Whales and dolphins are warm-blooded mammals that are virtually hairless and nurse their young; hair and nursing are a defining characteristic of mammals. They have adapted to the sea and look like fish but they have bones like other mammals. They are streamlined which allows them to swim easily. It is this streamlined appearance that has caused humans to mistaken whales for fish throughout history.

These sea-adapted mammals have some unique features that other mammals do not have. For example, when scuba diving, humans cannot dive too deeply or too long; we will get the "bends" In a dive, pressure on the body increases and nitrogen in the pressurized air we breathe while diving dissolves into our blood stream and tissues. If we dive too far down or stay under for too long, too much nitrogen will be dissolved into our bodies. If we surface too quickly, the nitrogen forms bubbles in our blood.

Diving

When whales and dolphins dive, they hold their breath which means they do not have to dissolve pressurized air into their bodies. Scientists believe that they may exhale as they dive so that they have less air in their lungs to be dissolved. Their lungs actually collapse from the pressure as there isn't a supply of air to pump them up. They store a large amount of oxygen in their bodies, which is one of their special diving features. Cetaceans are also able to shunt blood to parts of the body that do not need a constant supply of oxygen.

Whales and dolphins do not have a difference between the outer and inner ear. Instead of sound passing through the outer ear to middle ear, they receive sound through their lower jaw. And, this helps them to dive better.

Social behavior

Some cetaceans are highly social and live in large and complex pods, while others are solitary and form groups only for short periods of time. The social complexity of whales and dolphins are not widely understood by scientists.

They are placed in a classification of predator but some are more aggressive than others. Their food can range from plankton to large fish.

Breaching

Noteworthy behaviors include breaching and tail slapping. While leaping may not seem so noteworthy with dolphins or smaller whales, it is particularly impressive, from a physical perspective, for a large whale such as the humpback.

A humpback lifts its fifteen-meter bulk into the air, which is like raising the equivalent of nearly 500 people at a speed of 15 knots and uses the energy equivalent of 2.6kg (6 lbs) of fish. One humpback was reported to breech 130 times in 75 minutes. A quick calculation from the above formula results in 330kg (740 lbs) of energy.

Although humpbacks may be seen leaping on the feeding grounds in cold temperate waters, this activity appears to be more common in the breeding grounds in the tropics.

Some scientists believe that the whale is trying to rid itself of parasites by slapping its body against the water's surface. Others think that the humpback may be trying to impress a female during mating season

Ballena Marine National Park has a great whale watching season from December through March when the whales migrate through this park.

Other behaviors

When a cetacean raises its head almost vertically out of the water for a short period of time, scientists call the behavior spyhopping. The term originated with whalers, who believed that the whales were spying as they peered above the water.

When a cetacean raises its flukes and slaps the water's surface, this is known as lob tailing or tail slapping. This is thought to show irritation or to be an aggressive display, at least in humpback whales, bottlenose dolphins and orca whales.

Having fun

Dolphins are known to speed along in front of a boat and push ahead of it through a pressure wave of water are bowriding. In the right position, a dolphin can stop swimming and be pushed along. This behavior may be learned by young dolphins as they are pulled along in the current created by their swimming mothers. The reason for bowriding is not clear, but it may represent a behavior of other mammals — the desire to play!