The Marine Friends Project :: Life in the Ocean ::

LIFE IN THE OCEAN

When you’re watching whales on television, or reading about them in a book, or on a whale watch boat, ask: What would it be like to live in the ocean?

Whales, the largest ocean animals are very much like people we both belong to a category of animals called mammals. We give birth to live young. We breath air. Our bodies keep our internal organs (stomach, heart, liver) warm so that they will function properly.

But imagine living in the cold ocean waters. Or diving so deep that the pressure of the water can crush your organs! What changes would you have to make to survive if you lived in the ocean?

First how would you keep warm? You and I put on extra layers of clothing. Whales, dolphins, and seals put on an extra layer too. But their layer is beneath their skin. They have a layer of fat, called blubber, that acts as insulation, in the same way that your down parka keeps you warm in the winter. Down does not transmit the cold; neither does the layer of blubber. On some whales, that blubber layer can be 8 to 10 inches thick!

Second how can you breath? Fish breathe by taking oxygen from the water through their gills. But whales and dolphins are not fish; they don’t have gills. They breath air, the same as we do. They have blow holes on the top of their heads. When you look closely at a whale as it comes to the surface of the water, it opens its blow holes to breathe.

You and I can hold our breath for only a short time. Eventually our systems force us to take a breath we can’t hold our breath any longer. That’s because our organs need to constantly get fresh oxygen. Blood carries oxygen to our muscles and our organs.

But whales and dolphins must hold their breath for many minutes so that they can dive down deep where they find their food. Their bodies have changed in several ways to let them breathe less often than we do. First, they have special blood cells that can carry more oxygen than our blood cells can. Second, their blood vessels have special reservoirs that can store blood carrying oxygen until it is needed. And third, they have a special substance in their muscles that stores oxygen and releases it while the animals are making their long dives.