2. BIRDS

Those are the characteristics used to define the bird class:

1. They might be herbivorous, carnivorous or omnivorous. We can distinguish it by the beak they have. For instance, hooked beaks help carnivorous to tear flesh; short beaks help herbivorous to peel grain (sparrows); long beaks help birds like hummingbirds to reach the pollen in flowers.

2. They are oviparous, it means that they lay eggs, and those legs must be incubated for a period of time.

3. Offspring are feed by their parents (eagles) or can be independent when they are born (chicks).

4. They are warm-blooded and breathe through lungs.

5. Birds are covered by feathers and have wings.

6. They usually fly and walk, but they can spend long periods of time on the water (ducks, swans). Some birds cannot fly (chicken, ostrich).

7. Scientist recognizes a total of 10,426 species of birds.