds were neighbors in a common patch of habitat. No song differences were associated with the presence of different coexisting species of sunbirds. Birds at distances of 10 to 400 km were little more divergent in song than birds within the 4 km2 area of the main study site. No geographic trends in song were found along more than 100 km of the coastal plain of Ghana, and no consistent differences were found between coastal and inland populations. Similarities among the songs of neighboring birds, differences between neighborhoods, and the uniform size of the song "dialects" are tentatively explained in terms of social adaptation rather than habitat adaptation.
88 citations
TL;DR: Although there are indications that Luit is going to win the competition with Nikkie over contacts with Yeroen, the ultimate choice with respect to the supporting relation will be toYeroen himself.
Abstract: [Initially the adult females supported Yeroen against his challenger, Luit. Yerocn often sat together with these supporters. Luit and the third adult male, Nikkie, together broke through these strong supporting relations of Yeroen : Luit did so mainly by isolating Yeroen from the females (through 'separating interventions') and Nikkie by keeping the females away from Yeroen-Luit conflicts. After both contesting males had achieved dominance over Yeroen, most females started to support the new α-male against the old one. During this period Yeroen seemed to become desired by Luit as a potential alliance partner. However, also Nikkie seemed to see advantages in an alliance with Yeroen. Although there are indications that Luit is going to win the competition with Nikkie over contacts with Yeroen, the ultimate choice with respect to the supporting relation will be to Yeroen himself., Initially the adult females supported Yeroen against his challenger, Luit. Yerocn often sat together with these supporters. Luit and the third adult male, Nikkie, together broke through these strong supporting relations of Yeroen : Luit did so mainly by isolating Yeroen from the females (through 'separating interventions') and Nikkie by keeping the females away from Yeroen-Luit conflicts. After both contesting males had achieved dominance over Yeroen, most females started to support the new α-male against the old one. During this period Yeroen seemed to become desired by Luit as a potential alliance partner. However, also Nikkie seemed to see advantages in an alliance with Yeroen. Although there are indications that Luit is going to win the competition with Nikkie over contacts with Yeroen, the ultimate choice with respect to the supporting relation will be to Yeroen himself.]
TL;DR: The spacing behavior, displays and aggression of hatchling and juvenile lizards (Anolis aeneus) were compared to the behavior of the adults as discussed by the authors, and the results showed that adults are more apt to give certain aggressive displays than are adults of either sex.
Abstract: The spacing behavior, displays and aggression of hatchling and juvenile lizards (Anolis aeneus) were compared to the behavior of the adults. Tn adults these behaviors are sexually dimorphic, but juveniles of both sexes show similar behavior. Hatchling lizards a few days old have nonoverlapping home ranges or participate in dominance hierarchies of up to six steps. Status in dominance hierarchies is almost entirely size dependent. The particular type of social system shown varies with microhabitat. Juvenile home ranges are smaller than those of adults and enlarge with age. Home ranges of juveniles are more variable in size than those of adults. Temporal elements of the species specific bob pattern are very stereotyped in both juveniles and adults. Intraindividual variation in display element duration is low and interindividual variation high in all age and size groups. However, mean duraton of elements is longer for larger lizards. Two other displays are significantly more variable in juveniles than in adults. Most of this variation is due to added interindividual variance in juvenile display elements. Juveniles and adults of both sexes are able to give all displays except courtship displays. The frequency with which certain displays are given is significantly different for juveniles, adult females and adult males. Juveniles are more apt to give certain aggressive displays than are adults of either sex. Longterm ontogenetic studies of individual females indicates that initially they give the aggressive displays characteristic of juveniles in general, but that the frequency of these displays decrease when they become sexually mature. When territorial resident lizards of any age are exposed to tethered intruders they react aggressively. Aggressive responses were ranked and aggression computed for certain size ratios of intruder and resident juveniles (I/R ratio). This aggression was compared to that predicted on the basis of food competition between different lizard size ratios. At both large and small lizard size ratios (I/R) juvenile Anolis aeneus are more aggressive than are either adult males or adult females at the same size ratios. This added aggressiveness to very large and very small intruders cannot be explained in terms of food competition between juvenile lizards of different sizes.
