Whales are marine mammals. This means they are warm blooded, give birth to live young, and breath air just like their land mammal counterparts. However, they are built for life in the ocean. There are many different species of whales, each with unique adaptations to thrive underwater. Whales can be divided into two groups: Mysticetes and Odontocetes. These two groups diverged from each other about 30 million years ago.
The group mysticetes consists of baleen whales. Baleen whales are filter feeders. They use their baleen plates, long comb-like structures that hang from their top jaw, to trap massive amounts of food at a time. Krill, plankton, and small fish are gulped into their large, inescapable mouths. The blue whale is the largest type of baleen whale, and also the largest animal to have ever lived on earth. They can grow up to 98 feet long, and weight up to 187 tons. The blue whale can eat over 3 tons of krill a day using this filter feeding method.
The group odontocetes, a more diverse group, includes toothed whales, as well as dolphins and beaked whales. This group has more complex social systems and are usually found in pods. Sperm whales are the largest of the toothed whales, and they have the largest brain of any animal. They can grow up to 59 feet long and weigh up to 45 tons. Sperm whales can dive up to 3,000 feet while hunting for a meal of fish and squid.