ION, GENERAL CONCEPTIONS, SELF-CONSCIOUSNESS, MENTAL INDIVIDUALITY. It would be very difficult for any one with even much more knowledge than I possess, to determine how far animals exhibit any traces of these high mental powers. This difficulty arises from the impossibility of judging what passes through the mind of an animal; and again, the fact that writers differ to a great extent in the meaning which they attribute to the above terms, causes a further difficulty. If one may judge from various articles which have been published lately, the greatest stress seems to be laid on the supposed entire absence in animals of the power of abstraction, or of forming general concepts. But when a dog sees another dog at a distance, it is often clear that he perceives that it is a dog in the abstract; for when he gets nearer his whole manner suddenly changes, if the other dog be a friend. A recent writer remarks, that in all such cases it is a pure assumption to assert that the mental act is not essentially of the same nature in the animal as in man. If either refers what he perceives with his senses to a mental concept, then so do both. (44. Mr. Hookham, in a letter to Prof. Max Muller, in the 'Birmingham News,' May, 1873.) When I say to my terrier, in an eager voice (and I have made the trial many times), "Hi, hi, where is it?" she at once takes it as a sign that something is to be hunted, and generally first looks quickly all around, and then rushes into the nearest thicket, to scent for any game, but finding nothing, she looks up into any neighbouring tree for a squirrel. Now do not these actions clearly shew that she had in her mind a general idea or concept that some animal is to be discovered and hunted? It may be freely admitted that no animal is self-conscious, if by this term it is implied, that he reflects on such points, as whence he comes or whither he will go, or what is life and death, and so forth. But how can we feel sure that an old dog with an excellent memory and some power of imagination, as shewn by his dreams, never reflects on his past pleasures or pains in the chase? And this would be a form of self-consciousness. On the other hand, as Buchner (45. 'Conferences sur la Theorie Darwinienne,' French translat. 1869, p. 132.) has remarked, how little can the hardworked wife of a degraded Australian savage, who uses very few abstract words, and cannot count above four, exert her self-consciousness, or reflect on the nature of her own existence. It is generally admitted, that the higher animals possess memory, attention, association, and even some imagination and reason. If these powers, which differ much in different animals, are capable of improvement, there seems no great improbability in more complex faculties, such as the higher forms of abstraction, and selfconsciousness, etc., having been evolved through the development and combination of the simpler ones. It has been urged against the views here maintained that it is impossible to say at what point in the ascending scale animals become capable of abstraction, etc.; but who can say at what age this occurs in our young children? We see at least that such powers

https://www.jstage.jst.go.jp/article/ase1887/22/257/22_257_458/_pdf

The descent of man and selection in relation to sex

Mammals of the Neotropics: The Southern Cone. Volume 2: Chile, Argentina, Uruguay, Paraguay.Kent H. Redford , John F. Eisenberg

Cooperative hunting is believed to have important implications for the evolution of sociality and advanced cognitive abilities. Variation in the level of hunt organisation amongst species and how their cognitive, behavioural and athletic adaptations may contribute to observed patterns of cooperative hunting behaviour, however, are poorly understood. We, therefore, reviewed the literature for evidence of different levels of hunt organisation and cooperation in carnivorans and examined their social and physical adaptations for hunting. Descriptions of group hunting were scarce for many species and often of insufficient detail for us to be able to classify the level of hunt organisation involved. However, despite this, reports of behaviour fitting the description of collaboration, the most advanced level of hunt organisation, were found in over half the carnivorans reported to hunt cooperatively. There was no evidence that this behaviour would require advanced cognitive abilities. However, there was some evidence that both social mechanisms reducing aggression between group members and information transfer amongst individuals may aid cooperative hunting. In general, the cooperative strategies used seemed to depend partly on the species’ locomotor abilities and habitat. There was some evidence that individuals take on consistent roles during cooperative hunts in some species, but it was not clear if this reflects individuals’ physical differences, social factors or life experiences. Better understanding of the social, cognitive and physical mechanisms underlying cooperative hunting, and indeed establishing to what degree it exists in the first instance, will require more data for multiple individuals and species over many hunts.

