WHALESWHALES

aquatic mammalsaquatic mammals

Whales and dolphins are Whales and dolphins are cetaceanscetaceans

from the Greek word ‘from the Greek word ‘ketos’ ketos’ or whaleor whale

• They originated as land mammals, They originated as land mammals, but evolved from the land to the sea but evolved from the land to the sea about 50-60 million years ago.about 50-60 million years ago.

• The bones in a whale’s pectoral fin The bones in a whale’s pectoral fin are very similar to the bones in a are very similar to the bones in a human arm showing their common human arm showing their common ancestry.ancestry.

Whales of AustralasiaWhales of Australasia

• There are 35 species of cetacean in There are 35 species of cetacean in New Zealand waters:New Zealand waters:– 8 are baleen whales8 are baleen whales– 27 are toothed whales27 are toothed whales

• New Zealand has 3 species not New Zealand has 3 species not occurring in Australiaoccurring in Australia

• Australia has another 10 species Australia has another 10 species which are not found in New Zealand.which are not found in New Zealand.

Toothed Whales & Baleen Toothed Whales & Baleen WhalesWhales

• Whales are divided into 2 groups according Whales are divided into 2 groups according to the way they obtain their food.to the way they obtain their food.

• Toothed whales have Toothed whales have teethteeth. This group of . This group of cetaceans are called cetaceans are called OdontocetiOdontoceti..

• Baleen whales do not have teeth but Baleen whales do not have teeth but instead have a mesh of bristles called instead have a mesh of bristles called baleenbaleen that is attached to the upper jaw that is attached to the upper jaw and acts as a filter. Baleen, like human and acts as a filter. Baleen, like human hair, is made of keratin. This group of hair, is made of keratin. This group of cetaceans are called cetaceans are called MysticetiMysticeti..

BALEEN WHALESBALEEN WHALES

• Baleen means ‘with moustaches’.Baleen means ‘with moustaches’.

• They have evolved to eat huge quantities They have evolved to eat huge quantities of small organisms called of small organisms called planktonplankton which which are available in some areas e.g. krill in are available in some areas e.g. krill in Antarctic waters.Antarctic waters.

• They generally live longer than toothed They generally live longer than toothed whales, up to 70 – 80 years has been whales, up to 70 – 80 years has been known.known.

• They have two blowholes.They have two blowholes.

Baleen WhalesBaleen Whales

The humpback whale above represents a typical baleen whale.

HowHow they feed -they feed -• Some of them gulp in the water including the Some of them gulp in the water including the

food and squeeze the water out the side of food and squeeze the water out the side of their mouth. These whales are their mouth. These whales are rorquals rorquals and and have pleats under their throats which expand have pleats under their throats which expand to allow them to gulp huge quantities of water. to allow them to gulp huge quantities of water. A Blue Whale can gulp up to 5 tons of water.A Blue Whale can gulp up to 5 tons of water.

• Others such as the Right Whale swim with Others such as the Right Whale swim with their mouths open and swing their head from their mouths open and swing their head from side to side using the baleen to filter out the side to side using the baleen to filter out the plankton.plankton.

• Now try the investigation to show how baleen Now try the investigation to show how baleen filters food.filters food.

TOOTHED WHALESTOOTHED WHALES

• They have one blowhole.They have one blowhole.

• Most female toothed whales are Most female toothed whales are smaller than males while in baleen smaller than males while in baleen whales females are generally larger whales females are generally larger than the males.than the males.

• In the next diagram, a bottlenose In the next diagram, a bottlenose dolphin is used to represent toothed dolphin is used to represent toothed whales. whales.

Toothed WhalesToothed Whales

HowHow they feed -they feed -• Toothed whales eat fish and squid by Toothed whales eat fish and squid by

grasping them in their teeth. grasping them in their teeth. • They do not chew their food, but use They do not chew their food, but use

their tongue to turn the fish so that it their tongue to turn the fish so that it goes down head first.goes down head first.

• The Killer Whale is the only true eater The Killer Whale is the only true eater of warm-blooded prey. They have been of warm-blooded prey. They have been known to eat seals and other known to eat seals and other cetaceans.cetaceans.

• Watch the video of Orca hunting.Watch the video of Orca hunting.

Whales are not fish! They are Whales are not fish! They are mammalsmammals• They are warm-blooded & give birth to live They are warm-blooded & give birth to live

babies (tail first) and feed them with milk rich babies (tail first) and feed them with milk rich in nutrients.in nutrients.

• The gestation period varies according to the The gestation period varies according to the species but may be between 9 to 18 months.species but may be between 9 to 18 months.

• Baby whales don’t suck, instead the milk is Baby whales don’t suck, instead the milk is squirted out of the teats down the baby’s squirted out of the teats down the baby’s throat.throat.

• Whale tail flukes are horizontal structures; Whale tail flukes are horizontal structures; their tails move up and down, instead of side their tails move up and down, instead of side to side as fish tails do.to side as fish tails do.

Mammal breathing …. not fish Mammal breathing …. not fish breathingbreathing

• Whales must surface in order Whales must surface in order to breathe, unlike fish. This to breathe, unlike fish. This can be spotted by an observer can be spotted by an observer by the ‘blow’ or ‘spout’ from by the ‘blow’ or ‘spout’ from the whale’s blowhole. Click the whale’s blowhole. Click here to watch a sperm whale here to watch a sperm whale ‘blowing’. ‘blowing’.

• Blowholes are like nostrils on Blowholes are like nostrils on top of their heads and the top of their heads and the ‘blow’ is actually condensing ‘blow’ is actually condensing water vapour.water vapour.

