Mammal

A whale is a sort of mammal.

A dolphin is a kind of mammal.

A dolphin is a mammal.

The whale is not a fish but a mammal.

The whale is a very large mammal which lives in the sea.

The whale is well known to be the largest mammal.

A whale is a mammal; in other words it feeds milk to its young.

A whale is a mammal.

A whale is no less a mammal than a horse.

A bat is not a bird, but a mammal.