56 Mountain Lions of the Black Hills
and thus provides but a snapshot rather than a pattern of how litter size might have
changed temporally. Nevertheless, litter size determined from placental scars aver-
aged 3.33 ± 0.48 kittens based on a sample of 30 females (B. Felts, SDSU, unpublished
data). This average was similar to the 3.0 kittens per litter estimated by Jansen (2011).
Furthermore, this sample indicated that first breeding of females occurred around
2 years of age and that litter size increased from about 1.0 to 5.0 kittens at 4–7 years
of age.
Dispersal
During the period from 2003 to 2006, information we were collecting on this pop-
ulation suggested that mountain lions inhabiting the Black Hills were becoming
“saturated” (i.e., exhibiting density- dependent effects [Thompson 2009]). Others who
have studied large mammals, including mountain lions, have documented movements
out of populations, especially when they approach carry ing capacity. This pro cess of
dispersal (movement out of a population without return [Thompson and Jenks 2010]) is
impor tant to maintain ge ne tic transfer among mountain lion populations via immigra-
tion and emigration (Sweanor, Logan, and Hornocker 2000; Culver et al. 2000; Ander-
son, Lindzey, and McDonald 2004) and to reduce strife among competitive individuals
(Logan and Sweanor 2001; Maehr et al. 2002). Maehr and colleagues (2002) suggested
that lions exhibit a “frustrated dispersal,” which is predominately exhibited by males,
but some females also move away from family members.
Generally, this dispersal movement is more than a home range away from family
members, which could be problematic for lions in the Black Hills, considering the
rather small width and length of the region and previously documented dispersal dis-
tances for the species (up to 224 km at the time [Maehr et al. 2002]). Yet, inexperi-
ence with the prairie habitat surrounding the Black Hills could represent a barrier to
figure 4.10. Comparison of 1.5- year- old (left) and 6.5- year- old (right) reproductive tracts
of female mountain lions. The arrow points to a placental scar (previous attachment of
placenta). Photos by Brandi Felts.