TL;DR: The results confirmed predictions that the squirrels should behave more cautiously toward rattlesnakes than toward gopher snakes, and that olfaction is an important mediator of snake-directed behavior.
Abstract: This experiment had two objectives. One was to seek evidence for greater caution by California ground squirrels (Spermophilus beccheyi) when interacting with venonnous rattlesnakes (Crotalus viridis), their most important snake predator, than when interacting with nonvenomous gopher snakes (Pituophis melanoleucus), their second-most important snake predator. The second was to examine the role of olfaction in mediating snake-directed behavior by these squirrels, since matry squirrel-snake encounters occur in burrows where visual cues are unavailable. In an illuminated room, we videotaped the responses by eight freely moving ground squirrels to the two snake species; the snakes were presented in large, transparent plastic bags that were either sealed (odor unavailable) or perforated (odor available). The results confirmed our predictions that the squirrels should behave more cautiously toward rattlesnakes than toward gopher snakes, and that olfaction is an important mediator of snake-directed behavior. Although the squirrels approached the two snake species equally often, they attended more to the rattlesnake than to the gopher snake, but remained farther away from the rattlesnake. When snake odor was available, the squirrels spent more time attending to the snakes, approached the snakes more frequently, approached the snakes in elongate postures more often and sand kicked more at the snakes. We proposed the following. 1. The antipredator strategy of snake harassment by California ground squirrels is sensitive to risk, exhibiting attenuation where risk is higher. 2. Olfaction is likely to be even more important during squirrel-snake encounters in the dark, especially in burrows. 3. The ability to recognize snakes on the basis of odor may not depend on prior experience with snakes, and may circumvent difficulties associated with visual detection of snakes.
TL;DR: In this article, the authors examined the gaze behavior of 28 mouse lemurs in their peak activity period to determine the response-eliciting effectiveness of five models varying in the number of concentric circles.
Abstract: Captive lesser mouse lemurs (Microcebus murinus) were observed to avert their heads during face-to-face encounters. Based on evidence obtained from other vertebrate species, predominantly among the Primates, it was assumed that the facing orientation and direction of gaze of an adversary was the provocative agent eliciting gaze aversion by mouse lemurs. A more precise examination of the perceptual determinants of gaze aversion employed models presenting various combinations of eyelike concentric circles. Presented side-by-side in paired comparisons, it was predicted that a model presenting two horizontally placed concentric circles, which schematically resemble two facing eyes, would elicit less visual inspection, i.e., more visual avoidance, than models presenting less physiognomic arrangements of concentric circles. Using a special model-viewing apparatus, Experiment I examined the gaze behavior of 28 mouse lemurs in their peak activity period to determine the response-eliciting effectiveness of 5 models varying in the number of concentric circles. Experiment 2 examined 50 lemurs, some of which were in seasonally and artificially induced torpor. Three models differing in the spatial orientation of two concentric circles were investigated in an attempt to control for contour complexity. Both the bout frequency and duration of model fixation were measured using head orientation as the response criterion. The following results were obtained: 1. For the over-all paired comparisons in both experiments, the model presenting two horizontally positioned concentric circles was the only model which elicited significantly fewer bouts of longer fixation. 2. Because of a lack of homogeneity in model fixation, due to intense fear in some lemurs, the lemurs were separated into homogeneous subgroups using statistical criteria in the first experiment and behavioral criteria in the second. Only the largest subgroups comprising relatively calm mouse lemurs exhibited differential model fixation at a significant level. In both experiments, these particular subgroups looked significantly less at the critical model exhibiting two schematic facing eyes than at any of the other models. In conjunction with observations of dyadic interactions among mouse lemurs, the experimental findings suggest the following: 1. Two schematic facing eyes viewed out of context with a predator or conspecific are a provocative source of stimulation eliciting less visual inspection which could be considered analogous to bouts of gaze aversion observed among interacting lemurs. 2. In concordance with laboratory observations of attenuated gaze aversion by frightened mouse lemurs, the more fear-motivated lemurs in the present experiments exhibited reduced differential model inspection. The affinity between these findings implies, perhaps, that fear-motivation increases the tendency to engage in less selective investigative gazing as the animal shifts into a protective behavior mode. This as well as any other functional interpretation of the role of gaze behavior during agonistic encounters, however, awaits further experimental support.
