80 Mountain Lions of the Black Hills
because the animal was bored. These subadult lions, however, were thin, with low fat
levels. One such observation was of a subadult male that died on Interstate 90 where
a herd of elk commonly crossed the highway. It is pos si ble that the male was in pur-
suit of these elk and was killed by a vehicle when attempting to cross the road.
The lion had consumed a few blades of grass but nothing more.
One nutrient need that differentiates cats from other predators is the need for the
amino acid taurine (Hedberg, Dierenfeld, and Rogers 2007). This nutrient aids in the
development and functioning of the eye and, thus, the development of sight in cats. If
deficient in taurine, kittens can become blind and/or develop sight- related prob lems.
Concentrations required for normal development and function range between 0.04%
and 0.2% of the diet, and intake is generally adequate when the animal consumes
whole prey, such as rodents (Hedberg, Dierenfeld, and Rogers 2007). When we first
documented cloudy- eye syndrome in mountain lions, we believed that the population
was saturated. If lions at some saturation level have difficulty capturing prey because
of reduced availability or begin consuming what might be considered low- quality prey,
then, we hypothesized, taurine availability could become compromised and could
lead to subsequent eye or sight- related prob lems. However, we were unable to link
this disease with taurine availability or determine the disease vector responsible for the
condition. The relationship between nutrition and disease for large free- ranging feline
carnivores has yet to be evaluated.
We collected data on nutritional characteristics of mountain lions in the Black Hills
from late 1999 through mid-2013. We worked closely with the South Dakota Depart-
ment of Game, Fish and Parks, which at times received calls regarding kittens that
had been abandoned, either owing to harvest, removal of an adult female, or death of
the mother caused by vehicles or natu ral causes. When kittens were extracted from
the wild, they would be transported to our departmental captive fa cil i ty at SDSU
(fig. 6.1). While they were in that fa cil i ty, we would periodically collect information
on body weight and age; the South Dakota Department of Game, Fish and Parks worked
to place the kittens in zoos accredited by the Association of Zoos and Aquar iums. We
generally held captive lions less than about seven months, a period that allowed for
collection of data and scheduling of transport to zoos. Over the time of our work
(2003–2012), we placed kittens in zoos located in vari ous cities, including Philadel-
phia, Salt Lake City, Kansas City, Denver, and Phoenix. While raising these kittens, I
discussed appropriate foods for young cats with zoo personnel, who strongly sug-
gested that these animals receive adequate taurine from dietary fish or some other
component.
Information collected on captive kittens was combined with data on wild kittens
of known age (up to 1 year) to estimate the rate of gain in weight for young lions in
the Black Hills (fig. 6.2). Based on the combined data, we found that body weights of
young lions can increase between about 0.50 kg and 0.62 kg per week (n = 29 kittens)
in the Black Hills. Captive data were less variable than data on wild lions that were