Group hunting within the Carnivora: physiological, cognitive and environmental influences on strategy and cooperation

The giving-up density (GUD) framework provides a powerful experimental approach with a strong theoretical underpinning to quantify foraging outcomes in heterogeneous landscapes. Since its inception, the GUD approach has been applied successfully to a vast range of foraging species and foraging scenarios. However, its application is not simple, as anyone who has tried to use it for the first time might attest. Limitations of the technique were noted at its conception, yet only the artificiality of the patches, the appropriateness of the food resource, and the possibility of multiple visiting foragers were identified. Here we show the current uses of GUD and outline the practical benefits as well as the often overlooked limitations of the technique. We define seven major points that need to be addressed when applying this methodology: (1) the curvilinearity between harvest rate and energy, (2) the energetic state of the forager, (3) the effect of group foraging, (4) food quality and substrate properties, (5) the predictability of the patch, (6) behavioral traits of the forager, and (7) nontarget species. We also suggest how GUD experiments can be enhanced by incorporating complementary methods (such as cameras) to better understand the foraging processes involved in the GUD itself. We conclude that the benefits of using GUD outweigh the costs, but that its limitations should not be ignored. Incorporating new methods when using GUD can potentially offer novel and important insights into the study of foraging behavior.

A practical guide to avoid giving up on giving-up densities

Aim Island taxa often attain forms outside the range achieved by mainland relatives. Body size evolution of vertebrates on islands has therefore received much attention, with two seemingly conflicting patterns thought to prevail: (1) islands harbour animals of extreme size, and (2) islands promote evolution towards medium body size (‘the island rule’). We test both hypotheses using body size distributions of mammal, lizard and bird species. Location World-wide. Methods We assembled body size and insularity datasets for the world’s lizards, birds and mammals. We compared the frequencies with which the largest or smallest member of a group is insular with the frequencies expected if insularity is randomly assigned within groups. We tested whether size extremes on islands considered across mammalian phylogeny depart from a null expectation under a Brownian motion model. We tested the island rule by comparing insular and mainland members of (1) a taxonomic level and (2) mammalian sister species, to determine if large insular animals tend to evolve smaller body sizes while small ones evolve larger sizes. Results The smallest species in a taxon (order, family or genus) are insular no more often than would be expected by chance in all groups. The largest species within lizard families and bird genera (but no other taxonomic levels) are insular more often than expected. The incidence of extreme sizes in insular mammals never departs from the null, except among extant genera, where gigantism is marginally less common than expected under a Brownian motion null. Mammals follow the island rule at the genus level and when comparing sister species and clades. This appears to be driven mainly by insular dwarfing in large-bodied lineages. A similar pattern in birds is apparent for species within orders. However, lizards follow the converse pattern. Main conclusions The popular misconception that islands have more than their fair share of size extremes may stem from a greater tendency to notice gigantism and dwarfism when they occur on islands. There is compelling evidence for insular dwarfing in large mammals, but not in other taxa, and little evidence for the second component of the island rule ‐ gigantism in small-bodied taxa.

https://phillimore.bio.ed.ac.uk/phillimore/sites/sbsweb2.bio.ed.ac.uk.phillimore/files/common/Meiri%20et%20al.%202010%20size%20extremes%20%26%20island%20rules.pdf

