gray whales
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Gray Whales
By Connor Muilenburg
Gray Whale Topics
• Physical description• Whales are mammals• Feeding• Swimming behaviors• Migration • Breeding• Predators• Population
Physical Description
• Gray whales grow to be 45-50 feet long. • Gray whales weigh about 36 tons. • The gray whale's skin is gray with white
spots and has lots of barnacles.• The gray whale has two flippers, no dorsal
fin, and small ridges along its back. • Gray whales have baleens (not teeth) and
two blow holes.
Gray Whale Diagram
Whales are Mammals
Gray whales are mammals because:
• They have hair (calves have hair on the front of their head).
• They give birth to live young.
• They have lungs to breathe air.
• They are warm blooded.
• Whale calves drink their mother’s milk.
• Gray whales are the only bottom feeding whale. • They eat shrimp-like amphipods, crustaceans, worms, fish
and squid that live in the muddy bottoms of the North Pacific Ocean.
• They scoop up a mouthful of mud, the baleens filter out the food, then the whale spits out the mud.
• The whale will stay down for 3-5 minutes to eat. • A trail of dents in the ocean floor is left behind where the
whale hit the ground.• A single gray whale is believed to turn over 50 acres of
sediment during a season of feeding.
Feeding
Swimming Behaviors
Breeching is when a whale jumps out of the water and then splashes down.
Sounding is when a whale shows its flukes.
More Swimming Behaviors
Spouting is when a whale blows out air and water drops spray up.
Spy-hopping is when a whale comes out of the water high enough to see.
• Gray whales spend the summer and part of the fall in the Chukchi Sea to feed in the rich Arctic waters.
• Gray whales spend the winter in the warm waters near Baja, CA to calve and mate.
• The round-trip is a 12,500 mile swim.
Migration
• Gray whales breed mostly in warm waters.
• The gestation period is about 13.5 months.
• The newborn calf is about 15 feet long and weighs about one ton.
• Within 30 minutes of birth the baby whale can swim.
• Calves drink milk for 6 to 7 months.
• The mother and calf stay together for about a year.
• Females have a calf every 2 or more years.
Breeding
• Killer whales, large sharks, and humans are the gray whales' only natural predators.
• Killer whales hunt gray whales off the Pacific Northwest coast of the USA.
• There has been an increase in the number of packs of killer whales waiting for the mothers and calves to begin their northward journey.
• Rogue or wild Orcas follow the gray whales along the migration route.
Predators
• The gray whale population went way down after 1857 because a hunter found the Baja, CA calving grounds. Whales were easy to kill in the shallow water.
• In 1925 factory boats were invented which made whaling easier.
• By 1946 gray whales were almost hunted to extinction.
Population
• In 1946 laws were made so no more whaling was allowed. The gray whale population is now over 20,000 worldwide.
American Cetacean Society (1996). American Cetacean Society Fact Sheet: Gray Whales. Online: http://www.acsonline.org/factpack/graywhl.htm
Baja Jones Adventure Travel (2001). The Gray Whale Advocate. Online: http://www.greywhale.com
Enchantedlearning.com (2001). All About Whales. Online: http://www.enchantedlearning.com/subjects/whales/species/Graywhale.shtml
No Author Listed (1998). California Gray Whale Tutorial. Online: http://www.slocs.k12.ca.us/whale/whale1.html
References
The End
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