Whale Anatomy

The anatomy of whales, dolphins and porpoises all share several common and unique characteristics that allow them to survive and prosper in the various ocean environments where they can be found.

Like other mammals these marine animals require oxygen to breathe, eyes to see and ears to hear.

Unlike other mammals however whales, dolphins and porpoises have flippers, flukes, a dorsal fin and blowhole(s) that make navigating the ocean much easier.

This article will give you a basic understanding of a cetaceans anatomy and help you understand why these physical adaptations are so important for their survival.


Whales, porpoises and dolphins are  marine mammals and like all mammals they require oxygen to survive.

Unlike other sea creatures such as fish a whale would suffocate in water if it did not have a blowhole for oxygen.

The blowhole is situated on or near the top of their head and acts as an airway passage for breathing.

Whales cannot breathe through their mouth because the esophagus (food passage) and trachea (oxygen passage) are completely separated from each other.

Although whales must breathe oxygen they can spend up to 90% of their lives underwater.


Toothed whales are typically smaller than baleen whales (whales without teeth) and have a single blowhole on their head as compared to the two blowholes found on a baleen whale.

Their teeth can vary greatly among each of the species, and some may not even use their teeth for eating.

Some whales such as the sperm whale are believed to use their teeth mainly to show aggression.

Instead of enamel which is found in humans a whales teeth is covered in cementum cells.

Unless the cementum is worn down you won’t be able to see the enamel on their teeth.


Baleen whales have rows of baleen plates that resemble the teeth of a comb located on the top of their jaws instead of teeth.

The bristles act as a filter allowing water to escape their mouth but being packed tightly enough to keep fish and crustaceans trapped inside.

Dorsal fin

The main purpose of the dorsal fin is to stabilize the whale and keep it from rolling in the water.

Some whales/dolphins such as the killer whale have a dorsal fin while others such as the beluga whale do not.

Fins can also vary greatly in shape and size depending on the species of whale.

Almost all whales have a dorsal fin with the exception of a few species such as the sperm whale and beluga whale.


The flippers on a whale or dolphin are used to navigate and steer in the ocean.

They use their flippers to perform various aquatic acrobatics such as steering left and right by changing the angle of their flippers and use their flippers to provide lift so they can rise in the water and control their level of aquatic depth.

The flippers are controlled by strong pectoral muscles and can vary in size with each species.


The flukes are attached to the end of the whale/dolphin and are used for propulsion.

Unlike sharks however whales and dolphins move forward by flexing their tail up and down, not left and right.


The eyes of a whale are relatively small when compared to the rest of its body.

Their eyes are well adapted to aquatic life and secrete an oil used to lubricate and protect their eyes from debris and other chemicals in the ocean.

They are not capable of secreting tears as humans do, but their cries can be heard vocally from many miles away.


The ears of a whale or dolphin are designed differently than a humans ears and are well adapted to marine (aquatic) life.

For a whale/dolphin there is little difference between the inner and outer ear area.

Instead of receiving sound through the outer ears whales receive sound through their throat, the sound than passes through a cavity and into the inner ear.

Bonus: Whales can vary greatly in terms of weights and size. The dwarf sperm whale for example only grows to a length of about 9 ft. and weighs up to 600 pounds while the blue whale can grow to over 98 ft. and weigh up to 150 tons!