Some animals have a backbone inside their body. Animals with a backbone are called vertebrates. Animals without a backbone are called invertebrates, such as insects, worms and snails.
Five groups of vertebrates
- Mammals — have hair or fur and feed their young milk (cat, cow, human).
- Birds — have feathers, wings and a beak, and lay eggs (eagle, hen).
- Fish — live in water, have scales and breathe with gills (goldfish, tuna).
- Amphibians — live in water and on land (frog, toad).
- Reptiles — have dry, scaly skin and lay eggs (snake, lizard, turtle).
Key idea
Vertebrate = has a backbone. Invertebrate = no backbone. There are five groups of vertebrates.
Example
A cat has fur and feeds its kittens milk, so it is a mammal. A goldfish has scales and gills, so it is a fish. Both are vertebrates.
Remember
- Only mammals feed their babies with milk.
- Only birds have feathers.
- We can sort animals into groups by their features.