Animals: identifiable by their characteristic four legs, animals are probably the most famous creatures available. Meat comes from here.
Sea creatures: includes sharks, crocodiles, whales, barnacles another fish. Distinguished from animals by bing slimy and more suited to parsley sauce.
Sea monsters: the most fearsome class, sea monsters vary widely. The common theme about them is that when you tell people about them, they assume that you are lying. A fascinating fact: zombies are technically in this category although none of them live in the sea!
Birds: anything with wings. Birds evolved when the earth was still covered in lava and therefore too hot to walk around on.
Fungus: mushrooms, toadstools and athlete's foot. If you go for a walk in the woods and see a fungus, why not eat it? It's a proven scientific fact that a creature that doesn't move can't hurt you.
Any creatures that don't fit these classes are the exceptions that prove the rule.
From: The wit and wisdom of the Pirate Captain - a major philosophical work. Gideon Defoe.