Nutritional Ecol ogy of Mountain Lions 87reduction by harvest. During this time we also were able to document subtle changes
in foraging habits that likely represented how prey use changed with predator popu-
lation size. For example, we confirmed a strong association between mountain lions
and porcupines early in our studies that indicated that lions had significantly reduced
porcupine availability in the Black Hills. Alternatively, Sweitzer (1996) documented
significantly higher predation on porcupines by mountain lions when the primary prey
of lions, mule deer, declined in northwestern Nevada. Therefore, porcupines likely rep-
resent an impor tant prey during initial colonization of areas and later when other
prey become restricted.
One in ter est ing finding related to capture of porcupines was the perceived method
lions used to consume the prey. When necropsying carcasses after lions had consumed
porcupines, we would find whole paws of the prey in the stomach, along with quills,
leg bones, and muscle tissue. It seems that lions removed the paws with their long
nails after orienting the prey on its back (this pattern also was observed for consumed
domestic cats, mink, turkeys, and badgers [D. Thompson, Wyoming Game and Fish
Department, pers. commun.]). From that position, and with the porcupine’s paws
absent, lions then consumed the porcupine from the abdomen, leaving most of the
quills with the skin (fig. 6.8). Nevertheless, when a mountain lion consumed porcu-
pines, quills were found in the lion’s front legs and chest, muzzle, tongue, stomach,
200
150
Mean total kidney fat index100
50
0
2002 2004 2006 2008
Year2010 2012
Female Male2014
figure 6.7. Temporal change in mean total kidney fat indices of male and female
mountain lions from the Black Hills. Note the change in pattern after about 2005
that suggests that total kidney fat declined and was more variable, especially in
females, until 2012. Years 2012–2013 indicate that fat levels became similar to 2005
levels relative to amount and variability between males and females.