Slaying dragons: limited evidence for unusual body size evolution on islands

Little is known about how animals acquire and use prior information, particularly for Bayesian patch assessment strategies. Because different patch assessment strategies rely upon distinct capabilities to obtain information, we analyzed whether foragers can alter their foraging strategy when they exploit predictable patches with periodic renewal. For this, we evaluated if learning contribute to increase foraging efficiency by improving patch assessment abilities in degus (Octodon degus), a diurnal caviomorph rodent from central Chile. Single degus exploited pairs of depleting patches that were renewed daily. During the initial two days of the experiment, degus exploited patches in agreement with a fixed-time strategy, i.e. at the population level, giving-up densities (GUD) were not distinguishable from density-independence (i.e. consumption proportional to initial patch densities), and richer patches were under-exploited. After day five, degus improved significantly their assessment strategy, showing agreement with Bayesian information updating. However, on day 15 and afterwards, degus foraged patches in agreement with a prescient strategy, because GUDs across patches indicated positive density-dependence and equalization of GUDs. Although highly variable, the GUD ratio between rich and poor patches decreased significantly throughout time. Within-subject data showed that as subjects learned patch qualities they showed a tendency toward GUD equalization and differentiation from density-independence. By the end of the experiment, degus allocated more time to richer patches during the initial period of each trial, and allocated similar amounts of time by the end of trials. Further, the first visit of a session was significantly biased toward the rich patch by the final days of the experiment. The results suggest that assessment abilities can change when exploiting novel but predictable patches. When degus can incorporate adequate environmental information, prior and current information may become accurate enough to make animals exploit patches efficiently.

On the value of information: studying changes in patch assessment abilities through learning

We estimated the heart and lung size of several species of small bats (Tadarida brasiliensis, Mormopterus kalinowski, Myotis chiloensis, Histiotus macrotus, H. montanus, Lasiurus borealis and L. cinereus) and compared these values to those of bats of larger size and other mammals. Our results confirmed that bats have the largest relative heart and lung size of all mammals. This is associated with the high energetic costs of flight. As expected, the mass-specific lung and heart sizes of small bats were larger than those of large bats. However, although relative heart mass decreased according to body mass, Mb−0.21, lung volume was nearly isometric with body mass (exponent = 0.90). This exponent was close to unity, and between exponents reported previously (0.77 and 1.06). This suggests that small bats compensate the energetic cost of flight mainly by changes in cardiovascular morphology. The relative heart mass of both H. macrotus and H. montanus was particularly large, representing 1.71 and 2.18% ...

Relative size of hearts and lungs of small bats

Birds still share many traits with their dinosaur ancestors, making them the best living group to reconstruct certain aspects of non-avian theropod biology. Bipedal, digitigrade locomotion and parasagittal hindlimb movement are some of those inherited traits. Living birds, however, maintain an unusually crouched hindlimb posture and locomotion powered by knee flexion, in contrast to the inferred primitive condition of non-avian theropods: more upright posture and limb movement powered by femur retraction. Such functional differences, which are associated with a gradual, anterior shift of the centre of mass in theropods along the bird line, make the use of extant birds to study non-avian theropod locomotion problematic. Here we show that, by experimentally manipulating the location of the centre of mass in living birds, it is possible to recreate limb posture and kinematics inferred for extinct bipedal dinosaurs. Chickens raised wearing artificial tails, and consequently with more posteriorly located centre of mass, showed a more vertical orientation of the femur during standing and increased femoral displacement during locomotion. Our results support the hypothesis that gradual changes in the location of the centre of mass resulted in more crouched hindlimb postures and a shift from hip-driven to knee-driven limb movements through theropod evolution. This study suggests that, through careful experimental manipulations during the growth phase of ontogeny, extant birds can potentially be used to gain important insights into previously unexplored aspects of bipedal non-avian theropod locomotion.

