The pair of fins on each side, just behind a fish's head. Pectoral fins help to control an animals direction while moving in the water.

A standard measurement of weight that is equal to a cubic decimeter of water. A 1litre bottle of fizzy drink weighs about as much as a kilogram. A watermelon or pineapple also weighs about as much. The short form of writing kilogram is kg.

An animal (such as a human) that grows fur or hair from out of its skin. The females provide milk to feed their young who are usually born live.

A unit of length that is equal to 1000 metres. It would take an adult about 10 minutes to walk one whole kilometre.

When an animal, such as a bird or turtle moves from one area or habitat to another at different times of year (depending on the seasons).