FIND OUT MORE. Biology 72 • Life on Earth 70–71
Nature^97
HOW DO ANIMALS DEFEND THEMSELVES?
Animals behave in many different ways to escape
danger. Some are camouflaged to blend in with their
surroundings. Behaviour such as keeping still
completes their disguise. Some species defend
themselves with more complex behaviour, such as
pretending to be injured or dead. Hedgehogs and
armadillos roll into a ball to ward off predators.CLOWNFISH 3
Clownfish hide from their
enemies among the
stinging tentacles of sea
anemones. The fish’s skin
releases chemicals that stop
the anemone’s cells from firing.
Clownfish are found in
tropical seas around
the world.HOW IMPORTANT IS INSTINCT?
Instinct plays a major part in the
behaviour of animals, especially animals
that are not reared by their parents. For
example, when danger threatens, snails
instinctively withdraw inside their shells. Animals also
learn by trial and error, repeating actions that are
productive and abandoning ones that are not.1 PUFFERFISH
Pufferfish defend themselves by
inflating their bodies with water.
Along with their spines, this
makes them harder for bigger
fish to swallow. Many other
species are also covered with
spines to protect them from
even the largest of predators.WHY DO ANIMALS FOLLOW REGULAR CYCLES?
All animals follow regular cycles to help them survive.
Many creatures are active by day, when their senses
work best. Others come out at night to avoid
predators, or take advantage
of feeding opportunities.
Most animals also follow
yearly cycles, usually bearing
young when food is abundant.2 IMPRINTING
Baby birds such as goslings (young geese) instinctively follow the first
animal they see after hatching. This is usually their own mother, but
goslings have also been known to waddle around after humans and dogs.BEHAVIOUR
In order to survive, all animals must eat and
avoid being eaten. They are also driven to
reproduce so their species does not die out.
Most animal behaviour is geared to these
basic goals. Some behaviour is learned,
the rest is controlled by instinct.