Home | [1–10] << 11 12 13 14 15 16 17 18 19 20 >> [21–30] |
Cleveland, A., Rocca, A. M., Wendt, E. L., & Westergaard, G. C. (2004). Transport of tools to food sites in tufted capuchin monkeys (Cebus apella). Anim. Cogn., 7(3), 193–198.
Abstract: Tool use and transport represent cognitively important aspects of early hominid evolution, and nonhuman primates are often used as models to examine the cognitive, ecological, morphological and social correlates of these behaviors in order to gain insights into the behavior of our early human ancestors. In 2001, Jalles-Filho et al. found that free-ranging capuchin monkeys failed to transport tools (stones) to food sites (nuts), but transported the foods to the tool sites. This result cast doubt on the usefulness of Cebus to model early human tool-using behavior. In this study, we examined the performance of six captive tufted capuchin monkeys (Cebus apella) in a tool transport task. Subjects were provided with the opportunity to transport two different tools to fixed food reward sites when the food reward was visible from the tool site and when the food reward was not visible from the tool site. We found that the subjects quickly and readily transported probing tools to an apparatus baited with syrup, but rarely transported stones to a nut-cracking apparatus. We suggest that the performance of the capuchins here reflects an efficient foraging strategy, in terms of energy return, among wild Cebus monkeys.
|
Cloutier, S., & Newberry, R. C. (2002). Differences in skeletal and ornamental traits between laying hen cannibals, victims and bystanders. Appl. Anim. Behav. Sci., 77(2), 115–126.
Abstract: We compared the size of skeletal and ornamental traits, and asymmetries in bilateral skeletal traits, between victims of cannibalism, cannibals and bystanders within small groups of caged female White Leghorns at the time of cannibalistic attacks (i.e. injurious pecks resulting in bleeding). We hypothesised that victims of cannibalism have discernible morphological traits that predispose them to cannibalistic attack. We predicted that victims would have smaller skeletal traits (body length, ulna length, metatarsus length and width, toe length), lower body weight, poorer body condition, smaller combs and more asymmetrical bilateral skeletal traits than their flock mates. Contrary to our prediction, victims of cannibalistic attacks to the head/neck area (N=23) tended to have larger combs than their flock mates (Wilcoxon matched-pairs signed-ranks test, S=59, P=0.037, NS after sequential Bonferroni adjustment). Their cannibals were more asymmetrical than non-cannibalistic bystanders (metatarsus length, S=48, P=0.011 and composite asymmetry, S=62.5, P=0.002, significant after sequential Bonferroni adjustment). In agreement with our prediction, victims of cannibalistic attacks to other body parts (N=27), including the back, wings, rump, tail, cloaca, abdomen and toes, were more asymmetrical (composite asymmetry, S=78, P=0.022, significant after sequential Bonferroni adjustment) and tended to have lower body weights (S=79.5, P=0.029, NS after sequential Bonferroni adjustment) than their flock mates. Their cannibals did not differ in skeletal or ornamental traits from the non-participating bystanders. The results suggest that large combs either elicit attacks to the head and neck area or increase vulnerability to injury during such attacks. Attacks to other body parts appear to be directed towards birds with signs of weakness relative to their flock mates. In these attacks, there were no distinguishing features separating cannibals from bystanders, suggesting that the bystanders could all be potential cannibals.
Keywords: Domestic fowl; Asymmetry; Skeletal traits; Comb size; Cannibalism
|
Cloutier, S., Newberry, R. C., & Honda, K. (2004). Comparison of social ranks based on worm-running and aggressive behaviour in young domestic fowl. Behav. Process., 65(1), 79–86.