TL;DR: The social system of the grey squirrel was investigated and it was found that young squirrels born in a given locality have a greater chance of establishing than do immigrants.
Abstract: The social system of the grey squirrel (Sciurus carolinensis) was investigated. The area used by males and females expands after weaning, then stabilizes and remains the same in location and extent for life. The home range of an established individual is broadly overlapped by the home ranges of several other animals. Each established individual is regularly in contact with only a limited number of recognized neighbours with which it has well-established dominance relationships. Individual recognition promotes lowered aggressive levels between neighbours which allows each squirrel to use its entire home range evenly. Aggressive behaviour is directed toward strange squirrels, either young or immigrants, which attempt to enter this system. Thus, the established individuals hinder the settlement of new animals. Young squirrels born in a given locality have a greater chance of establishing than do immigrants. The relevance of the findings to population regulation is discussed.
TL;DR: The narrow degree of variability in songs of canaries with different repertoires and the finding that hybrids sing song structures which they are incapable of hearing are hints that the song patterns are genetically programmed and can only be modified by learning within a species specific range.
Abstract: The species specific song programs, by which the variation of song patterns is limited to predictable features, was analysed in the canaries, greenfinches, and hybrids between the two species. i) Canaries and greenfinches, which could not hear each other, sang different song elements. If we compare single characteristics (such as duration, highest frequency) rather than overall characteristics the elements of different individuals for the same species are very similar. 2) The tour, a rhythmical repetition of identical vocal patterns, is the most typical feature of all songs analysed. These tours have, in all birds, a similar rhytlunical timing. There is a strong correlation between the duration of elements and the interval which follows. 3) Species specific song differences are found in the higher song structure. There is no phrase in the greenfinch. 4) There is no phrase in the songs of hybrids, a feature shared with greenfinches but not canaries. The lengths of tours and the timbre of elements are intermediate with a narrow degree of intra-individual variability. The size of the repertoire is within the range of the parental species. 5) The narrow degree of variability in songs of canaries with different repertoires and the finding that hybrids sing song structures which they are incapable of hearing are hints that the song patterns are genetically programmed and can only be modified by learning within a species specific range.
TL;DR: The properties of a simple model for the interactions between a number of behaviour patterns competing for a single output pathway demonstrate the marked influence which competition can have on the output of individual systems, so making it hard to discover any pattern intrinsic to those systems.
Abstract: This paper explores the properties of a simple model for the interactions between a number of behaviour patterns competing for a single output pathway. In the model, the level of causal factors for each of five competing acts oscillates between start and stop thresholds, rising during non-performance and falling during performance. A sixth, residual, category is shown when none of the other behaviour patterns has been initiated by its level reaching the start threshold. The characteristics of each of the competing acts were chosen, as far as possible, to be similar to those of behaviour patterns previously studied in zebra finches. Were it not for competition, each of the competing acts would have shown cycles in its occurrence with bouts of fixed length taking place at fixed intervals. Competition led several of them to show no cycle in occurrence and to have bout lengths which followed a random, negative exponential, distribution. Only acts with low intrinsic bout lengths exhibited their natural patterns under conditions of competition, the extent to which they did so depending on the degree of competition. As competition became stronger, bout and gap lengths became shorter and, with intense competition, the output was non-stationary. The influence of competition was, however, more than a disruptive one: under some circumstances behaviour patterns showed clear cycles of a different length from those with which they had been endowed, and the matrix of first-order transitions between acts also diverged from randomness. The output of the simulations is discussed in relation to the behaviour of zebra finches and several points of similarity are noted. For example, feeding and ruffling in the finches, like the two simulated acts based on their characteristics, are the behaviours most likely to show a regular pattern of occurrence. Failure to find this in the other patterns of zebra finch behaviour may be because competition hides their intrinsic pattern rather than because they are not scheduled to occur regularly. While the model used is a very simple one, and there are many ways in which it is unrealistic, it demonstrates the marked influence which competition can have on the output of individual systems, so making it hard to discover any pattern intrinsic to those systems. Simple as it is, the model leads to a complex output and a number of testable predictions : it highlights the point that complexity is bound to arise when several acts compete for expression regardless of how simple are the mechanisms underlying each individual behaviour pattern.
