Showing papers in "Canadian Journal of Zoology in 1986"
TL;DR: The basic inefficiency of the jet-propulsion system has required bioenergetic, physiological, and biochemical adaptations in squid which maximize their metabolic rates, which resulted in the short life history and semelparous reproductive patterns that seem to characterize these coleoid cephalopods.
Abstract: The convergent evolution of cephalopods and fish has often been discussed on an anatomical basis, but recent advances in the knowledge of cephalopod life cycles, physiology, and biochemistry suggest that there are constraints on cephalopods that prevent them from competing directly with fish. These advances are reviewed against the background of detailed information on fish from the perspective that the basic inefficiency of the jet-propulsion system has required bioenergetic, physiological, and biochemical adaptations in squid which maximize their metabolic rates. Such "high-energy" adaptations are suggested to have resulted in the short life history and semelparous reproductive patterns that seem to characterize these coleoid cephalopods. Conversely, the physiology and biochemistry offish give them distinct advantages for long lives and iteroparity.
276 citations
TL;DR: An experiment was conducted on one of these areas (with the others as controls) to test the effect of wolf numbers on herd growth, and reduced wolves at the experimental Horseranch population from 10 to 1–4/1000 km2 and these caibou increased.
Abstract: Major fluctuations in caribou (Rangifer tarandus) numbers have occurred since the settlement of European man in British Columbia. Caribou declined in the late 1930's and 1940's after moose (Alces a...
223 citations
TL;DR: This paper examines patterns in the linear distribution of helminths in the small intestine of each of 45 scaup.
Abstract: This paper examines patterns in the linear distribution of helminths in the small intestine of each of 45 scaup. Over all birds, most common species of helminths were found in over half of the small intestine; their distributions overlapped broadly. In individual birds, each species occupied a more restricted, predictable part of the intestine; "core species" (those present in more than two-thirds of the birds) were more evenly distributed along the intestine than expected by chance and occupied almost all of it; "secondary species" (those in one- to two-thirds of the birds) were clumped in anterior and posterior portions of the intestine; and "satellite species" (those in less than one-third of the birds) were randomly distributed. For all common helminths, the range occupied in individual birds was significantly correlated with population size; however, overlap between adjacent species did not increase with increases in their total numbers. The intestinal helminths of scaup belonged to three guilds: sma...
221 citations
TL;DR: The helminth communities of the small intestines of 45 lesser scaup ducks sampled from 13 lakes in Alberta, Canada, were examined for patterns of association among species and a core of eight frequent, numerous, and positively associated species provided a basic similarity across all host individuals.
Abstract: The helminth communities of the small intestines of 45 lesser scaup ducks sampled from 13 lakes in Alberta, Canada, were examined for patterns of association among species. A core of eight frequent...
213 citations
TL;DR: A critical review of metabolic rate determinations for pinnipeds and cetaceans does not support the widely accepted generalization that they have higher metabolic rates than terrestrial mammals of similar size, forcing a rethinking of the thermoregulatory adaptations of these marine mammals for an aquatic existence.
Abstract: A critical review of metabolic rate determinations for pinnipeds (seals, sea lions, fur seals, and walrus) and cetaceans (whales, dolphins, and porpoises) does not support the widely accepted gener...
209 citations
TL;DR: Resistance to heat load was greater for standing moose during summer; respiration rate increased above 14 °C and open-mouthed panting began at 20 °C, and moose were easily heat stressed.
Abstract: Metabolic rates and thermoregulatory responses were studied in adult moose (Alces alces) exposed to various ambient temperatures during winter and summer. Resting energy expenditures followed a mar...
199 citations
TL;DR: Heterogeneity of slopes or allometric coefficients resulted in different estimates of shape for the same individual for pooled common-within and within-groups data, such that considerably different biological interpretations of group interrelationships resulted.
Abstract: Univariate computation of residuals or allometric variates should be used to estimate the shape of body parts of ectothermic vertebrates. For studies involving more than one group, three types of relationships may be used to calculate the slopes or allometric coefficients necessary for computing the shape variate: pooled group, common-within groups, and individual-within groups. For both residuals and allometric variates, the pooled and common-within groups coefficients resulted in similar estimates of shape when there was no between-group heterogeneity in relationships. Within-group coefficients resulted in quite different estimates of shape. Heterogeneity of slopes or allometric coefficients resulted in different estimates of shape for the same individual for pooled common-within and within-groups data. Such differences in the shape variates were cumulative in subsequent analyses such that considerably different biological interpretations of group interrelationships resulted. Thus, if any between-group ...