Abstract: Worm-running is behaviour in which a chick runs carrying a worm-like object while flock mates follow and attempt to grab the object from its beak. We hypothesised that social ranks based on worm-running frequency are stable over time and are positively correlated with social ranks based on success in aggressive interactions when older. At 8-12 days of age, we scored worm-running in 17 groups of 12 female White Leghorn chicks during three 10-min tests. Based on instantaneous scans at 5-s intervals, the bird carrying the `worm' most often was placed in rank one and so on down the rank order. These tests were repeated at 68-70 days of age. An aggression index for each bird was calculated as the number of aggressive acts given, divided by the number given and received, during three 1-h observation periods when the birds were 68-70 days. Ranks obtained in worm-running tests were positively correlated over the two age periods (P<0.05) but were not correlated with ranks based on the aggression index (P>0.05). Our results indicate that worm-running ranks are not predictive of success in aggressive interactions. Instead, worm-running fits some criteria for play.
Keywords: Aggression; Social behaviour; Dominance; Play; Chickens; Animal welfare
|
Cloutier, S., Newberry, R. C., Honda, K., & Alldredge, J. R. (2002). Cannibalistic behaviour spread by social learning. Anim. Behav., 63(6), 1153–1162.
Abstract: We hypothesized that social learning is involved in the spread of cannibalism in domestic fowlGallus gallus domesticus . To investigate this hypothesis without harming birds, we used an inanimate chicken model as our cannibalism stimulus. We randomly assigned flocks of 12 White Leghorn pullets to one of two treatments: (1) flocks with two trained demonstrators (N=9) and (2) control flocks (N=8). Demonstrators were trained to pierce a membrane covering a dish of chicken blood and consume the blood. To assess the effect of access to the cannibalism stimulus during demonstrations, we randomly assigned observer pairs to one of two observer treatments: (1) observe stimulus through a wire mesh partition and (2) observe stimulus within the same enclosure. We conducted five 10-min demonstration sessions, each followed by a 10-min test of each observer pair in the absence of demonstrators, over a period of 15 days when the birds were 41-55 days of age, and two further tests at 63-64 and 91-92 days of age. Pairs that observed demonstrators piercing a membrane and consuming blood were more likely to perform this task when tested than control pairs. Learning of the task was enhanced by direct access to the cannibalism stimulus rather than observing it through a wire mesh partition. Blood consumption during tests was increased by direct access to the cannibalism stimulus during demonstration sessions. The birds made bigger holes in the membrane when tested after observing trained demonstrators and after having direct access to the stimulus. Our results provide the first experimental evidence that social learning can contribute to the spread of cannibalistic behaviour in domestic fowl. We suggest that stimulus enhancement and observational conditioning were the social-learning mechanisms involved. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.
|
Colahan, P., Lindsey, E., & Nunier, C. (1993). Determination of the center of pressure of the hoofs of the forelimbs of horses standing on a flat level surface. Acta Anat (Basel), 146(2-3), 175–178.
Abstract: The pressure exerted on a flat level surface by recently trimmed, unshod hoofs of the front limbs of 23 sound, adult horses was measured using pressure-sensitive film and a specially built cassette. The horses were tranquilized and stood with one foot on the 2.9-cm-thick cassette and the other on a block of equal height. The hoofs were observed for motion during the measurement, and the developed film was examined for improper alignment of the film or slipping of the hoof. The center of pressure was located using the method of weighted proportions of Barrey. This static measurement system with a long measurement time and the number of measurements reduced the influence of variables inherent in the horses' behavior and the measuring system. The calculated point was recorded as falling medial to, lateral to or on a line bisecting the central sulcus of the frog. In the dorsal to palmar orientation the point was classified with reference to a line drawn halfway between the most dorsal and the most palmar mark on the film. Forty-six percent of the calculated centers of pressure were located in the medial heel area. Binomial analysis for large samples indicates that this was a significant variation from a random distribution. Seventy-six percent of the centers were located in or on the borders of the medial heel.
|
Collier, T. C., Blumstein, D. T., Girod, L., & Taylor, C. E. (2010). Is Alarm Calling Risky? Marmots Avoid Calling from Risky Places. Ethology, , no-no.
