my care2
make a difference

community & fun

groups

get together & make a difference

 
 
 All About Dolphins May 14, 2007 10:00 AM

species river dolphins 5 species sperm whales 3 species beaked whales 19 species beluga and narwhal 2 species porpoises 6 species
The dolphins that we are studying in the Indian River Lagoon are bottlenose dolphins and they belong in the subgroup of oceanic dolphins.

What's the difference between a dolphin and a porpoise?
Even though they are both toothed whales, they have different body shapes. Dolphins usually have a large forehead. The easiest way to tell them apart is to look at their teeth. All dolphin teeth are round when you cut them in half. All porpoise teeth are flat.




Dorsal Fin, Flipper, Fluke What are flippers and flukes?
The front limbs on a dolphin are called flippers. The bones inside the flippers are similar to the bones inside your arm and hand. Bone and Cartilage Dolphins don't have any hind limbs. The dolphin's tail is called its flukes (each half is a fluke). There are no bones in a dolphin's flukes, just tough connective tissue. The dolphin uses its flukes for swimming and its flippers for steering. Most dolphins have a boneless dorsal fin in the middle of their back that works somewhat like the rudder on a boat. Like the flukes, the dorsal fin does not contain any bones.

Are all dolphins the same color?
Dolphin body color is highly variable. Some, like the killer whale, are strikingly black and white. Other dolphins — like the pilot and false killer whales — are almost solid black. The bottlenose dolphin is usually some shade of gray, but it is much lighter on its belly than on its back. This kind of coloring may help camouflage dolphins in the water. Looking down on them, the dark colors blend in with the ocean. Looking up from underneath, the patches of light and dark skin blend in with the sunlight coming through the water.

How big do dolphins grow?
The biggest dolphin is the killer whale. Killer whale calves are about 8 feet long at birth and can grow to over 20 feet long. Bottlenose dolphins are about 3 1/2 feet long at birth and grow to 8 or 9 feet long.

Size Diagram Adult Dolphin

     Please stay tuned for the next installment.....

 [ send green star]  [ accepted]
 
 May 14, 2007 8:20 PM



Dolphins Swimming Where do dolphins live?
All over the world — from colder northern and southern waters to warm tropical waters. The bottlenose dolphin prefers warmer water.

How fast do dolphins swim?
We don't know how fast most dolphins swim but bottlenose dolphins typically swim at 3 to 7 miles per hour. They can go over 20 miles per hour when they work hard. The body shape of a dolphin helps it swim fast. A dolphin's body is shaped like a tube that is pointed at both ends. This streamlining helps the water flow over the dolphin's body as it swims.

How deep do dolphins dive?
It's hard to say how deep oceanic dolphins can dive because most of the 32 species have not been studied. Bottlenose dolphins are shallow divers and typically don't go deeper than 150 feet. In the Indian River Lagoon the deepest waters are only 10 to 12 feet deep.

How do dolphins stay warm?
Even though dolphins are warm-blooded, and their internal temperature is about 98 degrees, they need to conserve their body heat in colder water. Like most whales, the dolphin's body is surrounded by a thick layer of fat (called blubber) just under the skin that helps keep the dolphin warm.

What do dolphins eat?
Mostly a variety of fish and squid, depending on what part of the ocean they live in. The bottlenose dolphins in the Indian River Lagoon eat mostly fish because there aren't many squid in the lagoon. A dolphin's cone-shaped teeth interlock to catch fish. Their teeth are not used to chew, and they swallow their food whole.

 [ send green star]  [ accepted]
 
 May 16, 2007 9:59 AM

How do dolphins communicate?
Just like dogs, cats, and other mammals — by using sound, vision, touch, and taste. Dolphins don't have the ability to smell, however. Scientists do not think that dolphins have a language like humans. Each dolphin can make a unique signature whistle that may help individual dolphins recognize each other, but it may just help a dolphin know that some other dolphin is nearby. Scientists don't know for sure. Wave file (169K)
QuickTime file (181K)

To echolocate, the dolphin generates a sound pulse (of clicks) in its forehead which is sent into the water. EcholocationThe sound bounces off objects, creating an echo that returns to the dolphins. We think that dolphins hear the returning echoes by feeling the sound pulses against their jaws. Different objects (like different kinds of fish) give off different kinds of echoes. Dolphins can also judge how far away the object is by the amount of time it takes for the echo to return.

Wave file (119K)
QuickTime file (63K)

 [ send green star]  [ accepted]
 
  New Topic              Back To Topics Read Code of Conduct

 

This group:
WHALES & DOLPHINS
153 Members

View All Topics
New Topic

Track Topic
Mail Preferences


Copyright © 2009 Care2.com, inc. and its licensors. All rights reserved