Whales and DolphinsWhales and Dolphins

Whales and DolphinsWhales and Dolphins• They belong to an order of mammals called They belong to an order of mammals called

CetaceansCetaceans• There are about 80 different species of There are about 80 different species of

cetaceanscetaceans• The largest are the whalesThe largest are the whales• The smallest are the dolphins and porpoisesThe smallest are the dolphins and porpoises• Dolphins and porpoises are actually small Dolphins and porpoises are actually small

whales that range from 2-4 m in lengthwhales that range from 2-4 m in length

Whales and DolphinsWhales and Dolphins• Dolphins and porpoises are extremely Dolphins and porpoises are extremely

intelligent and social animalsintelligent and social animals• Basically the only difference between Basically the only difference between

the 2 is that dolphins have a more the 2 is that dolphins have a more elongated snout and swim fasterelongated snout and swim faster

• Dolphins swim so fast because they Dolphins swim so fast because they like to catch up to speeding boats and like to catch up to speeding boats and catch a ride in their bow wavescatch a ride in their bow waves

Dolphin and PorpoiseDolphin and Porpoise

Baleen WhalesBaleen Whales• There are 2 main groups of whales – There are 2 main groups of whales –

baleen whales and toothed whalesbaleen whales and toothed whales• Baleen whales are filter feeders that Baleen whales are filter feeders that

eat plankton, small fish, and krill (a eat plankton, small fish, and krill (a tiny shrimp)tiny shrimp)

• Baleen whales include such species Baleen whales include such species of whales as the blue whale, finback, of whales as the blue whale, finback, humpback, right, and gray whaleshumpback, right, and gray whales

The Blue WhaleThe Blue Whale• At 30m long and weighing more than At 30m long and weighing more than

150,000kg, the blue whale is the 150,000kg, the blue whale is the biggest animal that has ever lived on biggest animal that has ever lived on EarthEarth

• It’s even bigger than the largest It’s even bigger than the largest dinosaurs that ever lived!dinosaurs that ever lived!

• It is a baleen whale, and is harmlessIt is a baleen whale, and is harmless

Baleen WhalesBaleen Whales• While they swim, they open their mouths While they swim, they open their mouths

and take in enormous quantities of waterand take in enormous quantities of water• This water contains plankton, small fish, etc.This water contains plankton, small fish, etc.• As the water is forced from the whales As the water is forced from the whales

mouth, it passes through overlapping plates mouth, it passes through overlapping plates of fibrous protein called baleenof fibrous protein called baleen

• These hang from the roof of the whale’s These hang from the roof of the whale’s mouth and act as a strainer, trapping the mouth and act as a strainer, trapping the organisms organisms

• The water is expelled from the mouth, and The water is expelled from the mouth, and the food is swallowedthe food is swallowed

BaleenBaleen

Toothed WhalesToothed Whales• Toothed whales, well…they have teethToothed whales, well…they have teeth• Member of this group of whales are the Member of this group of whales are the

sperm whale, killer whale, pilot whale, and sperm whale, killer whale, pilot whale, and the beluga whalethe beluga whale

• Dolphins and porpoises are also toothed Dolphins and porpoises are also toothed whaleswhales

• They have teeth, and they use them to catch They have teeth, and they use them to catch prey such as fish, seals, penguins, and squidprey such as fish, seals, penguins, and squid

• Toothed whales are active huntersToothed whales are active hunters

Toothed WhalesToothed Whales• After catching prey, toothed whales After catching prey, toothed whales

usually swallow it wholeusually swallow it whole• The whale’s stomach has compartments The whale’s stomach has compartments

that chew the foodthat chew the food• The sperm whale is one of the largest The sperm whale is one of the largest

toothed whalestoothed whales• It grows to about 15m in lengthIt grows to about 15m in length• The smallest (not counting dolphins and The smallest (not counting dolphins and

porpoises) is the narwhalporpoises) is the narwhal• It grows to about 5mIt grows to about 5m

Whale ReproductionWhale Reproduction• Whales breed and reproduce in the sea Whales breed and reproduce in the sea

(obviously)(obviously)• Fertilization and embryo development are Fertilization and embryo development are

internal (because they are mammals!)internal (because they are mammals!)• The gestation period of whales is about 11 The gestation period of whales is about 11

months, and up to as long as 18 months in months, and up to as long as 18 months in larger whaleslarger whales

• Whales breed once every 3 years, and only Whales breed once every 3 years, and only give birth to one calf at a timegive birth to one calf at a time

• This is why so many whales are This is why so many whales are endangered!endangered!

Whale ReproductionWhale Reproduction• Whales are born tail firstWhales are born tail first• Mother whales nurse the calves for about 6-Mother whales nurse the calves for about 6-

10 months10 months• Mothers invest a great deal of care in Mothers invest a great deal of care in

rearing her babyrearing her baby• Milk of whales is high in fat and protein and Milk of whales is high in fat and protein and

ensures quick growth and developmentensures quick growth and development• Baby blue whales drink the equivalent of Baby blue whales drink the equivalent of

400 glasses of milk a day!400 glasses of milk a day!

Movements of WhalesMovements of Whales• Whales are swimmers and diversWhales are swimmers and divers• Some whales float near the surface when Some whales float near the surface when

killedkilled• The right whales do this, and that’s why they The right whales do this, and that’s why they

were named “right” whales by whalerswere named “right” whales by whalers• Breaching – to leap entirely out of the water Breaching – to leap entirely out of the water

and then crashing back downand then crashing back down• Why? Why? • To dislodge parasites, playful behavior, To dislodge parasites, playful behavior,

communicationcommunication

CommunicationCommunication• Dolphins and some whales (such as sperm Dolphins and some whales (such as sperm

whales) use sound waves to sense objects whales) use sound waves to sense objects in their environment and to catch preyin their environment and to catch prey

• It is a special kind of biological sonar, and It is a special kind of biological sonar, and it is called it is called echolocationecholocation

• Sound waves are emitted and they bounce Sound waves are emitted and they bounce off objects/prey and come back, so the off objects/prey and come back, so the dolphins/whales know the locationsdolphins/whales know the locations

• Dolphins communicate with other dolphins Dolphins communicate with other dolphins by clicking sounds they make with their by clicking sounds they make with their throatsthroats

BeachingBeaching• There have been recorded cases of groups of whales There have been recorded cases of groups of whales

(both baleen and toothed) swimming into shallow (both baleen and toothed) swimming into shallow waters and becoming stranded when the tide goes out. waters and becoming stranded when the tide goes out. This is called This is called beachingbeaching

• Of course, many of them die if they aren’t rescuedOf course, many of them die if they aren’t rescued• Reasons for this strange behavior remain a mysteryReasons for this strange behavior remain a mystery• Some guesses: disease, parasites, infections could Some guesses: disease, parasites, infections could

cause them to become disoriented near the shorelinecause them to become disoriented near the shoreline• Water pollution – PCB’s, DDT, and toxic dinoflagellates Water pollution – PCB’s, DDT, and toxic dinoflagellates

have been found in stranded whale tissueshave been found in stranded whale tissues

WhalesWhales

StrandingsStrandings