The Online Library of Knowledge

Animals

How animals feed

A hawkmoth drinks nectar from a flower A hawkmoth drinks nectar from a flower Most animals take food items into their bodies through an opening, the mouth, to be digested and absorbed inside. Many animals eat mainly plants, or plant parts such as leaves, fruits, seeds, nectar, shoots and roots. These are called herbivores. Other animals eat the flesh of other creatures (sometimes their whole bodies). These are called carnivores, or, if the other creatures are insects, insectivores. Some animals, including some worms, insects, lampreys and the vampire bat, feed on blood. A few animals eat a wide range of both plant and animal food: they are omnivores. Finally, detrivores, such as dung beetles and crabs, eat dead or rotting food and wastes.

Lion and cub eating a Cape buffaloLion and cub eating a Cape buffalo

Vampire batVampire bat

Mouths

There are almost as many different sizes and designs of animal mouth as there are different kinds of food. Most mammals, like ourselves, have teeth that can bite smaller pieces from a large food item and then chew the pieces into a soft pulp that is easily swallowed. But some mammals have few teeth—or none at all. The anteater collects its tiny food items of ants and termites by flicking out its long, sticky tongue.



The vampire bat has front teeth like razor blades but it only uses them to slice a slit in its victim’s skin. Then it uses its tongue to lap up its meal of blood.


The treecreeper probes for insects. The treecreeper probes for insects. Birds lack teeth, although they can peck powerfully with their strong, horn-covered beaks. Some birds have long, thin beaks like tweezers for probing into cracks or mud for small food items. Others have deep, short, powerful beaks that work like nutcrackers, for splitting seeds and nuts. A few species, such as the blue-footed booby, have serrated (teeth-like) edges to their beaks that help them grip on to fish, for example.

Most frogs have teeth but they cannot chew with them: they are usually only good for gripping prey before swallowing it whole.

Some animals do not feed at all. The mayfly fed when it was a larva. But the adult form has no mouth and cannot eat. It mates and dies within a day or two of pupating.

© 2019 Q-files Ltd. All rights reserved. Switch to Mobile