FAMILY NATURE NOTES WINTER 2003 Written by Kerry Everitt Design and illustrations by Judie Shore Did you know that the largest species of mammal in the world is found just off the coast of Canada? humpback Whales mother and Giants of the Ocean calf Way up north, in the Canadian Arctic, you can see narwhals and bow- head whales. Hundreds of beluga whales live quite close to us here in Ontario in the St. Lawrence River and farther north in Hudson Bay. Humpback whales, minke whales, fin whales and the gigantic blue whale can be found along both the Pacific and Atlantic coasts. Although they live entirely in the water, whales, dolphins and porpoises are actually mammals. These sorts of mammals are called cetaceans. Unlike insects, which have millions of different species, there are only about 80 species of cetaceans worldwide. Whales of all shapes and sizes are found in every ocean from the warm tropics to the icy poles. Millions of years ago, when mammals first evolved, they lived on land. How and why ancestors of the whales moved from their terrestrial habitat into the seas and oceans is unknown. About 55 million years ago, a group of mammals moved into the shallow marine environment. Gradually these creatures evolved and adapted to their new watery habitat and became the whales we know today. Their nostrils moved to the top of their heads (now called blowholes), and they developed strong tails for swimming. Their front legs transformed into flippers, and their hind legs completely disappeared. In some whales you can still find leg bones called vestigial bones, remnants of the time when these creatures were land mammals and walked on four legs. Protocetus was a primitive cetacean that lived 50 million years ago. (2.5m) Whale Fish are covered Fish have adapted to life in Because whales are mammals, or Cetacean? with thousands the water by having gills to they must breathe oxygen Even though whales live in the water, of tiny scales. help them breathe. directly from the air. To do they are not fish. They are warm-blood- this, they use blowholes on ed, give birth to live young and top of their heads, which let breathe oxygen just like you. them breathe once they reach shark the surface of the water. The easiest way to tell a whale from a fish is to look at its tail. A fish tail is vertical and moves side-to-side. A whale's tail fins, called flukes, are whale horizontal and move up and down. A whale's skin is smooth. Visit us on the Web at www.ontarionature.org FAMILY NATURE NOTES WINTER 2003 Written by Kerry Everitt Save the Design and illustrations by Judie Shore humpback A Whale Whales whale breaching of a Word "Thar She Blows!" was a phrase once Did you know that the largest species of commonly heard on our oceans. When a whale mammal in the world is found just off the surfaces and exhales, a large spout of water Search vapour can easily be seen, alerting hunters Find the hidden whale words; they could be horizon- coast of Canada? of the location of their prey. Long ago, tal, vertical or diagonal. Write out the remaining let- men hunted whales from small boats using ters to spell a phrase about whales. hand-thrown spears, a method that allowed the whale a good chance of getting away. After the NYROS F ENUGC ENGAL industrial revolution, boats became larger, faster NIHELLENNOCEANEA and stronger, and exploding harpoons replaced spears. Whales DL FUBEAI DNWSEOP I had little chance against these weapons and, as a result, many species were ETKMLBHMEALHCSOG hunted to near extinction. Although a worldwide ban to put an end to com- HESA I CURMENNAAV I mercial whaling was agreed upon in 1986, there are still some countries that TEBTAGWLBAOGTLAT defy the international whaling ban and continue to kill these majestic mam- OH E EWAR I BIMHERES mals. Scientists question whether whale populations will ever fully recover. ORRAL L CATPODCRSE Whales are also vulnerable to habitat destruction, accidental cap- TBCTEESATTHTEKEV ture in fishing nets, marine pollution and being hit by ships. GESADNCT L I I EG RI D Toxic chemicals enter our oceans every day. Untreated ELOHWOLBACONF ISH humpback Whales mother and sewage, industrial waste, agricultural chemicals and oil T A G U L E B N O TKNALPT calf spills all threaten the health of our oceans and the ASNO I TUL LOPOFLTH Giants of the Ocean lives of the whales that live in them. I E H E L B A RENLUVOCE ay up north, in the Canadian Arctic, you can see narwhals and bow- head whales. Hundreds LCSQUI DDORSALANS W bowhead of beluga whales live quite close to us here in Ontario in