The following two suborders of Cetacea are separated on the presence of baleen plates or teeth.
TOOTHED: The conical teeth of toothed whales are used to seize and hold pray, such as large fish, squid, and even seals, but not for chewing. They vary in size and number: there are 160 in the bottlenose dolphin and 50 in the lower jaw only of the largest of the toothed whales, the sperm whale. BALEEN: Baleen whales have a comb of thin plates called baleens in place of teeth. They feed by straining small, shrimp-like creatures called krill or plankton that are found near the surface and occur in schools, enabling them to capture large quantities of prey through their baleens. The horny plates of the baleen whales are arranged along either side of the upper jaw, like the pages of a book, with the inner side frayed out into bristle-like fibres. This filter feeding in baleen whales are used to sieve zooplanktonic organisms. The minke whale has the shortest baleen, around 3 feet (less than 1 m) in length and numbering 230-260. The 500 silky, bristly baleen of the southern right whale are among the largest, at around 13 feet (4 m) long. TINY TO TITANIC Whales can grow to an enoumous size because they are buoyed by water and need not support their own weight. Fast swimming predators, such as dolphins, benefit from their compact, streamlined form, they rarely exceed 1.2-1.5m (4-5 ft) in length, such as the Hector's Dolphin, known to be one of the smallest of dolphins. The large size of baleen whales, such as the blue whale measuring at 110 feet (33 m) in length, the largest living animal on earth, gives metabolic advantages for living in cold seas. Blubber up to 20 inches (50 cm) thick conserves heat as blood flows to the skin is reduced. The smallest (hector's dolphin) and the largest (blue whale) of the cetaceans are also both endangered.  REPRODUCTIONSome whales, including rorquals (rorquals have grooves on their throats), breed durng the winter. They migrate from their summer feeding grounds in polar seas to tropical waters, usally around islant groups or close inshore), where they give birth and then immediately become pregnant again. In spring they return to colder waters to feed. Other whales may breed seasonally, but do not migrate to do so. After giving birth, the mother (and in some dolphins other members of the pod) assist the newborn to the surface to take is first breath. FEEDING Baleen whales tend to migrate to summer feeding areas, growing to enormous sizes and feeding on small plankton. While the gray whale feeds on small crustaceans called amphipods (which are found on the sea bottom), right whales and rorquals eat planktonic crustaceans, which live near the surface. Rorquals are more active hunters and usally surround their prey. As they feed, the grooves in the troat are relaxed, and the lower jaw becomes a vast sac into which water is gulped. When the water is expelled, the prey remain on the baleen plates. The larger species of rorquals have finer bristles on their baleen plates, which trap crustaceans such as krill and sometimes small fish. While baleen whales trap their prey in masse, toothed whales capture victims individually. The even, conical teeth found in this group are perfect for catching slippery fish, which form the diet of most species. Sperm whales, however, mostly eat squid (but also other prey, such octopuses), and beaked whales have a mixed diet of fish and squid. Killer whales eat other whales (which they attack in packs), fish, and seals, which they sometimes seize from land, using waves to slide onto the beach. They will also upset sheets of pack ice to knock prey into the water. Fish-eating species (including killer whales) usally have numerous teeth to hold wriggling prey, while those that eat squid or octopuses, for example, have fewer teeth. Sperm whales have functional teeth only in the lower jaw (which is very narrow), and prey is held firmly between these teeth and the roughened palate in the upper jaw. All toothed whales use echolocation to help them find prey (and to help them to avoid objects in their path).  COMMUNICATION AND SENSESBaleen whales communicate using a variety of sounds, from squeals to rumbles. Toothed whales avoid obstacles and catch prey by emmitting high-frequency clicks that are reflected off objects in their path. Cetaceans have extraordiarily sensitive hearing. Vision is reasonable - underwater it is excellent up to about 1 m (3 1/2ft), and in air up to 2.5m ( 8 1/2ft), but colour vision is very limited. Some species can focus both eyes ahead, above, or behind them, and some can move their eyes independently. Some freshwater dolphins, however, are nearly or entirely blind. Members of the toothed whale group produce high frequency clicks for echolocation and can also communicate using a wide range of sounds audible to humans. Other cetaceans employ a variety of vocalizations, but these are less well studied. Cetaceans have no sence of smell. BEHAVIOR The range of behavior in whales reflects their long evolutionary history and diversity of environments. Smaller toothed whales are generally faster than the baleen whales, as they actively hunt their prey, using echolocation. Most baleen whales make seasoal migrations from feeding grounds near the Poles to tropical breeding areas. Some cover a distance almost equal to half the Earth's circumference in a year. Whale migrations are not necessarily a well-defined procession of animals moving north or southward at an exact time of year. Humpback and gray whales do engage in regular migrations; other baleens take the prevailing ecological conditions into consideration. These are some of my favorite whale and dolphin pictures. To view a larger image please click on the thumbnails below.
 "Almost 1,000 whales, dolphins and porpoises die every day in nets and fishing gear. That's one every two minutes,"-WWF Conservation Director Dr Ray Nias. More than 300,000 dolphins, porpoises and whales are killed every year because they are getting tangled up in fishing gear. Nets are one of the greatest global threats facing dolphins, porpoises, and whales. If you would like more information about Whales and Dolphins or how you can help protect them, please visit these links below.  The Whale and Dolphin Conservation Society (WDCS) is the global voice for the protection of whales, dolphins and their environmentThe Environmental Investigation Agency (EIA) is an international campaigning organisation committed to investigating and exposing environmental crime. IFAW is helping to save these magnificent animals from commercial whaling and protect endangered whales for future generations. Whales Revenge Please educate yourself, your friends and family about Whaling by visiting GreenPeace or Sea Shepherd Conservation Society and help stop whaling. Whaling is senseless murder. It has to stop! If whales could scream, whaling might have stopped a long time ago. Free Dolphin Screen Saver if you love dolphins, you'll love this screen saver! I have this screen saver on my computer and I could watch it all day! They move like real dolphins and it's really relaxing. You won't regret downloading it!  Living together in peace and harmony... a Southern Right Whale has company with a pod of dolphins. Wild and free, this is how it should be. Back to Realm of Animals main page Send e-mail to Realm of Animals Please leave your comments in my guestbook before you leave. Sign/View Guestbook All graphics, contents and designs Copyright © Realm of Animals 2006 All Rights reserved. Disclaimer and Copyright Information PLEASE READ This site was made for viewing pleasure and education purposes only. No part of this site may be removed, reproduced, stored, saved, altered or copied in any way or by any means without written permission or unless stated otherwise. All graphics were made especially for this site ONLY and are NOT FREE to use. If your still confused, please refer to the following link about Copyright Laws. What is Copyright? |
