Page 40 - Mammal (DK Eyewitness)

Growing up

Compared to other animals, mammal parents invest a
lot of time and energy in their young. An insect may lay
hundreds of eggs and leave them to their own devices. A sea
urchin casts thousands of eggs into the water and has
nothing more to do with them. Mammals adopt a different
strategy. In general, they have only a few offspring, but they
look after them well. The young are cleaned, fed, kept warm,
protected, taught, and generally cared for until they are self-
sufficient. The degree of parental care varies, however, within
the mammal group. We are at one end of the spectrum:
human parents spend many years raising their children. The
mother tree shrew is at the other end - she leaves the young
in a nest after birth and returns only once every couple of HELPLESS AT SIXTY-THREE DAYS OLD
days. The female cat looks after her kittens until they are While the young cat has become self-sufficient,
a human baby of the same age is relatively
weaned and old enough to feed themselves. Kittens grow helpless. One of its most rewarding behaviors is
rapidly, as these pictures show, getting the energy they need to smile, which encourages affection and
handling (and so warmth) and strengthens the
for growth from their mother’s milk (p. 36). By nine weeks mother-baby bond. But it will be many more
old the kittens have grown enough to leave their mother. years until it is fully independent.
Compare this with the wallaby (p. 30) and the mice (p. 32).

Newborn kitten BIRTHDAY
1Kittens have their fur at birth. But living in the watery environment of the
womb makes the baby look waterlogged. The water is amniotic fluid. (p. 34).
The mother licks her offspring thoroughly and the fur is soon dry and shiny.
Eyes and ears The kitten is relatively helpless: it cannot see or hear (the eyes and ears are
are closed closed), and it cannot lift its head. But it can feel and smell, and push itself
along, so that it soon finds the mother’s teat and begins to feed (p. 36).
Fur has dried

Seven-day-old kitten SEVEN DAYS OLD
2In a week, the kitten has doubled its weight from the 3.5 oz (100 g) or so
at birth. Its eyes are just beginning to open. They cannot yet detect colors
and shapes; these are just a jumble at first. The kitten must learn to
Body length recognize and make sense of what it sees, and this takes time. The mother
has increased cleans it and licks up urine and feces. In the wild this is sensible behavior,
because a soiled and smelly nest would soon attract predators.

Eyes are Twenty-one-day-old kitten
small slits

TWENTY-ONE DAYS OLD
3By now the kitten’s eyes and ears are
functioning well, and it can hold its head up. Its
weight has quadrupled since birth, muscles are
now stronger and more coordinated, and the
legs are a bit longer, so that the youngster can Eyes fully open
just about creep along in a shuffling manner. If
the kitten is in trouble it mews loudly, showing
the first or “milk” teeth that appear between
the age of two and three weeks.
Milk teeth
Legs are longer allowing
creeping movement

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