|The Mammals of Texas -
Insectivora : Family Soricidae
: Cryptotis parva (Say)
Description. One of the smallest mammals;
snout long and pointed; ears small and concealed in the
short fur; eyes small; tail never more than twice as long
as hind foot; fur dense; upperparts grizzled olive-brown,
paler below. Dental formula: I 3/2, C 1/0, Pm 2/1, M 3/3
X 2 = 30. External measurements average: total length, 79
mm; tail 18 mm; hind foot, 10.5 mm. Weight, 4-7.5 g.
Distribution in Texas. Occurs in eastern
and central portions of the state, west in the Panhandle
to the New Mexico line, and to Val Verde County along the
Habits. The least shrew is an
inhabitant of grasslands where it utilizes the surface
runways of cotton
rats (Sigmodon) and
other grassland rodents. It seldom occurs in forests but
occasional individuals have been found under logs and
leaf litter in moist, forested areas.
Most of its foraging seems to be done
on the surface of the ground but the behavior of captive
individuals suggests that occasionally they may tunnel
through leaf litter and loose, damp soil, much as do
moles, in search of food. The home proper is a small
underground burrow or a series of shallow runways under
flat stones or fallen logs. Burrows excavated in
east-central Texas were about 2.5 cm in diameter, from 25
cm to 1.5 m long, and seldom more than 20 cm below the
surface at the deepest point. Each burrow had an enlarged
chamber at the end or in a side branch for the nest which
was composed of dry, shredded blades of grass. These
nests were used for rearing young or as resting places
for groups of adult and half-grown shrews.
In contrast to most species of shrews, Cryptotis
is sociable, and several individuals may be kept together
in captivity without serious conflict. They sleep
together and cooperate to some extent in digging tunnels
and capturing food. One nest examined in December in
Texas contained a dozen shrews that seemed to be
established there for the winter; another examined near
Nacogdoches was occupied by at least 31 individuals.
These tiny shrews are active at all
hours of the day, but the peak activity comes at night.
Also, they are difficult to trap except in winter when
the supply of natural food is low; then they respond more
readily to bait. In Texas, they tend to concentrate in
favorable areas in winter and to disperse over wider
areas when conditions are more favorable. That they are
abundant at times in favorable areas is attested by the
fact that barn owls capture and consume large numbers of
them. These shrews made up 41% of the food items of a
pair of barn owls as revealed by examination of owl
pellets from Colorado County. In Jefferson County, 73% of
the animals represented in barn owl pellets were Cryptotis.
The food of these tiny creatures is
entirely animal matter snails, insects, sow bugs,
and other small animals. They occasionally set up
housekeeping in beehives and feed upon the bees. Shrews
kept in captivity preferred black crickets, then
grasshoppers, sow bugs, and hard-shelled beetles in the
order named. These captive shrews stored excess food in
one corner of the cage, suggesting that they may behave
likewise in the wild.
The breeding season extends from early
March to late November. No winter-taken specimens from
Texas have been in breeding condition. Females produce
two or more litters each season. The young, three to six
in number, are hairless, blind, and helpless and they
weigh about 0.3 g each at birth. They grow rapidly and
attain adult proportions in about 1 month.
Photo credit: John L. Tveten.