Page 35 - Mammal (DK Eyewitness)

SIGN OF THE MAMMAL
Fur starts Feeding the young on
to appear milk is a unique
mammalian trait, and
the mother mouse feeds
her babies regularly. This
gives them the energy
they need to grow at
such an amazing rate.

Eyelids
are open

SIX DAYS OLD
4The youngsters take on a house-mouse brown as
their fur appears. This is a risky phase, since their
movements and their squeaks are becoming more
forceful, and so their nest is in greater danger of
being found by prowlers. The mother continues to
suckle; her offspring will not be weaned (off milk and
onto solids such as seeds and grains) until they are
about 18 days old. The father is long gone. He takes
little or no part in family life.

TEN DAYS OLD
5The eyelids are now open and the young mice can see, although
they are nearsighted creatures. They are also more mobile, with
increasingly coordinated movements. In many mammals, the young
would have reached this stage of development in the womb, and
they would now be born (see the kittens on pp. 34-35).
However, mice rely on large litters to keep up their
numbers, so the young are born in a premature
state, since the mother would be unable to carry
so many big babies in her womb. Body is covered
with fur

FOURTEEN DAYS OLD
6The mice are now becoming
curious about their surroundings
and leave the nest for short
periods. In a few more days the
young mice will be ready to
make their own way in
the world. Soon they
will face hazards
alone, such as
predators, lack of
food, exposure to At two weeks old
the elements - and over- mice start
crowding as they exploring away
themselves begin to breed. from the nest

Nest is now
too small

33

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