Whales and Dolphins

They belong to an order of mammals called Cetaceans They belong to an order of mammals called Cetaceans There are about 80 different species of cetaceans There are about 80 different species of cetaceans The largest are the whales The largest are the whales The smallest are the dolphins and porpoises The smallest are the dolphins and porpoises Dolphins and porpoises are actually small whales that range from 2-4 m in length Dolphins and porpoises are actually small whales that range from 2-4 m in length

Whales and Dolphins Dolphins and porpoises are extremely intelligent and social animals Dolphins and porpoises are extremely intelligent and social animals Basically the only difference between the 2 is that dolphins have a more elongated snout and swim faster Basically the only difference between the 2 is that dolphins have a more elongated snout and swim faster Dolphins swim so fast because they like to catch up to speeding boats and catch a ride in their bow waves Dolphins swim so fast because they like to catch up to speeding boats and catch a ride in their bow waves

Dolphin and Porpoise

Baleen Whales There are 2 main groups of whales – baleen whales and toothed whales There are 2 main groups of whales – baleen whales and toothed whales Baleen whales are filter feeders that eat plankton, small fish, and krill (a tiny shrimp) Baleen whales are filter feeders that eat plankton, small fish, and krill (a tiny shrimp) Baleen whales include such species of whales as the blue whale, finback, humpback, right, and gray whales Baleen whales include such species of whales as the blue whale, finback, humpback, right, and gray whales

The Blue Whale At 30m long and weighing more than 150,000kg, the blue whale is the biggest animal that has ever lived on Earth At 30m long and weighing more than 150,000kg, the blue whale is the biggest animal that has ever lived on Earth It’s even bigger than the largest dinosaurs that ever lived! It’s even bigger than the largest dinosaurs that ever lived! It is a baleen whale, and is harmless It is a baleen whale, and is harmless

Baleen Whales While they swim, they open their mouths and take in enormous quantities of water While they swim, they open their mouths and 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 mouth, it passes through overlapping plates of fibrous protein called baleen As the water is forced from the whales mouth, it passes through overlapping plates of fibrous protein called baleen These hang from the roof of the whale’s mouth and act as a strainer, trapping the organisms These hang from the roof of the whale’s mouth and act as a strainer, trapping the organisms The water is expelled from the mouth, and the food is swallowed The water is expelled from the mouth, and the food is swallowed

Baleen

Toothed Whales Toothed whales, well…they have teeth Toothed whales, well…they have teeth Member of this group of whales are the sperm whale, killer whale, pilot whale, and the beluga whale Member of this group of whales are the sperm whale, killer whale, pilot whale, and the beluga whale Dolphins and porpoises are also toothed whales Dolphins and porpoises are also toothed whales They have teeth, and they use them to catch prey such as fish, seals, penguins, and squid They have teeth, and they use them to catch prey such as fish, seals, penguins, and squid Toothed whales are active hunters Toothed whales are active hunters

Toothed Whales After catching prey, toothed whales usually swallow it whole After catching prey, toothed whales usually swallow it whole The whale’s stomach has compartments that chew the food The whale’s stomach has compartments that chew the food The sperm whale is one of the largest toothed whales The sperm whale is one of the largest toothed whales It grows to about 15m in length It grows to about 15m in length The smallest (not counting dolphins and porpoises) is the narwhal The smallest (not counting dolphins and porpoises) is the narwhal It grows to about 5m It grows to about 5m

Whale Reproduction Whales breed and reproduce in the sea (obviously) Whales breed and reproduce in the sea (obviously) Fertilization and embryo development are internal (because they are mammals!) Fertilization and embryo development are internal (because they are mammals!) The gestation period of whales is about 11 months, and up to as long as 18 months in larger whales The gestation period of whales is about 11 months, and up to as long as 18 months in larger whales Whales breed once every 3 years, and only give birth to one calf at a time Whales breed once every 3 years, and only give birth to one calf at a time This is why so many whales are endangered! This is why so many whales are endangered!

Whale Reproduction Whales are born tail first Whales are born tail first Mother whales nurse the calves for about 6-10 months Mother whales nurse the calves for about 6-10 months Mothers invest a great deal of care in rearing her baby Mothers invest a great deal of care in rearing her baby Milk of whales is high in fat and protein and ensures quick growth and development Milk of whales is high in fat and protein and ensures quick growth and development Baby blue whales drink the equivalent of 400 glasses of milk a day! Baby blue whales drink the equivalent of 400 glasses of milk a day!

Movements of Whales Whales are swimmers and divers Whales are swimmers and divers Some whales float near the surface when killed Some whales float near the surface when killed The right whales do this, and that’s why they were named “right” whales by whalers The right whales do this, and that’s why they were named “right” whales by whalers Breaching – to leap entirely out of the water and then crashing back down Breaching – to leap entirely out of the water and then crashing back down Why? Why? To dislodge parasites, playful behavior, communication To dislodge parasites, playful behavior, communication

Communication Dolphins and some whales (such as sperm whales) use sound waves to sense objects in their environment and to catch prey Dolphins and some whales (such as sperm whales) use sound waves to sense objects in their environment and to catch prey It is a special kind of biological sonar, and it is called echolocation It is a special kind of biological sonar, and it is called echolocation Sound waves are emitted and they bounce off objects/prey and come back, so the dolphins/whales know the locations Sound waves are emitted and they bounce off objects/prey and come back, so the dolphins/whales know the locations Dolphins communicate with other dolphins by clicking sounds they make with their throats Dolphins communicate with other dolphins by clicking sounds they make with their throats

Beaching There have been recorded cases of groups of whales (both baleen and toothed) swimming into shallow waters and becoming stranded when the tide goes out. This is called beaching There have been recorded cases of groups of whales (both baleen and toothed) swimming into shallow waters and becoming stranded when the tide goes out. This is called beaching Of course, many of them die if they aren’t rescued Of course, many of them die if they aren’t rescued Reasons for this strange behavior remain a mystery Reasons for this strange behavior remain a mystery Some guesses: disease, parasites, infections could cause them to become disoriented near the shoreline Some guesses: disease, parasites, infections could cause them to become disoriented near the shoreline Water pollution – PCB’s, DDT, and toxic dinoflagellates have been found in stranded whale tissues Water pollution – PCB’s, DDT, and toxic dinoflagellates have been found in stranded whale tissues

Whales

Strandings