Prey Carcasses Research Articles

Response by wolves to prey variation in central Ontario

The influence of variation in prey availability in a wolf–moose–deer–beaver predator–prey community was studied from 1987 to 1992 in Algonquin Park, Ontario, Canada. Density, food habits, and movements of 57 radio-collared gray wolves (Canis lupus) were compared among three regions of varying moose (Alces alces) and white-tailed deer (Odocoileus virginianus) spatial and temporal abundance. Relative moose and deer availability was determined annually from 16 track surveys (5 km each), 150 pellet surveys (300 × 2 m), stratified aerial surveys (2 or 3 each winter), and prey carcass data. One region contained high moose abundance and virtually no deer year-round. The second region had high moose levels with moderate levels of deer, and a third region varied in deer winter abundance annually. Wolf use of deer was high, based on the proportion of deer in winter scats (9.3–32.1% frequency of occurrence; 4.3–22.5% total biomass) and the number of deer predation cases (50 carcasses) that occurred in all three regions, even in areas where deer were considered to be very rare. Wolf use of deer was positively correlated with increases in winter deer abundance (r2 = 0.66). Wolf density correlated with deer numbers (r2 = 0.74). In winter, deer in the third region migrated to a deer yard 15 km from Algonquin Park. A remaining overwintering deer density of less than 0.02/km2appears to have prompted a movement of wolves to the deer yard. Of the 41 moose consumed by wolves in winter, most (71%) were scavenged animals that had died with infestations of winter tick (Dermacentor albipictus). Beaver (Castor canadensis) apparently acted as important buffer prey species when deer numbers were low. The Algonquin wolf's reliance on smaller prey items appears to be a function of the fluctuating prey base, which promotes alternative hunting strategies, and the small size of the Algonquin wolf, which makes it an inefficient predator of moose. Even though moose were relatively constant in availability, and a major food item, the wolf population was responding primarily to the availability of deer.

Prey bone utilization by predatory dinosaurs

Many mammalian predators chew and crush bone to various degrees during their utilization of a prey carcass, leaving tooth marks on the prey bones as evidence of their activity. Recognition of similar types of tooth marks on dinosaur bones provides a means to evaluate the degree to which predatory dinosaurs were capable of prey bone utilization. A survey of 858 dinosaur prey bones from six dinosaur localities in Wyoming, Utah and Montana, has shown the frequencies of tooth-damaged bone range from 0.0% to 4.0%. Compared to bone assemblages in which there is a strong inference of mammalian scavenging, the frequencies of tooth-marked bone from the dinosaur localities are decidedly less common. Theropod dinosaur feeding behaviors were probably more similar to Komodo monitor behavior observed in the monitor communities of Indonesia, than for mammalian-based communities. The results of this survey indicate that bone crushing was not employed by predatory dinosaurs during their utilization of prey carcasses. The routine crushing of bone, then, as a means of obtaining further nutrients contained within a prey carcass was not an ecological or functional phenomenon present in the Mesozoic and was only developed later by mammalian predators in the Cenozoic.

Feeding economy of larvae of a flower fly,Metasyrphus corollae [Dip.: Syrphidae]: Partial consumption of prey

Metasyrphus corollae (F.) larvae ingested aphid contents at a decreasing rate over time because the contents of the aphid became increasingly difficult to obtain as the body of the prey was emptied. Starved larvae usually handled prey longer than wellfed larvae. Younger starved larvae fed longer than older larvae. Larvae starved for 24 h ate the most of a prey. Larvae held prey, on average, until 71% of dry mass was extracted after which the prey carcass was discarded. Prey handling time and amount of each prey consumed were determined by size and hunger of larvae and degree of depletion of prey contents.

A guide for differentiating mammalian carnivore taxa responsible for gnaw damage to herbivore limb bones

Large cats, canids, bears, and hyenas create distinctive types of damage when they gnaw bones. This paper describes the diagnostic characteristics of damage done by each taxon to femora and tibiae of herbivores whose body weights are 300 kg or more. Pleistocene and Recent fossil collections that include gnawed bones might provide data on the presence of carnivores whose own remains are not found in the collections. Information might also be gained about predator and scavenger utilization of prey carcasses, often a reflection of prey vulnerability or availability in past communities.

Caching Behavior of Brown Bears (Ursus arctos)

Caching and complete covering of prey carcasses by the brown bear ( Ursus arctos ) is known from a wide area of its distribution and was first recorded from Norway in 1599. Examination of 16 sites of cached sheep in south-central Norway showed no preference for topography, soil, forest type, or plant community. In one instance a sheep was cached under water in a small brook. In some cases two or more sheep were cached at the same site, associated with the killing of 10 sheep in a restricted area. Some caching sites were circular, some oval, and some irregular in shape, and varied in size from 3.5 to 75 m2 ( X = 43 m2). Volumes of scraped material were calculated to 0.5–1.5 m3, but some piles may have been even larger. Numerous bear scats at the caching sites and the presence of beds nearby indicated that bears resided near the sites for a considerable time. The combined guarding and caching behavior may be explained by the slow consumption of prey by bears and their intake of considerable plant material while foraging on a carcass. The adaptative significance of caching in the brown bear may be to reduce decomposition and to hide the carcass from competitors.

