Blue whales feed mainly on krill. Whales eat different foods depending on where they live. During the summer months, whales eat about 4 tons of food every day. Blue whales that live in the waters of the waters of Lower California and Mexico are known to eat red crabs.
The blue whale is a representative of baleen whales, instead of teeth it has a mustache.
The mustache hangs from the upper jaw. They consist of keratin, a material similar to the nails, then turn into thin hairs in the mouth next to the tongue. The whale takes a very large amount of water in the mouth, and then releases it back. When water is expelled from the mouth, the whalebone plates act as a sieve and delay food.