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Home
Main Sections of Website
The Liza's Reef Project |
This page is intended to
only be an introduction to endangered cetaceans of our world. Links at the bottom of the
page will take
you to some of the best resource sites out there for more in-depth information. The
best sites to start with are marked with a star
Dolphins and Porpoises belong to the families Delphinidae and Phocoenidae, with the dolphins the largest and most diverse family, one that includes 26 species. They possess a distinct beak and most species of dolphins are larger than porpoises. Porpoises belong to a rather small family which consists of only six species. They have no distinct beak and their foreheads slope uniformly to the tip of their snout. Both types of cetaceans are carnivores, and their sleek streamlined shapes are perfectly adapted to high speeds in the ocean. Bursts of up to 25 miles per hour have been recorded. Dolphins and porpoises are able to achieve such high speeds by leaping from the water in a series of dives and spending as little time as possible under the water, a technique known as "running". The life cycle of dolphins and porpoises is similar to that of other cetaceans, and they bear their young alive. Nursing lasts between one and a half to two years, and the mother will remain with her calf for a period between three and eight years. Most species tend to bear one calf every other year, and dolphins and porpoises have an average life expectancy of around thirty years.
Dolphin and porpoise brains are about the same size as humans, and they possess an amazing ability to learn and imitate. Much has been written about their intelligence and the consensus in the scientific community is that have a level of intelligence compare to humans. In hunting for prey, dolphins and porpoises use their developed sense of hearing in a very sophisticated way known as echolocation, a process whereby they emit a steady series of rapid "clicks" through their blowholes. These outgoing clicks bounce off objects, similar to radar, and a portion of the signal is reflected back to the dolphin for analysis. Through this process, they are able to determine the distance to a school of fish or other prey by measuring the time between emitting and returning clicks. This allows these amazing animals to hunt prey over great ranges in which visibility is limited. Dolphins feed mainly on schools of prey and as a result most species have developed cooperative hunting practices which are much more efficient than hunting alone. |
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Another phenomena associated with many
whales, especially the Blue Whale and the Humpback Whale, are the
haunting songs they sing. Researchers are not sure why whales sing,
although it is thought their singing is associated with breeding, and
keeping in contact with each other over vast ocean distances. Whales are the largest animals that have ever lived on earth, including the dinosaurs. The largest is the blue whale, which can grow to almost 100 feet in length, the height of a 9-story building. These enormous animals eat about 4 tons of tiny krill each day, obtained by filter feeding through their baleen. The smallest is the dwarf sperm whale which grows only to just over 8 feet long.
Whales exhibit a number of unusual and characteristic behaviors -breaching, spyhopping, lobtailing and logging. Breaching is jumping high out of the water and then slapping the water as they reenter. Occasionally they twirl around while doing this spectacular move. In spyhopping the whale pokes its head out of the water and turns around, perhaps to look. Some whales also stick their tails out of the water, swing it around and then slap the water's surface with it. This is known as lobtailing. It may be done as a warming to the rest of the whale group, or pod, as a warming. Logging is resting on the surface of the water, with the tail hanging beneath. While floating motionless like this, part of the whale's head, dorsal fin and back are exposed. Cetaceans exhibit very strong social ties, with the strongest being between the mother and calf. A social group of whales is referred to as a pod. Mysticet (baleen whales) travel alone or in small pods, and Odontoceti (toothed whales, which include dolphins and porpoises) travel in large, frequently stable pods. These toothed whales also hunt their prey in groups, migrate together and share care of the young.
Official, Scientific & Governmental Sites
Discovering Whales
Marine Mammal Commission
National Marine Mammal Laboratory: Whales, Dolphins and Porpoises
NOAA's Office of Protected Species: Whales, Dolphins and Porpoises
The Porpoise Page
Ultimate Guide To Dolphins
WDCS Whale and Dolphin Conservation Society
Welcome To The Watery World Of Whales
Whale Center of New England
WhaleNet
Whales Online
Wild Animal Watch: Dolphins
ICUN World Conservation Union
United Nations Environment Programme World Conservation
Monitoring Centre
US Fish & Wildlife Webpages on Endangered Species
ANON -Act Now For Ocean Natives
American Cetacean Society
Cetacean Society International
Save The Whales
Surfers For Cetaceans
The Oceania Project: Caring For Whales, Dolphins & The Oceans
The Original Dolphin Project
CANADA, BRITISH COLUMBIA
Wild Whales
SCOTLAND
Dolphins & Seals of the Moray Frith
BOTTLENOSE
DOLPHINS:
HUMPBACK WHALES:
PINK RIVER
DOLPHIN:
Aquatic Adventures
Whale Watch.com
Whale Watching Web
Dolphins Plus
Dolphin Research Center
Aqua Thought Foundation
Charlotte, The Vermont Whale
Dolphins and Man......Equals?
Earthtrust Hawaii's Marine Wildlife: Dolphins
Marine Mammal Stranding Center
Songs of the Whale
Whale Songs
David's Whale & Dolphin Watch
Professor David Ulansey's Website -Mass Extinction Underway
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