TL;DR: The unique sociality of Nauphoeta has marked influence on all aspects of agonistic behaviour of this species and types of interactions change as dominance hierarchies become stabilized.
Abstract: I. Agonistic interactions of Nauphoeta cinerea males were investigated with regard to establishment of dominance hierarchies and informational analysis of agonistic acts. 2. Dominance/subordinance sociality influences the behavioural acts of individuals in addition to the inherent information of an agonistic act. 3. Types of interactions change as dominance hierarchies become stabilized. 4. The unique sociality of Nauphoeta has marked influence on all aspects of agonistic behaviour of this species.
TL;DR: Maternal aggressive behavior of northern elephant seals enhances reproductive success by increasing the likelihood of pup survival and correlated negatively with the number of times the pup was bitten by alien females.
Abstract: Maternal aggressive behavior of northern elephant seals enhances reproductive success by increasing the likelihood of pup survival. Detailed observations of marked mother-pup pairs revealed that female aggressiveness increased dramatically after giving birth. Maternal aggressiveness also correlated negatively with the number of times the pup was bitten by alien females. Mothers of these pups were less aggressive than the 17 whose pups survived. Pup behavior was not directly related to mortality. Frequencies of interfemale aggressive encounters were compared for different beach areas. Aggression was most frequent on the smallest area, where interfemale distance was the shortest, and tidal action extreme. Aggression was least frequent on the sparcely populated beach, affected little by tide or male activity. Interfemale distance was greatest here. Reproductive advantages and disadvantages of pupping on each area are noted.
TL;DR: In this paper, the authors investigated the behavior of Northwestern crows (Corvus caurinus) feeding on whelks (Thais lamellosa) in the intertidal zone and found that crows typically flew almost vertically up, released the whelk and then dove after it.
Abstract: Prey selection, dropping behaviour and dropping site selection was investigated in Northwestern crows (Corvus caurinus) feeding on whelks (Thais lamellosa). Crows selected only the largest whelks available in the intertidal zone. Although equally palatable, smaller whelks were ignored. Crows assessed size of whelks first by sight and then by weight. Thus, some were picked up with the bill and laid down again before a final selection was made. Rejects were longer and heavier than available whelks and shorter and lighter than selected ones. Usually, crows carried and dropped only one whelk at a time. While dropping, crows typically flew almost vertically up, released the whelk and then dove after it. The mean number of drops required to break a whelk was 4.36. Crows dropped whelks until they could obtain most or all of the soft parts. Usually crows did not give up dropping a whelk until it broke. The mean height of drop was 5.23 m. Crows had a tendency to increase height of drop over successive attempts. During most flights, crows lost some height before releasing a whelk. Presumably, this allowed them to watch whelks fall and bounce. All whelks were dropped onto rock. None were released over water or grass. Crows had specific dropping sites. This was because they selected hard substrate and safe sites for dropping. On dropping sites whelks were unlikely to bounce into water. Results were compared with those of other studies of dropping behaviour in gulls and hawks. Dropping behaviour in crows seems to be much more adaptable than in gulls.
TL;DR: Les interactions sociales, la rA©partition spatiale et le comportement lors d'une situation de compA©tition alimentaire ont A©tA© AÕtudiAÔs sur deux troupeaux de gAÕnisses constituA©s chacun par la r AÔunion de 3 groupes de 4 animaux, placAÒs ensemble soit AÒ 6 mois soit 12 mois as discussed by the authors.
