There are two kinds of whales - toothed whales and baleen whales. Baleen whales have big mouth but no teeth. Instead they have baleens.
Baleens look like the teeth of a comb.
Which hang from the upper jaw. Blue whale is a baleen whale. It is about 100 feet long. Right whale, Gray whale are all baleen whales. Baleen whales eat lots of small animals called krill.