1. Marine mammals Characteristics of marine mammals: Warm-blooded
Breathe air
Have hair (or fur)
Bear live young
Females have mammary glands that produce milk for their young

2. Marine mammals: Order Carnivora
All members of order Carnivora have prominent canine teeth
Includes:
Sea otters
Polar bears
Pinnipeds (flipper-footed)
Walrus
Seals
Sea lions/fur seals
California sea lions
Figure 14-17c

3. Differences between seals and sea lions/fur seals
Lack ear flaps
Have small front flippers
Have claws
Cannot rotate hind flippers beneath themselves
Figure 14-18

4. Whales, dolphins and porpoises are cetaceans (Class Mammalia, Order Cetacea)
Of all the marine mammals, cetaceans (and sirenians) have made the most complete transition to aquatic life
Spend their entire lives in the water
The bodies of cetaceans are streamlined and look remarkably fish-like; an example of convergent evolution

5. Convergent Evolution: Streamlining
Convergent evolution is the process by which unrelated species evolve similar physical characteristics because they have similar lifestyles

6. Whales, Dolphins, and Porpoises
Cetaceans have a pair of front flippers, but the rear pair of limbs has virtually disappeared
Remain in adults as small, useless bones
Most cetaceans have a dorsal fin, like fishes
Their muscular tail ends in a pair of fin-like, horizontal flukes

7. Whales, Dolphins, and Porpoises
Blubber provides cetaceans with insulation
Cetacean nostrils are on top of the head, forming a single, or double opening called the blowhole

8. There are ~90 species of cetaceans
All are marine, except for 5 species of freshwater dolphins
Cetaceans are divided into two groups:
Toothed whales – includes dolphins & porpoises
Baleen whales; toothless, filter-feeding whales
Photos property of the Riverhead Foundation

9. Marine mammals: Order Cetacea
Cetacean characteristics:
Blowholes on top of skull
Skull telescoped (streamlined shape)
Very few hairs
Includes:
Whales, dolphins, and porpoises

10. Marine mammals: Order Cetacea
Figure 14-20

11. Two suborders of order Cetacea
Suborder Odontoceti (toothed whales)
Echolocate (send sound through water)
Includes killer whale, sperm whale, dolphins, porpoises, and many others
Suborder Mysticeti (baleen whales)
Have rows of baleen plates instead of teeth
Includes blue whale, finback whale, humpback whale, gray whale, and many others

13. Types of baleen whales Baleen whales include three families:
Gray whale (a bottom-feeder with short baleen)
Rorqual whales (medium-sized baleen)
Balaenopterids (blue whales, finback whales, and other large whales )
Megapterids (humpback whales)
Right whales (surface skimmers with long baleen)

14. Mysticeti: The baleen whales
Mysticeti whales have baleen instead of teeth
Baleen plates:
Hang as parallel rows from the upper jaw
Are made of keratin
Are used as a strainer to capture zooplankton
Allows baleen whales to eat krill and small fish by the ton

15. Baleen
Figure 14-25

17. Baleen Whales

18. Baleen whales are characterized not only by their baleen, but by the double opening of their blowholes (double blowhole)
Baleen whales can be further divided into the rorquals; rorquals feed by gulping up schools of fish and swarms of krill
The lower portion of the throat expands during feeding, along distinctive grooves

19. BALEEN

21. The majority of cetaceans are toothed whales
Toothed whales use their teeth only to catch and hold prey, not to chew it
Toothed whales have a single blowhole (one opening) on the top of their head
Though they are all whales, most of the small toothed whales are called dolphins or porpoises

22. The Toothed Whale Whales
The toothed “whales” include the sperm whale, beluga, pilot whales, beaked whales, and orca, each divided into their own families

23. Differences between dolphins and porpoises
Dolphins have:
An elongated snout (rostrum)
A sickle-shaped (falcate) dorsal fin
Teeth that end in points
Killer whale jawbone
Figure 14-22

24. Generation of Odontoceti echolocation clicks
Figure 14-23

25. Echolocation

26. Odontoceti echolocation
Sound is bounced off objects to determine:
Size
Shape
Distance
Internal structure
Figure 14-24

27. Marine mammals: Order Sirenia
Sirenian characteristics:
Large body size
Sparse hair all over body
Vegetarians
Toenails (on manatees only)
Includes:
Manatees
Dugongs

29. An example of migration: Gray whales
Gray whales undertake the longest annual migration of any mammal:
Spend wintertime in birthing and breeding lagoons in Mexico
Spend summertime feeding in highly productive Arctic waters
Figure 14-27