The biophysics of pit construction by antlion larvae ( Myrmeleon, Neuroptera)

An antlion pit is lined with fine particles during construction. This feature appears to increase the effectiveness of the pit in prey capture. Pit structure is influenced by physical properties of sand and the building behaviour of the antlion. Two physical properties of sand govern pit structure: the angle of repose and Stoke's Law drag force. These two properties complement each other as follows: (a) Since larger particles have a lower angle of repose than smaller particles, fine sand grains tend to stay on the pit walls, whereas larger particles fall to the pit's centre. (b) Large particles have a lower drag to momentum ratio than do small particles. Thus, larger particles are more likely to be thrown out of the pit than are smaller particles. Several behavioural modifications were demonstrated that increase the number of fine particles on the pit walls while reducing construction costs for the antlion. (a) A trajectory angle of 45° is used when the antlion throws particles out of the pit. This angle will maximize the distance to which larger particles are thrown. A trajectory angle of 60° is used at the end of pit construction when the antlion is throwing fine particles on the sides of the pit. This angle reduces the number of these fine particles leaving the pit. (b) Antlions can alter the velocity with which they throw particles. When discarding prey carcasses and debris that have accumulated during prey capture, they use a velocity that is approximately 39% higher than the velocity used during pit construction. (c) By vibrating their forelegs, antlions appear to sift out the finer particles before each throw. This increases the percentage of larger particles discarded from the pit.

Bait-and-capture strategy of a termite-eating assassin bug

Salyavata variegata is a Reduviidae found on the carton nests ofNasutitermes corniger in Costa Rican rain forests. Nymphs capture termite workers at repair sites after attracting them into vulnerable positions with the empty carcasses of previous prey.

Utilization and Skeletal Disturbances of North American Prey Carcasses

More than 125 carcasses and skeletal remains of wild bison, moose, and whitetail deer were examined in the field. Most were from closely documented episodes of predation, mass drownings, or other natural causes of death. Predictable and unusual kinds of bone and carcass utilization by timber wolves and bears are described. The variables emphasized include sectioning of carcasses by feeding predators, distribution and dispersal of bones at kill sites, gnaw damage to bones in homesites, kill sites and scavenge sites, potential or observed survival of bones at sites of prey carcasses, and the patterns of scatter or accumulation of skeletal remains in moose and bison ranges due to predation or other natural causes of death. Variations in gnaw damage to bones and utilization of carcasses by carnivores reflect significant aspects of predator-prey interactions, and can be deciphered by ecologists interpreting either fossil or modern assemblages of bones.Key words: carnivores, prey carcasses, taphonomy, North America, paleoecology, archeological interpretation

Predatory Behavior of Yellow Baboons

Abstract1. A group of 32 yellow baboons (Papio cynocephalus) in the Masai-Amboseli National Park, Kenya, caught and ate 45 vertebrate prey items during 2519.19 hours of observation. 2. Eighty percent of the prey items were mammals and the most frequently eaten species were African hares (Lepus capensis), vervet monkeys (Cercopithecus aethiops) and neonate gazelle (Cazella granti and G. thomsoni) in that order. The details of predatory behavior for each prey species are described. 3. Rates of predation were significantly higher during the long dry season than during other months of the year, although no correlation was found between total monthly rainfall and monthly rates of predation. A lognormal model however provided a good fit to the monthly rate of predation data suggesting that the rate of predation by Amboseli baboons was affected by several factors that acted multiplicatively with respect to each other and were themselves related to rainfall or dryness. 4. A mean of 2.3 individuals fed directly from the carcass of each prey item. A mean of 3.5 individuals per prey item fed directly or indirectly, i.e., on scraps, from each carcass. In general, both the number of individuals who fed from each carcass and the duration of their feeding bouts was dependent upon the gross body size of the prey item. Adult males fed directly from the carcass of prey items for about three times more minutes than expected from their number in the group; other classes of individuals fed directly from prey carcasses for only one-fourth as many minutes as expected. In general, an adult male would be expected to feed on each category of vertebrate prey at least once per year, while individuals of all other age-sex classes would be expected to feed on most prey categories only once every two years. 5. The most frequent social behavior around prey items was agonistic bouts; no cooperation, simultaneous feeding or specific begging gestures were observed. 6. Estimates of the total number of prey killed annually by Amboseli baboons indicate that baboon predation probably has a negligible effect on prey populations other than vervet monkeys. 7. It is speculated that the need for vitamin B12 underlies baboon predatory behavior, and perhaps that of other primate species as well.