192 citations
TL;DR: Changes in the benthic community were the result of catastrophic drift, and distinct immediate and delayed responses of diurnal drift to the saltating sediments were evident.
Abstract: Field experiments were conducted to investigate the responses of benthic macroinvertebrate communities to experimental additions of fine sediments into riffles having a flow with either low tractive force so the sediments were deposited or sufficient tractive force to transport the added sediments. Sediment deposition had no measurable impact on most taxa, the only negative effects being significantly higher drift rates and lower benthic densities for Paraleptophlebia. Sediment transport by saltation created a physical disturbance that reduced total benthic densities by >50% in 24 h and significantly influenced macroinvertebrate community composition. Changes in the benthic community were the result of catastrophic drift, and distinct immediate and delayed responses of diurnal drift to the saltating sediments were evident. Taxa with the immediate drift response resided predominantly at the substrate surface and were instantaneously exposed to scouring as sediments were added. Macroinvertebrates showing th...
189 citations
TL;DR: Prolonged and burst, or "fast-start," swimming were measured in anadromous and resident freshwater sticklebacks, and differences in habitat and life histories in the two forms of Ga...
Abstract: Prolonged and burst, or "fast-start," swimming were measured in anadromous and resident freshwater sticklebacks. In prolonged swimming tests conducted at 5 body lengths/s, anadromous sticklebacks fatigued less easily than freshwater sticklebacks. Anadromous sticklebacks also had larger pectoral fins and less robust bodies than freshwater sticklebacks. At the start of a burst swimming sequence (kinematic stage 1), freshwater sticklebacks curved their bodies more than anadromous sticklebacks, but trailing-edge amplitudes were the same in both forms. During kinematic stage 2, freshwater sticklebacks had greater trailing-edge amplitudes than anadromous fish, but body curvature was the same in both forms. During burst swimming, freshwater sticklebacks attained both higher maximum and mean velocities than anadromous sticklebacks and also travelled a greater distance in the first 50 ms (2.67 vs. 1.98 cm). These results are discussed with respect to differences in habitat and life histories in the two forms of Ga...
184 citations
TL;DR: It is proposed that the dynamics of sea ice and the associated variability in access to food have played a major role in the evolution of the social structure and mating system of polar bears.
Abstract: Polar bears are intimately associated with arctic sea ice and their distribution is approximated by its winter extent. They are the only terrestrial mammals, other than humans, to have adapted so c...
173 citations
TL;DR: The muscle fibers of superficial (ventral) and deep (dorsal) samples from the pectoralis muscle of 43 species of carinate birds are characterized histochemically on the basis of their myofibrillar adenosine triphosphatase (mATPase) activity after acidic and alkaline preincubations.
Abstract: The muscle fibers of superficial (ventral) and deep (dorsal) samples from the pectoralis muscle of 43 species of carinate birds are characterized histochemically on the basis of their myofibrillar ...
TL;DR: Humpback whale (Megaptera novaeangliae) social vocalizations (nonsong sounds) were clearly related to whale group size and surface activity and social sounds occurred almost exclusively in groups.
Abstract: Humpback whale (Megaptera novaeangliae) social vocalizations (nonsong sounds) were clearly related to whale group size and surface activity. Social sounds occurred almost exclusively in groups cont...
TL;DR: It is suggested that bats roost to take advantage of site-specific factors that may increase reproductive success, and after eviction they move short distances to new roosts where they tended to produce fewer offspring.
Abstract: We used radio tracking and direct observation to determine the effect of roost closure on the roosting and foraging behaviour of big brown bats (Eptesicus fuscus) in maternity colonies near Ottawa. Individuals were site loyal, but after eviction they moved short distances to new roosts where they tended to produce fewer offspring. The time spent on the first foraging flight, the maximum distance travelled, and the use of feeding areas did not change with exclusion. The results suggest that bats roost to take advantage of site-specific factors that may increase reproductive success.
TL;DR: It is suggested that the high costs of tail loss in Eumeces are offset by the increased probability of predator escape via tail loss, as well as the temporary loss of the autotomy adaptation.
Abstract: The tail loss adaptation in Eumeces of the southeastern United States is complex. Juveniles possess tails that are colored differently from those of adults and apparently distract the attention of ...
TL;DR: This work experimentally investigated the feeding motivation of lower modal group salmon from July to September of their 1st year, and found a general shift in foraging strategy in most fish towards minimizing the costs of obtaining food.