Abstract: Abstract Alarm calling is common in many species. A prevalent assumption is that calling puts the vocalizing individual at increased risk of predation. If calling is indeed costly, we need special explanations for its evolution and maintenance. In some, but not all species, callers vocalize away from safety and thus may be exposed to an increased risk of predation. However, for species that emit bouts with one or a few calls, it is often difficult to identify the caller and find the precise location where a call was produced. We analyzed the spatial dynamics of yellow-bellied marmot (Marmota flaviventris) alarm calling using an acoustic localization system to determine the location from where calls were emitted. Marmots almost always called from positions close to the safety of their burrows, and, if they produced more than one alarm call, tended to end their calling bouts closer to safety than they started them. These results suggest that for this species, potential increased predation risk from alarm calling is greatly mitigated and indeed calling may have limited predation costs.
|
Collins, G. H., Petersen, S. L., Carr, C. A., & Pielstick, L. (2014). Testing VHF/GPS Collar Design and Safety in the Study of Free-Roaming Horses. Plos One, 9(9), e103189.
Abstract: Effective and safe monitoring techniques are needed by U.S. land managers to understand free-roaming horse behavior and habitat use and to aid in making informed management decisions. Global positioning system (GPS) and very high frequency (VHF) radio collars can be used to provide high spatial and temporal resolution information for detecting free-roaming horse movement. GPS and VHF collars are a common tool used in wildlife management, but have rarely been used for free-roaming horse research and monitoring in the United States. The purpose of this study was to evaluate the design, safety, and detachment device on GPS/VHF collars used to collect free-roaming horse location and movement data. Between 2009 and 2010, 28 domestic and feral horses were marked with commercial and custom designed VHF/GPS collars. Individual horses were evaluated for damage caused by the collar placement, and following initial observations, collar design was modified to reduce the potential for injury. After collar modifications, which included the addition of collar length adjustments to both sides of the collar allowing for better alignment of collar and neck shapes, adding foam padding to the custom collars to replicate the commercial collar foam padding, and repositioning the detachment device to reduce wear along the jowl, we observed little to no evidence of collar wear on horses. Neither custom-built nor commercial collars caused injury to study horses, however, most of the custom-built collars failed to collect data. During the evaluation of collar detachment devices, we had an 89% success rate of collar devices detaching correctly. This study showed that free-roaming horses can be safely marked with GPS and/or VHF collars with minimal risk of injury, and that these collars can be a useful tool for monitoring horses without creating a risk to horse health and wellness.
|
Connor, R. C., Smokler, R. A., & Richards, A. F. (1992). Dolphin alliances and coalitions. In A. H. Harcourt, & F. B. M. de Waal (Eds.), Coalitions and Alliances in Humans and Other Animals (pp. 415–443). Oxford: Oxford University Press. |
Connor, R. C. (1995). Altruism among non-relatives: alternatives to the 'Prisoner's Dilemma'. Trends Ecol Evol, 10(2), 84–86.
Abstract: Triver's model of reciprocal altruism, and its descendants based on the Prisoner's Dilemma model, have dominated thinking about cooperation and altruism between non-relatives. However, there are three alternative models of altruism directed to non-relatives. These models, which are not based on the Prisoner's Dilemma, may explain a variety of phenomena, from allogrooming among impala to helping by non-relatives in cooperatively breeding birds and mammals.
|
Connor, R. C., Mann, J., Tyack, P. L., & Whitehead, H. (1998). Social evolution in toothed whales. Trends. Ecol. Evol, 13(6), 228–232.
Abstract: Two contrasting results emerge from comparisons of the social systems of several odontocetes with terrestrial mammals. Researchers have identified remarkable convergence in prominent features of the social systems of odontocetes such as the sperm whale and bottlenose dolphin with a few well-known terrestrial mammals such as the elephant and chimpanzee. In contrast, studies on killer whales and Baird's beaked whale reveal novel social solutions to aquatic living. The combination of convergent and novel features in odontocete social systems promise a more general understanding of the ecological determinants of social systems in both terrestrial and aquatic habitats, as well as the relationship between relative brain size and social evolution.
|