Animals often use sound to communicate with each other. Sound is a fast method of communication and, unlike chemical stimuli, it leaves no lingering trace of the animal after the stimulus has been given out. Sound, however, has the limitation that it can only travel between 30 and 40 metres in the air (although it has a greater range in water - humpback whales use sound to call each other over several kilometres).

Sound is, however, a useful stimulus over short distances when sight and touch are impossible, such as for insects in tall grass. The male grasshopper rubs his back legs together to create a shrill noise to attract females. The females have two membranes, one on each of their front legs, which act as their "ears". Since other insects also use sound as a method of communication, each species has its own pitch and duration of notes.

Johnny's Fact File No.47 Dolphins have a range of 20 different sounds.

This is also true for many species of frogs and toads which gather together at night in pools and lakes during the mating season. The males call to their females and the females must be able to receive and identify the sound made by the males of their own species.

Mammals which live in groups, such as mongooses, use different sounds to communicate different types of information. In general there are two main types of sound - one type which serves to bring the individuals of the group together, and a another set which act as a warning signals and serve to disperse the group.

The hedgehog is an insectivorous mammal which makes a variety of noises such as snorts, grunts, puffs, coughs and screams. 

The hedgehog has excellent hearing, a marvellous sense of smell and, in common with all insectivores, a very sensitive nose. Its eyesight, however, is only moderately good and there is evidence that it only sees the colour yellow. Hedgehogs are. solitary animals and will fight with each other if they meet. Unfortunately, and perhaps because of its poor eyesight, the hedgehog will also attack brushes and brooms that have been left in a garden.

In 1913 experiments were carried out in Vienna using a relatively new invention, the telephone. The sound of a male cricket was transmitted over the telephone. The receiver was in the same room as a group of female crickets. 

The females all moved towards the telephone as the sounds of the male cricket were heard. This experiment proved that the female crickets will react to the stimulus of sound alone; they do not need to see or smell the male.

Whales make underwater sounds which can last for many hours. Each whale has a different pattern of sounds and it is thought that these sounds are important in the identification of individuals.

Johnny's Fact File No.48 The great tit uses more than 50 different sounds. The short, simple calls act as alarm calls and are often used to communicate between the parents and their young.

• Homepage:The Effect of Stimuli on the Behaviour of an Organism
• Chemical stimuli
• Visual stimuli
• Touch
• Chapter Summary (useful for revison)
• Questions relating to this chapter
• Top of Page

© Paul Billiet, Shirley Burchill, Alan Damon and Deborah James 2009