Abstract: Les interactions sociales, la rA©partition spatiale et le comportement lors d'une situation de compA©tition alimentaire ont A©tA© A©tudiA©s sur deux troupeaux de gA©nisses constituA©s chacun par la rA©union de 3 groupes de 4 animaux, placA©s ensemble soit A 6 mois soit A 12 mois. Les rA©sultats obtenus sur ces deux troupeaux ont A©tA© comparA©s A ceux obtenus, au cours d'une prA©cA©dente A©tude, sur un troupeau constituA© par la rA©union de 4 groupes de 4 animaux A©levA©s ensemble depuis la naissance. Quelque soit l'A¢ge auquel les animaux ont A©tA© regroupA©s, ils A©changent moins d'interactions agonistiques entre eux qu'avec des animaux rencontrA©s plus tard; mais cette diffA©rence ne se retrouve plus 6 mois aprA¨s la rA©union des groupes constituA©s A 6 ou 12 mois alors qu'elle persiste au moins un an aprA¨s la rA©union des groupes d'A©levage. De plus, les animaux rA©unis A 6 ou 12 mois sont plus agressifs entre eux que ceux A©levA©s ensemble depuis la naissance. Ils ne sont pas spatialement associA©s (sauf lors de l'alimentation) contrairement A ceux A©levA©s ensemble; enfin ils ne montrent pas de tolA©rance particuliA¨re lors d'une situation de compA©tition alimentaire. Il semble exister une pA©riode de sensibilitA© particuliA¨re pour la crA©ation des relations prA©fA©rentielles entre les individus d'un groupe ; elle se situerait avant 6 mois chez les Bovins, et pourrait Aatre limitA©e par l'apparition des relations de dominance.
TL;DR: Male ring-tailed lemurs (Lemur catta) show a stereotyped sequence of behaviour when investigating the genital scent of conspecific females, which may be to transport non-volatile substances to and from the vomeronasal organ, a specialised chemoreceptor.
Abstract: Male ring-tailed lemurs (Lemur catta) show a stereotyped sequence of behaviour when investigating the genital scent of conspecific females. The scent is first lapped with the tip of the tongue. The male then gives a rapid, sneeze-like inspiration, at the same time turning his head and hriefly retracting the upper lip. There follows a prolonged gape, during which the mouth is held half open and the tongue flattened against the lower teeth. Finally, the rhinarium is often licked. The whole cycle may then be repeated. This behaviour is considered to be an example of flehmen. Its purpose may be to transport non-volatile substances to and from the vomeronasal organ, a specialised chemoreceptor. A functional model of this process is outlined.
TL;DR: Individual differences in acoustic features and rates of vocalization are correlated with stages of social development, serve as contextual cues, and are an important source of variability in primate communication.
Abstract: Recordings were made of contact-location vocalizations and behaviors of six troop-living juvenile stumptail macaques. Quantitative analysis of 354 spectrograms distinguished thirteen of the fifteen pairs of animals and led to construction of a "profile" of distinctive acoustic features for the vocalizations of each animal. Individual variation was also found in vocalization occurrence rates in five contextual categories. Acoustic distinctions found between two behavioral contexts were the same found to differentiate similar social settings in Japanese macaques (GREEN, 1975). Individual differences in acoustic features and rates of vocalization are correlated with stages of social development, serve as contextual cues, and are an important source of variability in primate communication.
TL;DR: Field surveys and field experiments revealed that individuals preferred to maintain a territory in an inferior position within a large group than to be isolated on prime habitat, which has support since an individual's mobility outside the boundaries of its colony was limited.
Abstract: 1. The damselfish Eupomacentrus Planifrons develops dense territorial populations in staghorn coral (Acropora cervicornis). 2. Field surveys and field experiments revealed that individuals preferred to maintain a territory in an inferior position within a large group than to be isolated on prime habitat. 3. Individuals in inferior positions within the group often meandered about the colony ("forays") in search of vacancies within superior habitats. 4. The size of the damselfish was correlated with habitat quality with larger individuals being found in superior portions of the staghorn colony. As areas became vacant, they were populated by individuals of similar size to the previous owner and to surrounding individuals. 5. As both males and females maintained territories within a colony, the larger colonies gave individuals greater access to potential mates. This has support since an individual's mobility outside the boundaries of its colony was limited and the most courtship was observed in the largest colonies. 6. Similarities between permanent territorial colonies and dominance systems are discussed.