the St. Lawrence River and farther north in EN I RAMAC I TCRATNA whale Hudson Bay. Humpback whales, minke whales, fin whales and the gigantic blue whale can be found along both the Pacific and Atlantic coasts. ANTARCTICA ENDANGERED POD Although they live entirely in the water, whales, dolphins and porpoises are actually mammals. ARCTIC FIN POLLUTION These sorts of mammals are called cetaceans. Unlike insects, which have millions of different species, there BALEEN FISH SEA are only about 80 species of cetaceans worldwide. Whales of all shapes and sizes are found in every ocean BELUGA FLUKE SONG from the warm tropics to the icy poles. When you or your parents are cleaning up BLOWHOLE KRILL SQUID Millions of years ago, when mammals first evolved, they lived on land. How and why ancestors of the paint, oil or chemicals, be sure to follow proper disposal BLUBBER MAMMALS STLAWRENCE Supplement to SEASONS, 2003 Winter whales moved from their terrestrial habitat into the seas and oceans is unknown. About 55 million years ago, guidelines so that these toxic substances won't make their way BREACHING MARINE TAIL a group of mammals moved into the shallow marine environment. Gradually these creatures evolved and adapted to their new watery habitat and became the whales we know today. Their nostrils moved to the top of into our waterways. CETACEAN MIGRATION TOOTHED their heads (now called blowholes), and they developed strong tails for swimming. Their front legs transformed If whales become entangled in drift nets meant to capture fish, they will DECIBEL OCEAN VESTIGIAL into flippers, and their hind legs completely disappeared. In some whales you can still find leg bones drown. Remember, whales are mammals and need to breathe oxygen. DORSAL ORCA VULNERABLE called vestigial bones, remnants of the time when these creatures were land mammals Hundreds of thousands of cetaceans are caught in fishing nets each year or ECHOLOCATION PLANKTON WHALE become entangled in the rope that is attached to the fishing gear. Because and walked on four legs. very few are able to break free, nearly all that are caught drown. If you eat _ _ _ _ _ _ _ _ _ _ _ _ Protocetus was a primitive cetacean that lived 50 million years ago. (2.5m) tuna, be sure to buy dolphin-friendly brands, meaning the tuna is caught in a method that does not kill dolphins. _ _ _ _ _ _ _ _ _ _ _ _ _ Whale Fish are covered Fish have adapted to life in Because whales are mammals, or Cetacean? with thousands the water by having gills to they must breathe oxygen Some large whales do break free from fishing gear, only to die from bacte- Even though whales live in the water, rial infections or have the rope tightly wrapped around their mouths so they _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ of tiny scales. help them breathe. directly from the air. To do they are not fish. They are warm-blood- this, they use blowholes on cannot feed and slowly starve. Teams of people try to disentangle these _ _ _ _ _ _ _ _ _ _ _ ed, give birth to live young and top of their heads, which let whales, but it is very difficult work and can be very dangerous. The whales breathe oxygen just like you. them breathe once they reach shark may still die afterwards from infections. Fishermen and scientists often work oceans. the of the surface of the water. ou can help to save the whales the gentle giants gentle the whales the save to help can ou Y together to try to solve this difficult problem. Answer: The easiest way to tell a whale from a fish is to look at its tail. A fish tail is vertical and moves side-to-side. Reviewer: Sarah Ingwersen, Adopt-A-Pond Coordinator This paper comes from well-managed forests, inde- whale Copy Editor: Joan Clark, Editor: Helen D. Gault A whale's tail fins, called flukes, are pendently certified in accordance with the rules of Printing: MPH Graphics Inc. horizontal and move up and down. A whale's skin is smooth. the Forest Stewardship Council A.C. Certified by 355 Lesmill Rd, Don Mills, ON M3B 2W8 Tel: (416) 444-8419, Smartwood SW-C0C-319. FSC Trademark© 1996 1 800 440-2366 Fax: (416) 444-9866 E-mail: [email protected] Forest Stewardship Council A.C. t Whales in Canada Many whales spend a portion of the year in Canadian waters. If you go out on a whale-watching northern right whale expedition on the east coast, west coast or to the Arctic, you may be lucky enough to see beluga, bowhead, gray, minke, sei, blue, fin, hump- The Life of a Whale Much like their mammal cousin the bat, many whales (mainly back, northern right, narwhal, pilot or orca whales.