Wednesday, May 23, 2012

Wild World Wednesday ~ All About Dolphins

Ever since the fist dolphin was placed into captivity these adorable sea creatures have been a fan favorite. This started way back in the 1870's when sea animals would be found injured and brought back to aquariums to be rehabilitated. It wasn't until the late 1930's that Hollywood started using captive dolphins for movies and later started training them. Today there are more than 3000 Bottlenose dolphins in aquariums around the world.

Let's take a closer look at these marvelous creatures and discover what makes them so special.

The Blowhole Nose

Dolphins are not able to breathe through their noses as most animals do, they have what is called a blowhole instead. This crescent-shaped, muscular flap is on top of their heads and can be sealed off when the dolphin is diving or under water. Even though the dolphin has total control of its blowhole it must surface for air, but it takes only 0.3 seconds for it to exhale and inhale. Some dolphins are able to hold their breath for as long as 30 minutes. Like our human noses the blowhole of the dolphin is a direct passageway to its lungs.

Another function of the dolphins blowhole is used for communication. Because this mammal doesn't have vocal cords the blowhole pushes air back and forth through air sacs in the "nasal passages." Tissue know as the "phonic lips" vibrate to make the dolphin talk - a series of clicks, chirps, whistles, squeaks, moans, grunts, and creaks.

Half Asleep

As humans we automatically breathe without thinking about it, however, dolphins do not have this ability. So how does a dolphin sleep? First off, dolphins don't fall into a deep sleep like you and me, if they did they would drown. When the dolphin needs to rest it will float in a shallow pool of water or float just under the surface. When it has found a safe, comfy area, the dolphin then lets one side of it's brain sleep, while the other stays awake to continue breathing.

More Dolphin Facts

~ Dolphins live in family groups of 10 - 12
~ The best known dolphin it the Bottlenose
~ There are 36 kinds of sea dolphins and 5 species of river dolphins
~ Dolphins are mammals (warm-blooded) and give birth to their babies live as well as nurse them with milk
~ Dolphins use echolocation to find food
~ Dolphins eat fish and squid and will sometimes hunt in groups
~ Dolphins can leap from 15-30 feet into the air
~ Dolphins are not fish. They need to breathe oxygen from the air as we do.

For more information on dolphins, visit your local library or an aquarium such as Sea World.

Wonder Words
~ rehabilitated; restore to life or useful state
~ echolocation; determining the location of something by measuring the time it takes the echo to return from it.

Here's a fun activity, print and colour your very own dolphin. Click here for Dolphin Colour Page

For more fun articles and cool stories, check out knowonder magazine for kids ~ It's totally FREE;


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