There are two sub-orders of the Cetaceans (baleen whales, dolphins, porpoises, and toothed whales):
- Odontoceti (toothed cetaceans)
- Mysticeti (baleen whales)
Some of the main differences between the two sub-orders are:
- Mysticetes have baleen (the stuff they use to filter out krill from the waer when they swallow) and two blowholes whereas Odontocetes have only one blowhole and sharp teeth.
- Another very big difference is how they locate there prey odoncetes locate their pray by echolocation while the mysticetes filter their food into their mouth with baleen.
there are also some major features that are the same:
- All of the Cetaceans bodies are elongated and streamlined.
- There foelimbs have been completley modified and changed into flippers
- They don't have any type of nails.
- They don't have external hindlimbs.
They all have fins though there are many different types of tail, dorsal, and flipper shapes here are some of the different ones and examples of what cetacean they are on:
Tails: V-shaped, Straight, Convex, and Concave (dolphins).
Dorsal Fins: Falcate, Rounded, Hump, Nubbin, Ridge, Finless, and Triangle (Killer Whale).
Flipper Types: Long, Spatulate, Pointy and Tapered (Dolphins), and Paddle like (Killer Whale).
Cetaceans have no external ear flaps, also their skin is usually smooth and sleek although a few species have short bristles on their head areas. Since cetaceans have no external earflaps it is extremely hard to locate where their ears are the location of there ears are right behind the eye on the side of the head, these 'ears' are actually holes the size of a pinhead. Blubber is also a common characteristic that all cetaceans have the thickness, however, depends on the species. This layer of blubber is found directly below the skin.
