Copyright © 2007 Dorling Kindersley
Sounds, signals, and gestures make up an animal’s LANGUAGE, and are essential to survival. The method of communication often depends on how close together the animals are. Sound is effective over long distances and in the dark, whereas body language and light are visual signals that are generally used at close quarters. Smell is used to communicate breeding times and to indicate territorial boundaries. Animals usually communicate with members of their own species using a code that only they can understand.
Wolves live in social groups called packs, consisting of a dominant male and female and their offspring. They communicate using body language, sounds, and scent. They use their ears, tails, and facial expressions to convey dominance and submission depending on their position in the pack. Wolves whine to greet one another, and howl to let others know they are there.
When they are afraid, chimps open their lips but keep their teeth together, rather like a forced smile. Chimps use this expression when they are approached by a chimp of higher rank.
When chimps pout with their mouths slightly open, they are indicating submission to a higher-ranking chimp, possibly after a dispute of some kind. They may whimper at the same time.
An open mouth suggests excitement. Young chimps use this face when they are playing. It is accompanied by grunts and screams. The more excited the chimps, the louder the grunts are.
Many animals in the deep ocean, ranging from squid to plankton, produce shimmering light to communicate. This light is referred to as bioluminescence. Some animals produce it themselves in organs called photophores. Others have sacs of bacteria in their skin that produce light. Animals use light to find mates and food, for defence, and camouflage.
Dolphins are highly communicative and make many noises, despite the fact they have no vocal chords. The clicks, squeaks, whistles, and trills that dolphins make are made by muscles in their blow hole – the hole on the top of the head through which they breathe when they come to the surface.
Capybaras of South America live in family groups. The dominant male has a large scent gland on the top of his nose, called a murillo. He rubs it on objects to mark the boundaries of his territory and to warn off intruders. The scent message remains until he returns to remark the spot. Many animals communicate through scent.
Jane Goodall has been studying the behaviour of chimpanzees for over 40 years. She was the first person to record that chimps make and use tools, a skill previously attributed only to humans. Her study methods – monitoring a family of chimpanzees in their natural environment – revolutionized research on ape behaviour.
Unlike human language, animal language is not dominated by vocal signals. They use combinations of behaviour to talk to one another. Some animals communicate using high- and low- frequency sounds, which humans cannot hear, while others communicate using light that is invisible to people. Some animals use smell to communicate with one another.
Elephants produce many sounds, including some that humans cannot hear. These low-frequency rumbles travel over long distances through the air and under the ground. Elephants detect the vibrations with their feet and the tip of their trunks. These sounds may explain how lone male elephants find females and how family members communicate when they are a long way from each other.