Dolphin popularity: |
| There is a lot to like about dolphins. They
leap dramatically out of the water and re-enter with a satisfying splash. They make
endearing squeaks and click sounds. Many of their fascinating behaviors, performed during
presentations at zoos and aquariums all over the world, are a reflection of their natural
behaviors in the wild. But even with their great popularity, there are still a lot of
things most people do not know about dolphins. |
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What dolphins are:
Dolphins are mammals (not fish!), although they do not really resemble the furry, land
varieties we are most familiar with, like dogs, tigers, rabbits, people, etc. But dolphins
meet all the requirements to be a mammal they are warm-blooded, they produce milk to
nourish their young, and they have hair. Hair? Where? Dolphins have hair for a few months
after they are born, then they lose it for good.
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Life in the water:
Part of the reason that aquatic mammals like dolphins look so different from their
land-mammal relatives is that life in the ocean presents different challenges for survival
than life on land.
Dolphins are well adapted to the ocean. They have a smooth, streamlined body for easy
movement through water. They move their flat tails, called flukes, up and down to propel
themselves. Their pectoral (side) fins do the steering. The dorsal fin on top provides
stability as the dolphin cuts through the ocean at up to 20 miles per hour.
Dolphins also have a special kind of camouflage that works well in water, protecting them
from predators. Their bodies are dark gray on top, and their sides are lighter gray. Their
belly is the lightest of all, usually white or faint pink. When seen from above, dolphins
blend in with the darker depths of the ocean. From below, their light underside matches
the sky.
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Groupies
Bottlenose dolphins are social animals, living in groups throughout
their lives. The groups may fluctuate in size, from a pair of dolphins to more than
fifteen. The group’s make-up changes, too. For example, mother dolphins will form
groups with other female dolphins. Together, the females share the duties of raising their
young. Sometimes juvenile dolphins get together, and it is in these groups that young
dolphins learn the rules of dolphin society.
Catching fish is best accomplished in groups, too. Some members of a group will drive fish
towards shore and catch them, while other dolphins hang back to prevent fish from making a
dash for open sea. By cooperating, individual dolphins increase their chance of getting
something to eat.
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Whistle while you fish
As social animals, dolphins need to communicate with each other in
order to hunt efficiently, raise their young, and guard against predators. Because it
travels through water so readily, sound is the most important form of communication among
dolphins. Each dolphin has his or her own unique "signature" whistle. These
whistles announce a dolphin’s identity and location, even when he or she is well out
of eyesight. Signature whistles are produced in a dolphin’s forehead, or
"melon." The melon is also the source of high-pitched sound waves that help
dolphins catch fish. Dolphins find fish using "echolocation," bouncing
click-like sounds off the fish and giving dolphins the exact location of their future
meal.
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Just the facts
Length: 8 to 10 feet
Weight: 250 to 600 pounds
Distribution: The Atlantic coast from Virginia to Florida and into the Gulf of Mexico
Habitat: Primarily along coasts in temperate and tropical waters
Wild diet: Fish, crustaceans, and squid
Brookfield Zoo diet: Fish, such as herring and capelin, and squid
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Content
from Brookfield Zoo |
Play
the Brookfield Zoo Dolphin Game |
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Photos
of Dolphins from the web. . . |