TL;DR: The efficiency of the Wren's song may be impaired by certain background noises as discussed by the authors, such as those emitted by sympatric birds, which decrease the receiving Wrens alertness.
Abstract: The efficiency of the Wren's song may be impaired by certain background noises. Natural noises, such as those emitted by sympatric birds decrease the receiving Wren's alertness (Table 1). This phenomenon has no compensating process and is probably rather detrimental to communication between Wrens in an acoustically rich natural environment. When the Wren's song is masked with artificially made signals there are no serious ethological consequences (Table 2) as masking is seldom complete, and decrease in the received information is largely compensated by the song's inherent redundancy. The precise requirements for a mask to hinder communication efficiency are described. They are so stringent that the odds are overwhelmingly against their being ever met with in nature.
TL;DR: The results suggest that the squirrels' snake-directed behavior is sensitive to risk and that squirrels extract information from the snake's rattling sounds about the potential costs and benefits of interacting with a rattlesnake.
Abstract: California ground squirrels (Spermophilus beecheyi) approach, harass and even attack one of their important predators, the rattlesnake (Crotalus viridis). In some of these encounters, rattlesnakes respond with defensive behavior, including rattling. Although the rattle functions primarily as an aposematic signal, we hypothesized that the squirrels extract from the sound the following additional information which indicates the risk associated with interacting with the snake. 1. Rattling indicates that the snake is in a defensive motivational state, which appears to be associated with both a low probability of envenomation and a high probability of retreat by the snake. 2. The intensity and spectral composition of the rattling sound indicates the size of the snake, and risk to the squirrel is positively correlated with snake size. The purpose of these two experiments was to test these hypotheses by exaemining the influence of the rattling sound on the snake-directed behavior of California ground squirrels. In the first experiment we video taped the responses of squirrels to a rattlesnake when it could rattle normally, and to the same snake when its rattle was silenced. In the second experiment, we compared the reactions of squirrels to recordings of the rattling sounds of a large and a small rattlesnake. We found the following. 1. The rattling sound potentiated both contact-promoting and contact-reducing snake-directed behavior by the squirrels. Although the onset of a rattle episode startled the squirrel, the rattle's overall effect was to intensify harassment by the squirrel. Squirrels sand kicked more and at a higher rate and harassed the snake longer when the snake could rattle than when the rattles were silenced. 2. The nature of the rattle's potentiating effect on snake-directed behavior by the squirrel depended on the size related information in the rattling sound. Squirrels turned and ran away from a recording of a large rattlesnake, but approached and investigated a recording of a small rattlesnake. These results suggest both that the squirrels' snake-directed behavior is sensitive to risk and that squirrels extract information from the snake's rattling sounds about the potential costs and benefits of interacting with a rattlesnake.
TL;DR: In this paper, a two-year field study of wild mountain gorillas showed that patterns of social interaction do indeed change with the predominant maintenance activity: neglect of such variation can lead to ignorance of interesting facets of behaviour and, at worst, misleading conclusions about the social relationships of the study animals.
Abstract: Animals tend to divide their days into longish periods of different predominant maintenance activities, such that, for instance, early morning and late afternoon feeding periods are clearly separated by a midday rest period. Frequencies of social behaviour are known to change with change in the predominant activity. As an obvious example, grooming tends to be more frequent during rest periods than when the animals are moving and feeding. However, the possibility that patterns, as opposed to frequencies, of social interaction could change through the day has rarely been mentioned, let alone considered in detail. Data from a two-year field study of wild mountain gorilla, show that patterns of social interaction do indeed change with the predominant maintenance activity : neglect of such variation can lead to, at best, ignorance of interesting facets of behaviour and, at worst, misleading conclusions about the social relationships of the study animals.
