Page 34 - Mammal (DK Eyewitness)

Fast breeders Bodies have
no fur

Mice are small, relatively defenseless
mammals. They are easy prey for many
other creatures. Their strategy for
survival is to breed at an
extraordinary rate. A female house
mouse starts to breed when she is
six weeks old and can have up to
10 litters in a year, with about five
to seven babies in a litter. If all the
young survive and breed in turn, one pair
of mice may become half a million mice!

Developing tail Nest made of Tiny limbs
straw and grass

BIRTH DAY
T
1 he mouse mother has built a cozy nest of
woven straw, grass, moss, and other plant pieces.
Around human habitation, house mice may use bits
of shredded cloth, burlap, or paper. The nest is made
in a safe place such as down a hole, under
floorboards, or behind a wall. About 20 days after
mating, the mother gives birth. The babies are
barely recognizable as mammals, let alone mice -
pink, hairless, earless, and blind - and are totally
dependent on their mother.

TWO DAYS OLD
T
2 he wriggling, rubbery babies divide their time
between taking milk from mother (suckling, pp. 36-37)
and resting in the cozy lining of the nest. Their tails are
lengthening and their eyes and ears are becoming
more prominent.

Ear flaps

FOUR DAYS OLD
3After two more days, the
babies are beginning to
resemble mice.
Their ear flaps are
visible and their
limbs and feet have
taken on more mouselike
proportions. They make
squeaks audible to us and
also ultrasonic squeaks, too
high to be heard by the human
ear. The mother can hear them,
of course. If she leaves the nest
for too long and the babies get
RETURN OF THE WANDERER cold, they will call to her
The mouse is a good mother. She ultrasonically, as if asking “Please
locates babies who wriggle or fall come and warm us up!”
from the nest, partly by following
their squeaks, and will carry them
by mouth back to safety. Toes have developed
32

(c) 2011 Dorling Kindersley. All Rights Reserved.