Abstract: It is known that juvenile Atlantic salmon populations divide into two size categories in their first autumn. The larger fish migrate to sea the next summer, whereas the lower modal group fish remain in freshwaters for at least another year. The size difference arises from a reduced food intake by lower modal group fish in autumn. We experimentally investigated the feeding motivation of lower modal group salmon from July to September of their 1st year. Feeding motivation declined through the season, regardless of competition, food supply, or water temperature. This was evident at each stage in the sequence of capturing prey: orientation was less likely to lead to attack, and an attack was less likely to result in the food being consumed. Fish also reduced the distances over which they would travel to intercept food, and delayed their attacks until passing particles had reached their closest approach. There was thus a general shift in foraging strategy in most fish towards minimizing the costs of obtaining ...
TL;DR: It is likely that bicarbonate entry into the erythrocyte in exchange for intracellular chloride, rather than branchial CO2 diffusion or blood/water convection, is the rate-limiting process in carbon dioxide excretion, although a change in any one of these factors will affect overall CO2 elimination.
Abstract: The pattern and control of carbon dioxide excretion in fish is reviewed with particular emphasis on the site(s) of bicarbonate dehydration, the involvement of diffusive and convective processes, an...
TL;DR: The rate of breakdown of plant particles in the rumen of mule deer and elk was investigated to determine if plant chemical or structural composition affects the animals' behaviour.
Abstract: The rate of breakdown of plant particles in the rumen of mule deer (Odocoileus hemionus) and elk (Cervus elaphus) was investigated to determine if plant chemical or structural composition affects p...
TL;DR: A simple, inexpensive method for tracking small mammals accurately for distances up to 180 m by spooling a small spool of thread attached to the back of the animal with srgical glue.
Abstract: We describe a simple, inexpensive method for tracking small mammals accurately for distances up to 180 m. A small spool of thread is attached to the back of the animal with srgical glue. As the animal moves along, it leaves behind it a trail of thread that can be followed along the route taken and to nest sites. Of 157 lactating meadow voles spooled, we found 62 nests with young. This success rate can probably be doubled by reducing two sources of spooling failure and by spooling a second time within the same trapping session.
TL;DR: Young pond snails of three species were allowed free access to waterfowl feathers floating on the surface of shallow containers, and snails adhering to the feathers were subjected to simulated flight conditions by placing them in an air stream.
Abstract: Young pond snails of three species (Lymnaea stagnalis, Stagnicola elodes, and Helisoma trivolvis) were allowed free access to waterfowl feathers floating on the surface of shallow containers. Snail...
TL;DR: Estimated mean energy expenditure by females from conception to the time of weaning (maternal investment), including the heat increment of gestation, cost of foetal tissue, and energy contained in milk acquired during the nursing period, was greater for male than for female offspring.
Abstract: Male grey seals are larger at birth, grow faster during the nursing period, and are weaned at a heavier mass than females. Estimated mean energy expenditure by females from conception to the time of weaning (maternal investment), including the heat increment of gestation, cost of foetal tissue, and energy contained in milk acquired during the nursing period, was greater for male than for female offspring. This pattern of energy investment by female grey seals in their young is consistent with Maynard Smith's model of sexual investment (J. Maynard Smith. Behav. Ecol. Sociobiol. 7: 247–251. 1980).
TL;DR: Tissue-specific metabolism in the freeze tolerant frog, Rana sylvatica, was monitored over a course of 3 days of freezing exposure at −2.5 °C followed by 11 days of thawing at 3 °C to indicate this organ as the major site of cryoprotectant production during freezing.
Abstract: Tissue-specific metabolism in the freeze tolerant frog, Rana sylvatica, was monitored over a course of 3 days of freezing exposure at −2.5 °C followed by 11 days of thawing at 3 °C. Freezing induce...
TL;DR: The overall duration of the period of shedding and regeneration, from first descent of the hair bulbs on the face and flippers to full emergence of new hair on the back, was estimated as 120–170 days.
Abstract: Cellular, hormonal, and metabolic changes during annual molts and regeneration of the pelage were studied in two harbor and five spotted seals of different ages. Seals were maintained in an appropriate photoperiod and monitored biweekly to monthly by measuring their serum cortisol, thyroxine, and triiodothyronine and their standardized resting metabolic rate. Concurrently, external signs of their molt (shedding of hair) were recorded, and samples of skin were collected from the midback for histological determination of the duration of the regenerative phase of the pelage cycle. Timing of the molts coincided with those of free-ranging seals in the natural environment. The overall duration of the period of shedding and regeneration, from first descent of the hair bulbs on the face and flippers to full emergence of new hair on the back, was estimated as 120–170 days. During the period of descent of the hair bulbs and initial growth of new hair on the back, the resting metabolic rate declined an average of 18...
