![]() The hypsodonty index measured in lower molar teeth and the relative length of the lower premolar tooth row indicate that the horse, Equus altidens, was a grazing species, whereas the rhino, Stephanorhinus etruscus, was a mixed feeder in open habitats. ![]() δ13Ccollagen values vary among ungulates: perissodactyls have the lowest values and bovids the highest ones, with cervids showing intermediate values. The range of δ13Ccollagen values for ungulate species indicates that C3 plants were dominant in the diet of these mammals. The combination of these two approaches takes advantage of the strengths and overcome the weak- ness of both approaches. Upon catching up to its prey a bear-dog probably seized it with powerfully muscled forelimbs and killed it by tearing into its ribcage or neck with canines set in a narrow rostrum.Įcomorphological and biogeochemical (trace element, and carbon, nitrogen, and oxygen isotope ratios) analyses have been used for determining the dietary niches and habitat preferences of large mammals from lower Pleistocene deposits at Venta Micena (Guadix-Baza Basin, Spain). ![]() Therefore, bear-dogs probably pursued their prey (mediportal ungulates) for a longer distance but at a slower speed than do living ambush predators. Amphicyon and Ischyrocyon possessed skeletal features of both ambush (short distal limb segments) and pursuit (caudally bent olecranon process of ulna) living predators. Relative grinding area (RGA) of lower molars and wear pattern on upper molars suggest that bear-dogs were carnivorous. This study tests previously proposed models of diet and hunting behaviour of these extinct carnivorans. Interspecific variation in the timing of pursuit-deterrent displays is discussed, as are possible reasons for observed differences in the effect of starting distance.Giant bear-dogs of the genera Amphicyon and Ischyrocyon (Carnivora, Amphicyonidae, Amphicyoninae) were the largest carnivorans in North America during middle and late Miocene (17.5–8.8 Mya) with a dental and skeletal morphology that combined features found in living Ursidae, Canidae, and Felidae. Display distance and flight initiation distance were identical in the data set analyzed, but individuals sometimes perform tail displays prior to fleeing. Starting distance did not affect escape behaviors, presumably because it did not affect perceived risk, but might do so at a faster approach speed. As predicted by escape theory, flight initiation distance and distance fled were greater and refuge entry was less probable at greater distance from refuge, indicating that qualitative predictions of escape theory apply to pursuit deterrent signalers. ![]() I also investigated whether starting distance (distance between predator and prey when approach begins) affects escape behaviors. I studied effects of the risk factor distance from refuge on flight initiation distance, distance fled, probability of entering refuge, and the distance between predator (an approaching human) and prey when pursuit-deterrent display begins (display distance) in the Cuban curly-tailed lizard ( Leiocephalus carinatus). Although the function of pursuit-deterrent signaling is to dissuade predators from attack, relatively little is known about relationships between specific components of escape and the signaling behavior. Several aspects of escape behavior are predictable by escape theory based on expected costs due to predation risk and escaping.
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