79My experience with wildlife nutrition began at the University of Maine, where I worked
under the direction of Dr. David M. Leslie Jr. and raised deer fawns to assess the ef-
fects of digestibility of poor- quality winter diets on their nutrition. Then, while work-
ing on my PhD, I evaluated how cattle affect the nutritional condition of free- ranging
deer in Oklahoma and Arkansas (Jenks and Leslie 2003). At the time, the techniques
I used for deer were rarely evaluated in carnivores, likely because of the low number
of carcasses available for assessing nutritional condition. However, those techniques
were beginning to show up in the lit er a ture, and relationships being documented for
the more common deer species were similar to those for, for example, the wolf (Canis
lupus) (LaJeunesse and Peterson 1993). It seemed, therefore, a logical extension to eval-
uate nutritional condition in mountain lions when carcasses began to increase in
frequency in the Black Hills.
Mountain lions are true carnivores, in the sense that they consume only meat and
associated carcass components (bones, cartilage, fat). Because of their monotypic pro-
clivity for diets high in protein, their requirements for nutrients differ from those of
pseudocarnivores, such as coyotes and bears, which seasonally consume high amounts
of fruit or other non- protein- rich food sources (for the coyote, see MacCracken and
Uresk 1984; for the black bear, see Mosnier, Ouellet, and Courtois 2008). Using stan-
dard procedures for evaluating diets, it is rare to document a lion that has consumed
foods other than what are considered standard prey sources. For example, a young male
that has become in de pen dent from its mother and has thus begun to disperse may de-
part from the usual diet. In this situation and on a few other occasions, we have docu-
mented mountain lions consuming some vegetation. However, we were unsure whether
the vegetation (pine needles, a few blades of rough grasses) was consumed while
grooming, or because the animal had not eaten for an extended period of time, or
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