/pdf/walking-like-dinosaurs-chickens-with-artificial-tails-2at9a3xxyp.pdf

Walking Like Dinosaurs: Chickens with Artificial Tails Provide Clues about Non-Avian Theropod Locomotion

We analyzed the morphology and the walk–trot and trot–gallop transition velocities of nine juvenile horses and compared them with their mothers. We also compared the relative stride length and the duty factor of the juveniles with respect to adults at three equivalent trotting speeds (Froude numbers 0.5, 0.75, and 1.0), to determine dynamic similarity. Juveniles had a negative allometry in their leg bones, mainly because of little size changes of the distal portions. The negative allometry of extremities allows juveniles to increase stride length without increasing step frequency, which can be biomechanically advantageous. The Froude number during the walk–trot velocity transition of juveniles was similar to that of adult horses, but walk–trot transition velocity in juveniles was greater than expected for their mass. However, during the change trot–gallop, the trot–gallop velocity transition was conserved, but the Froude number was lower. Thus, juvenile horses did not move in a manner that was dynamically similar to the adult horses. At low speed (walk–trot), the gait approaches the behavior predicted by the inverted pendulum model, but at high speed (trot–gallop) dominates the inertial forces. The trot–gallop gait change would be conducted at speeds that would minimize energy costs of transport owing to collisions and changes in the trajectory of the center of mass. J. Exp. Zool. 313A:292–300, 2010. © 2010 Wiley-Liss, Inc.

Comparison of the morphology of the limbs of juvenile and adult horses (Equus caballus) and their implications on the locomotor biomechanics

Comparamos la morfologia alar de ocho quiropteros chilenos, incluyendo dos especies previamente estudiadas. Correlacionamos los hallazgos con la informacion ecologica disponible. Estimamos la razon de aspecto, envergadura, la superficie, y la carga alar del molosido Mormopterus kalinowskii, el phyllostomidae Desmodus rotundus y los vespertilionidos Histiotus montanus, Histiotus macrotus, Lasiurus borealis, and Lasiurus cinereus. Los murcielagos de cola libre, T. brasiliensis, M.kalinowskii y D. rotundus, sin uropatagio, mostraron una baja superficie alar, pero mientras los molosidos mostraron alta razon de aspecto, la de D. rotundus fue solo moderada. Desmodus rotundus mostro la menor envergadura alar, relativa a su masa, y la mayor carga alar. El segundo momento del area del humero de M. chiloensis es menor que lo esperado a partir de las predicciones alometricas, sugiriendo una pobre resistencia a la fuerzas de flexion y a la torsion. Todos los demas vespertilionidos mostraron un alto segundo momento del area, lo que puede ser explicado por su energeticamente costosa forma de locomocion, especialmente en especias con alta potencia parasita a consecuencia de sus largas orejas. El alto Ih que mostro D. rotundus puede ser explicado por su moderada razon de aspecto y por su elevada masa corporal que incrementa el torque producido por el peso. El analisis de componentes principales mostro dos ejes, el primero asociado positivamente con la carga alar y negativamente con la envergadura alar, y el segundo con la razon de aspecto. Se pudieron reconocer cuatro grupos funcionales, uno por cada cuadrante: (1) Desmodus rotundus, con alta carga alar pero baja envergadura, ubicado en la zona de alta agilidad y vuelo rapido con consumo moderado de energia; (2) los molosidos en la zona de alta velocidad de vuelo y bajo consumo; (3) la mayoria de los vespertilionidos en la zona de alta maniobrabilidad y baja velocidad; (4) L. cinereus, con alta velocidad y agilidad. Los grupos funcionales (2) y (3) explotan similares habitat pero con diferentes formas de vida, los molosidos forrajeando en areas abiertas a alta velocidad y los vespertilionidos en areas arboladas con vuelo maniobrable y lento. D. rotundus constituyo un grupo aparte relacionado con sus largos vuelos a sus sitios de descanso y su forma particular de locomocion

/pdf/biomechanical-and-ecological-relationships-of-wing-46g5138ngs.pdf

Bruno Grossi

Papers

On the value of information: studying changes in patch assessment abilities through learning

Relative size of hearts and lungs of small bats

Walking Like Dinosaurs: Chickens with Artificial Tails Provide Clues about Non-Avian Theropod Locomotion

Comparison of the morphology of the limbs of juvenile and adult horses (Equus caballus) and their implications on the locomotor biomechanics

Biomechanical and ecological relationships of wing morphology of eight Chilean bats