TL;DR: In this article, the influence of insects (mosquitoes and oestrids) on the distribution, microhabitat choice, and behavior of a population of mountain caribou was examined.
Abstract: This study examined the influence of insects (mosquitoes and oestrids) on the distribution, microhabitat choice, and behavior of a population of mountain caribou. The study was conducted in the Bur...
TL;DR: Fecal samples were collected from the northern flying squirrel to demonstrate the functional diversity an individual species lends to its habitat when viewed in a functional context.
Abstract: Fecal samples were collected over 27 months from the northern flying squirrel (Glaucomys sabrinus (Shaw)), a mycophagist in the Pacific Northwest portion of its range. Nine genera of hypogeous Basi...
TL;DR: The underwater vocalizations of white whales, Delphinapterus leucas, summering at Cunningham Inlet, Northwest Territories, were recorded from mid-July to mid-August 1981 to 1983.
Abstract: The underwater vocalizations of white whales, Delphinapterus leucas, summering at Cunningham Inlet, Northwest Territories, were recorded from mid-July to mid-August 1981 to 1983 A total of 807 ton
TL;DR: This work has analysed both intra- and inter-specific variation in mitochondrial DNA sequences of the five North American species of the genus Oncorhynchus and the rainbow trout species, Salmo gairdneri, suggesting the existence of population substructuring.
Abstract: The salmonids of Pacific North America are a group of closely related species with complex life histories and interesting distribution. Previous studies of their evolution and population structure ...
TL;DR: Differences in call design may explain dietary differences between the two species of hoary and silver-haired bats in Manitoba, Canada.
Abstract: Amongst aerial-feeding insectivorous bats, differences in the design of echolocation calls appear to be associated with differences in foraging strategy. Recordings and observations of hoary (Lasiu...
TL;DR: Experiments designed to examine the use of otoliths recovered in stomach contents to interpret food consumption of wild seals fed Atlantic herring found a significant relationship between the state of digestion of a seal's stomach contents and the duration of time since it had fed.
Abstract: Thirteen captive phocid seals (10 grey seals (Halichoerus grypus), 2 harp seals (Phoca groenlandica), and 1 ringed seal (P. hispida)) were fed Atlantic herring (Clupea harengus harengus) in experiments designed to examine the use of otoliths recovered in stomach contents to interpret food consumption of wild seals. The percentage of ingested otoliths recovered in the stomach contents decreased with the time elapsed after feeding; 100% of otoliths were recovered between 0 and 3 h after feeding and 0% were recovered by 12.9 h after feeding. Absence of otoliths in the large intestine of seals having fed 3 to 6 h previous indicated that unrecovered otoliths had been digested (i.e., a complete disappearance of whole otoliths) while in the stomach. A significant relationship was also evident between the state of digestion of a seal's stomach contents, as measured by the proportion of otoliths remaining in skull cases (skull-recovered otoliths), and the duration of time since it had fed. These relationships have...
TL;DR: Previous studies have established that the capacity of the glycopeptide antifreezes to depress the freezing temperature of aqueous solutions is positively correlated with molecular weight, and whether a similar correlation existed within the ant ifreeze peptides was investigated.
Abstract: Previous studies have established that the capacity of the glycopeptide antifreezes to depress the freezing temperature of aqueous solutions is positively correlated with molecular weight. The pres...
TL;DR: The volume of milt that could be stripped from male goldfish, Carassius auratus, increased dramatically when fish were exposed overnight to water with concentrations of 17,20β-dihydroxy-4-pregnen-3-one (17,20P) as low as 10−10 M.
Abstract: The volume of milt that could be stripped from male goldfish, Carassius auratus, increased dramatically when fish were exposed overnight to water with concentrations of 17α,20β-dihydroxy-4-pregnen-3-one (17,20P) as low as 10−10 M. A variety of free steroids (pregnenolone, androstenedione, testosterone, 11-ketotestosterone, 17β-estradiol) and glucuronated steroids (etiocholanolone glucuronide, testosterone glucuronide, 17β-estradiol glucuronide), suggested by others to function as pheromones in fish, failed to increase milt volume at a concentration of 5 × 10−9 M. The milt response appears to be specific to 17,20P and progesterone precursors (17α-hydroxyprogesterone, progesterone), but is most sensitive to 17.20P. Because bilateral section of the olfactory tracts completely blocked the milt response to 17.20P, it is believed to be a pheromone. Selective sectioning of the lateral and medial subdivisions of the olfactory tracts demonstrated that the milt response to 17,20P is dependent on the medial tract. I...