Nesbitt Memorial Library Journal, Volume 10, Number 2, July 2000 Page: 70

Nesbitt Memorial Library Journal

ranch and home mammals, a recent study indicated that 21 species of exotic game, mostly
from Africa and Asia, reside in privately-owned fenced compounds within Colorado County.3
Mammalian Response to Human Invasions
Probably, indigenous mammals responded to the human intrusion in one of four
ways: (1) some species were literally hounded out of existence, (2) some were caused to
passively dwindle because they were intolerant to human land-use manipulations, (3) some
were affected only moderately, and (4) a few improved their living conditions and space.
Settlers were quick to hunt, trap, and/or poison large meat-eaters that perhaps
menaced them or their children, and certainly menaced their precious, introduced, domestic
livestock. Thus the big canid and felids (red wolf, jaguar, mountain lion) and the black bear
were dispelled. In addition, beaver, collared peccary, and bison were hunted to extinction
locally, partly, at least, because of their flesh and hides. So was the white-tailed deer, but
even so it "managed" to survive. The reasons for the demise of river otter and the attractive
ocelot are poorly understood, although over-hunting may surely be a factor.
The most striking example of a county species which dwindled because it was
environmentally excluded is, of course, the well-publicized Attwater's Prairie Chicken. It
has failed as a resident because it has been intolerant to pronounced land-use changes in the
quantity and quality of its prairie habitat. Among mammals, the ability of small species (in-
sectivores, rats, and mice) to remain inconspicuous has made evaluations of their responses
to human activities difficult. Decline in the quality and fragmentation of original environment
has, however, definitely triggered the down-grading of more conspicuous populations of
prairie-dwelling black-tailed jack rabbit (Lepus californicus), thirteen-lined ground squirrel
(Spermophilus tridecemlineatus), long-tailed weasel (Mustela frenata), and eastern spot-
ted skunk (Spilogale putorius) and woodland-dwelling gray squirrel (Sciurus carolinensis),
southern flying squirrel (Glaucomy volans), and ringtail (Bassariscus astutus).
The assorted human-initiated environmental manipulations have been compat-
ible, believe it or not, to colonial bats, especially the Brazilian free-tailed bat (Tadarida
brasiliensis) and the big brown bat (Eptescusfuscus). In pre-settlement times these flying
insect-catchers had no spacious caves in the area so used tree holes and space under loose
tree bark as daylight retreats. However, their populations have undoubtedly increased re-
markably by their taking advantage of an array of new harborages in barns, church steeples,
and other abundant man-made structures. In fact, the Brazilian free-tailed bat (the same
species that inhabits crevices in the Colorado River bridge at Austin) occupies attics and
between-wall spaces in many buildings in downtown Eagle Lake.
3 Max S. Traweek, Statewide Census ofExotic Big Game Animals (Austin: Texas Parks and Wildlife
Department, Wildlife Division, 1995).

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