Animals - Fish
3 groups:
- jawless: no biting jaws, but sucker disks with a rasping tongue and small teeth made of keratin. The lampreys (七鳃鳗) are the only jawless fish.
- cartilaginous: skeleton made of cartilage instead of hard bone. Most are predators with sharp senses. Sharks and rays: most fish are bony, but sharks and rays have skeleton made of springy cartilage.
- bony: have a hard bony skeleton and a swim bladder.
Fins
- lobe fin: fleshy fins, used to "walk" on the seabed or riverbed
- ray fin: most fish belong to this group. fins are supported by a fan of jointed rods called rays.
Species
- Sturgeon 鲟. Caviar is made from the eggs of the sturgeon.
- mudskipper: can survive out of water by absorbing oxygen from the air through its skin.
鲨鱼
鲨鱼是鱼,不是哺乳动物。鲨鱼用鳃呼吸,鲸鱼用鼻子呼吸,鲨鱼是冷血动物,鲸鱼是温血动物,鲨鱼全身有盾鳞,鲸鱼皮肤光滑没有鳞片。
Basking shark: the world's second largest fish, after the whale shark. Feed by swimming with its vast mouth gaping wide.
Ray
- Giant Manta ray: the biggest ray. Can leap out of the water when trying to avoid large predators.
- Batoidea 鳐总目,又名魔鬼鱼;Rajiformes 鳐形目;Ray 鲼;Stingray 魟; 鲼形目=燕魟目; Mobula 蝠鲼
- Manta ray has the largest brain of fish