TL;DR: The hypothesis that nest raiding is adaptive because it increases the relative attractiveness of the raider to females is compatible with the hypothesis that raiding should occur more often when the female was present.
Abstract: The purpose of this experiment was to test the hypothesis that the disruptive acts (nest raiding), directed by male three-spined sticklebacks, Gasterosteus aculeatus L., toward the eggs and nests of conspecific males evolved as a result of intrasexual selection. We compared the frequency with which a resident male was raided by neighbors when a transparent cylinder containing a male was introduced into his territory, with the frequency of raiding during the presence of a similarly introduced female. On the basis of the intrasexual selection hypothesis, we predicted that raiding should occur more often when the female was present. We also studied the relationship between raiding and the relative dominance status of raided and raiding males. If raiding and dominance conflict are alternative strategies in intrasexual competition, then raiding should have been most intense when raided and raiding males were least discrepant in dominance status. Resident males responded appropriately to introduced fish, i.e., with more courtship and nesting behavior toward females and more aggression toward males. Introduced females were much more effective in eliciting raiding by neighbors than introduced males. The highest status neighbors tended to raid the most. There was some evidence that raiding reduced the raided male's courtship motivation. The outcome of the study is compatible with the hypothesis that nest raiding is adaptive because it increases the relative attractiveness of the raider to females.
TL;DR: The evidence favors an interpretation based on the greater opportunity for social conditioning in the field environment and the blocking of habitual behavior patterns (i.e. escape) in captivity.
Abstract: The agonistic behavior of field-trapped and first-generation laboratory-reared wild male Norway rats was compared in a resident-intruder context in order to examine the hypothesis that aggressive behavior is significantly reduced by laboratory rearing. In addition isolate and group-reared wild and domestic rats were compared in order to determine the effect of early social deprivation on levels of aggression. Experimental subjects were housed in test chambers for at least one month prior to their exposure to anosmic hybrid (wild X domestic) intruders. Agonistic behaviors of both residents and intruders were recorded in two 30-minute trials. Field-trapped males were significantly more aggressive than any of the laboratory-reared groups. The behavior of isolate-reared subjects of both stocks did not differ significantly from their group-reared counterparts. Three hypotheses were advanced to account for the greater aggressiveness of the wild-caught rats. The evidence favors an interpretation based on the greater opportunity for social conditioning in the field environment and the blocking of habitual behavior patterns (i.e. escape) in captivity.
TL;DR: Male pumpkinseed sunfish (Lepomis gibbosus) readily attacked plywood models placed into their nests, indicating that in the pattern of the male pumpkinseed, the red portion of the opercular flap and the red iris are social releasers for aggressive behavior.
Abstract: Male pumpkinseed sunfish (Lepomis gibbosus) readily attacked plywood models placed into their nests. Models containing red features (iris, opercular flap) received more attacks and aggressive displays than models lacking these features or than models which had these features painted black. This indicates that in the pattern of the male pumpkinseed, the red portion of the opercular flap and the red iris are social releasers for aggressive behavior. These features fade in subordinate pumpkinseeds in the laboratory and also in female pumpkinseeds before they enter the male's nest during reproduction. This pattern change would therefore function to decrease aggressive behavior directed at these individuals. A conspicuous feature of the female pumpkinseed is the presence of lateral bars. When bars were added to models, reductions in aggressive behavior were consistently observed. Hence, bars appear to inhibit male aggression. Bluegill sunfish (L. macrochirus) nest sympatrically with pumpkinseeds and interspecific nest defense was commonly seen. A conspicuous feature of male bluegills is a dark spot in the area of the dorsal fin rays. When such a spot is added to models, increases in aggressive behavior were observed in male pumpkinseeds. Hence, this feature may provide a basis for interspecific recognition and reproductive isolation. Finally, pumpkinseeds responded more vigorously to models than did bluegills. This may imply that the former are more attuned to morphological features than the latter. Bluegills, on the other hand, may be more attuned to the behavior of nest intruders. This hypothesis agrees with differences in the nesting ecology of these species.