Whales are mammals that live underwater. Like all mammals, they breathe air and they are born live from their mothers instead of coming from eggs. However, whales are also unusual mammals, and not only because they live underwater. They are also unusual because of the types of teeth they have (or lack). Most mammals have teeth to help them bite and chew their food, making it possible to feed themselves. Scientists group all whales into two categories: toothed whales and baleen whales. As the names suggest, one type of whale has teeth. The other type has something very different, called baleen, instead of teeth.
Toothed Whales: How They Eat
Toothed whales (or "odontocetes") are so named because of the teeth in their mouths. However, a whale's teeth look very different from human or even dog teeth, for that matter. Most toothed whales have cone-shaped teeth. A toothed whale also uses its teeth very differently than most other mammals. Usually, the whale doesn't use its teeth to chew. Instead, it often eats its food whole. Some toothed whales, like the narwhal, only have a single tooth. Toothed whales with very few teeth often eat squid, which they can suck down whole, without any chewing at all.
All About Toothed Whales
Toothed whales include many well-known whale species, including dolphins, killer whales (or "orcas"), sperm whales, pilot whales, and beluga whales. The biggest difference between toothed whales and baleen whales is, as the names suggest, their types of teeth. However, toothed whales also have some other unique qualities that make them different from baleen whales. Toothed whales are usually smaller than baleen whales, though there are exceptions, such as the enormous sperm whale. Toothed whales are predators, meaning that they hunt for their food. Toothed whales might eat seals, fish, or sea lions. Toothed whales also often live together in groups, called "pods." By living together in groups, toothed whales can work together to hunt for food. Some species, such as the orca or "killer whale," have even been seen hunting sharks and humpback whales.
How Baleen Whales Eat
Baleen whales include many of the largest whales in the sea, such as the blue whale. Instead of teeth, baleen whales have a substance called a "baleen plate." Since they have this plate, they must hunt and eat their food differently than toothed whales do. The hunting method that baleen whales use is sometimes called "filter feeding." The whale's baleen plate is shaped much like a comb or a sieve. Because of this plate, the baleen whale can catch food simply by swimming toward the prey with its mouth wide open. The bristles of the baleen let water pass through while trapping the whale's prey. Usually, these enormous animals eat thousands of very tiny animals, including small fish, krill, shrimp, and various crustaceans. Once the whale's food is caught on its baleen plate, the whale can bring it into its mouth with its tongue, much like when you lick your lips!
All About Baleen Whales
The baleen "comb" or plate is not the only thing that sets baleen whales apart from toothed whales. They also live very different lives, usually swimming alone instead of with a group. In some cases, baleen whales may join together when they migrate, or swim long distances. They may also become more social during mating periods. Since baleen whales are very large and have thick layers of blubber, a kind of body fat, they are capable of living in extremely cold waters. Even though baleen whales are so large, they actually have very small throats, making it uncommon for them to eat large fish, squid, octopus, or other underwater animals.
Of the 80 to 90 species of whales under the sea, they may be divided into two main groups. To know whether a whale belongs to one group or the other, the first place to check is the teeth. However, having different types of teeth also means different eating habits and a different lifestyle and overall shape, or "physiology." As a result, toothed and baleen whales actually have many differences, including how they look, how large they grow, and how they behave.