1. Whales

2. Fossil Record
Shows that some land animals began to make the transition to sea animals about 50 million years ago.

3. Mammals Whales are mammals and all mammals share 3 characteristics:
Hair
Feed young with milk from mammary glands
Have a 4-chambered heart

4. belong to the Order Cetacea
Whales and Dolphins
belong to the Order Cetacea
There are about 80 species

5. Whales versus Dolphins
Whales are largest and dolphins and porpoises are the smallest.

6. Baleen Whales Two blowholes Baleen plates – filter feeders
Plates grow to several feet in length
May be several hundred in one animal
Flat on outer edge, bristles on inner edge trap small organisms
Krill: food source for many baleen whales
Includes the humpback, blue, finback, right, sei, and gray whales.

8. Baleen

9. Toothed Whales One blowhole Have teeth to seize prey
Include the Sperm, killer, pilot, beluga, dolphins and porpoises
Killer whales: top carnivores

10. Baleen Whale vs. Toothed Whale Size

11. Whale Reproduction Fertilization and development are internal
Whales breed about every 3 years and the female whale, or “cow”, stays pregnant between 11 and 18 months.
Whales are born tail first.
Nurse for 6-10 months
A blue whale calf drinks the equivalent of 400 glasses of milk per day and the milk is 50% fat in content.

12. Whale Birth

13. Adaptations and Behaviors
Whales breathe through their blowholes which are connected to their lungs, not their stomachs (Dory and Marlin would never have been shot out the blowhole).
Blowhole is on the dorsal side of their bodies, up on their head, so it surfaces first
Baleen whales have 2 blowholes, toothed whales have 1 blowhole

14. Blowhole

15. Swimming
Whales swim by the up and down movement of their hind flippers or tail flukes
The dorsal fin helps keep them on course
Pectoral fins are used for steering, braking and balance.
The bones inside the fin are similar to the bone structure of the hands of land mammals and whales still have hip bones.

16. Whale Skeleton

17. Diving
Whale uses its pectoral fins to change from horizontal to vertical.
The tail flukes then push the body down into the water head-first

18. Lunging – swim up to the surface and engulf food
(bubble net)

19. Lobtailing Waves tail in the air then smashes it into the water.
Not fully understood by scientists
May be a sign of aggression or a way to announce its presence.

20. Spyhopping
Whale raises head above the water’s surface to look around for a few seconds.
May be a sign of curiosity

21. Breaching – leaps almost completely out of the water and crashes back down with a huge splash.

22. Whale Migration
Whales spend the summers feeding in the waters off the Bering Sea and Arctic Ocean. These waters are nutrient rich and contain a lot of plankton.
During the winter, whales migrate to warmer, shallow waters around Baja California (Gray Whale) or Mexico (Humpback) to breed and have their young.

23. Migration Map

24. Keeping Warm
Blubber keeps whales warm (they are endothermic or warm blooded) in water.

25. Echolocation- form of sonar where the whale bounces sound off of objects to detect objects in the water

26. Stranding
Stranding is where a dolphin or whale swims into shallow waters and becomes beached.
The whales die as their internal organs are crushed by their own body weight.
It is puzzling because, for whatever reason, their echolocation system is not working.
May be caused by PCBs and DDT or natural toxins in the water.

27. Mass Stranding
Pilot Whales are the most commonly stranded whale. May have been caused by the use of sonar by navy ships.

28. Threats to Cetaceans 1. Hunting – both regulated and unregulated
2. Pollution – PCBs and DDT may interfere with echolocation causing strandings
Oil slicks also a big problem
3. Overfishing or killing of whales’ food source(s).
4. Noise – interfering with echolocation
5. Unintentional tangling in nets used for other purposes (dolphins in tuna nets)

29. Blue

30. Humpback

31. Right

32. Minke

33. Gray

34. Toothed Whales

35. Spyhopping
Narwhal

36. Sperm

37. Beluga

38. Humpbacks are identified by the
markings and shape of their tails
(Also an example of lobtailing)