• Whales are able to stay under Whales are able to stay under water because their lungs fill water because their lungs fill to their capacity and they to their capacity and they change up to 90% of this each change up to 90% of this each time they breathe.time they breathe.

Whale2.mpg

How do whales keep warm?How do whales keep warm?

• They store some of their food as an insulating They store some of their food as an insulating layer of layer of blubberblubber just under the skin’s surface.just under the skin’s surface.

• The blubber reduces heat loss to the The blubber reduces heat loss to the surrounding water and also acts as an energy surrounding water and also acts as an energy reserve for long migrations.reserve for long migrations.

• Now try the experiment to demonstrate how Now try the experiment to demonstrate how blubber is effective in reducing heat loss.blubber is effective in reducing heat loss.

Sleeping and SwimmingSleeping and Swimming

• Whales have very streamlined bodies to help Whales have very streamlined bodies to help them move easily through the water.them move easily through the water.

• Cetaceans are among the fastest swimmers in Cetaceans are among the fastest swimmers in the sea. They are powered by their tail flukes the sea. They are powered by their tail flukes moving up and down.moving up and down.

• Their flippers are for balance and steering.Their flippers are for balance and steering.• Whales sleep with their blowhole just at the water Whales sleep with their blowhole just at the water

surface. They control their breathing even when surface. They control their breathing even when asleep.asleep.

• If they lose consciousness the blowhole closes to If they lose consciousness the blowhole closes to avoid drowning.avoid drowning.

• Whales tend to take short naps. Whales tend to take short naps.

Being SocialBeing Social• Cetaceans generally live in groups called Cetaceans generally live in groups called

pods pods which vary greatly in size according which vary greatly in size according to the species.to the species.

• Some group into nursery groups at Some group into nursery groups at breeding times with the males remaining breeding times with the males remaining apart at other times.apart at other times.

• Another whale is often involved during the Another whale is often involved during the birth of a calf and helps nudge the calf to birth of a calf and helps nudge the calf to the surface to take its first breaths.the surface to take its first breaths.

• It may be that some social behaviour is It may be that some social behaviour is responsible for whales not leaving other responsible for whales not leaving other stranded whales after they themselves stranded whales after they themselves have been rescued.have been rescued.

SensingSensing

• The sense of sight is not the predominant The sense of sight is not the predominant one for whales given the murkiness of one for whales given the murkiness of their environment.their environment.

• The sense of touch is present & The sense of touch is present & demonstrated by whales rubbing against demonstrated by whales rubbing against each other.each other.

• Toothed whales do not have a sense of Toothed whales do not have a sense of smell, and it is limited in baleen whales.smell, and it is limited in baleen whales.

• Toothed whales use Toothed whales use echolocationecholocation to sense to sense things around them. Baleen whales may things around them. Baleen whales may use it but less is known about this.use it but less is known about this.

EcholocationEcholocation• The whales make a clicking sound which The whales make a clicking sound which

produces vibrations that travel through the produces vibrations that travel through the water.water.

• The sound waves are bounced off any The sound waves are bounced off any solid objects, and the whale is able to work solid objects, and the whale is able to work out the direction and distance of the out the direction and distance of the object, and even its shape, e.g. whether it object, and even its shape, e.g. whether it is another animal or the sea floor.is another animal or the sea floor.

• Watch the video of echolocation helping to Watch the video of echolocation helping to hunt a giant squid.hunt a giant squid.

CommunicatingCommunicating• Toothed whales communicate by making Toothed whales communicate by making

whistling sounds which appear to transmit whistling sounds which appear to transmit complex and intentional messages.complex and intentional messages.

• Baleen whales produce a variety of sounds Baleen whales produce a variety of sounds including whistles, clicks, thumps and moans.including whistles, clicks, thumps and moans.

• Humpbacks are known for their ‘singing’ –Humpbacks are known for their ‘singing’ –some songs can last up to 30 minutes and some songs can last up to 30 minutes and are thought to be the longest and most are thought to be the longest and most complex of any animal. These are really ‘love complex of any animal. These are really ‘love songs’ and occur during the breeding season.songs’ and occur during the breeding season.

• A Blue Whale’s whistle is the loudest sound A Blue Whale’s whistle is the loudest sound known to be produced by anything living.known to be produced by anything living.

• Watch the video about research that was Watch the video about research that was carried out on how and what whales hear.carried out on how and what whales hear.

MigrationMigration

• Many whales migrate between feeding and Many whales migrate between feeding and breeding grounds, e.g.breeding grounds, e.g.– Humpbacks migrate north to around Samoa, Humpbacks migrate north to around Samoa,

Tonga and New Caledonia to breed in autumn Tonga and New Caledonia to breed in autumn and south to the Antarctic to feed in spring.and south to the Antarctic to feed in spring.

• The whales migrate in 3 phases:The whales migrate in 3 phases:– The pregnant females leave first in order to get The pregnant females leave first in order to get

to the new feeding grounds first and so get the to the new feeding grounds first and so get the most food.most food.

– The males migrate next.The males migrate next.– Finally, the non-pregnant females and those Finally, the non-pregnant females and those

with calves.with calves.

Tracking & the effects of Tracking & the effects of humans on whaleshumans on whales

• Marine scientists have been tracking Marine scientists have been tracking the migratory patterns of whales in the migratory patterns of whales in order to study how whales are affected order to study how whales are affected by changes in the environment. by changes in the environment.

• For example, scientists have found that For example, scientists have found that toxic pollutants in the water suppress toxic pollutants in the water suppress whales’ immune systems, causing whales’ immune systems, causing many to grow sick and die. many to grow sick and die.