Graduation Year


Graduation Month


Document Type


Degree Name

Bachelor of Science

School or Department

Wildlife Biology


Wildlife Biology – Terrestrial

Faculty Mentor

Mark Hebblewhite

Faculty Mentor Department

Wildlife Biology

Faculty Reader(s)

Mark Hebblewhite, Hugh Robinson, Jedediah Brodie


cougar, mountain lion, kill rate, kleptoparasitism, predator, functional response

Subject Categories

Biology | Zoology


Kill rate, defined as the number of prey killed per predator per unit time, is a key component to understanding predator-prey dynamics. A multitude of factors may affect kill rates, including, variation in age, sex, weight, or presence of offspring of either predator or prey species (intraspecific variation) and events such as the theft of a kill made by another animal (kleptoparasitism). These factors may influence the time a predator spends locating prey (search time) and the pursuing, killing, and consumption of prey (handling time). The sum of search time and handling time may be measured as the time between a subsequent kill, a metric I will use to make inferences on what affects mountain lion (Puma concolor) kill rates. Utilizing kill data obtained from Global Positioning System (GPS) collared mountain lions of Colorado, Wyoming, and Patagonia, I investigated the impacts of: 1) mountain lion sex, 2) mountain lion age, 3) accompaniment of offspring with mountain lion females, 4) prey weight, and 5) the presence of bears (habitual kleptoparasites) throughout study periods. Applying these factors, I determined the most parsimonious and biologically sound statistical model, best describing sources of variation in time between kills for mountain lions. Determinant factors were: age of a mountain lion, in which a juvenile (old) was predicted to killed less often than an adult (>2 years old); presence of offspring, in which a female with accompanying offspring was predicted to kill more often than a mountain lion without; per kg of prey weight, in which time between kills was predicted to increase as the weight of a prey item increased; and based on bear activity, in which a mountain lion was predicted to kill more often when bears were active on the landscape than when they were not active. Further knowledge on this subject may be useful for harvest management of mountain lions regarding the lessening of impacts of predation on ungulate populations of concern, through age class and reproductive status targeting. Furthermore, I show some evidence of the indirect impacts of kleptoparasitism on ungulate populations, through the direct impacts on kill rates of predators such as the mountain lion from kleptoparasitic bear species.

Honors College Research Project




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