Order - Sirenia (Sirenians)

Manatees, dugong, sea cows, and mermaids - • Front flippers/ no rear• Swim with up and

down tail motion

• Wrinkled skin with little hair

• Padded with blubber• Only strict vegetarian

of marine mammalsStellar Sea Cow- (10 tons)

were extinct 1768- reproduce slowly- 1 calf every 3 years

• Marine mammal act of 1972- protects sale of marine mammal products

Kingdom- Animalia Phylum- Chordota Class- Mammalia

Order- Cetacea

The Cetaceans (whales, dolphins, and porpoises):

• Of all marine mammals- Whales made the most complete transition to aquatic life (entire life in water)

• They include the largest animal that has ever lived, the blue whale,

the highly intelligent and communicative dolphins;

the tusked narwhals and blind river dolphins

and singing humpback whales-nearly 80 living species in all.

• Body- fish like- (convergent evolution) similar life style

• Not fish like- breathe air, endotherms have hair and produce milk

• Elongated skull allows nostrils on top-Blowhole

• Forelimbs are specialized to form flippers

• Rear flippers- present in embryo stage, but not in adult stage. Hind limbs and pelvis are extremely small do not normally extend out of the body wall.

Fetus of a white sided dolphin

• Dorsal fin in many

•Tail with two finlike flukes arranged horizontally.

Cetaceans are divided into 2 groups:Toothless- baleen whales - Mysticeti Ex. Humpback and Blue whalesToothed- Carnivorous whales - Odontoceti Ex. Orca, Sperm Whales, Dolphins, and Porpoises

Baleen Whales

Toothed Whales

Baleen Whales• Baleen whales, instead of teeth have rows of

flexible, fibrous plates that hang from the upper jaw. Made of material like hair and nails. The whale feeds by taking big gulp of H2O and squeezing out through baleen, licks food off inside.

Some Baleen whales have ventral pleats to increase size of mouth

Some like humpbacks, are known for complex songs but do not use singing for echolocationBaleens- have 2 blowholesBaleen whales are the largest animal on earth

Rorquals

Rorquals- Baleen whales with ventral pleats like the Blue, Fin, Minke, Sei and Humpback Whales

Minke Whale

Toothed Whales

Toothed whales- dolphins, porpoises, sperm whales, killer whale (Orca)

Odontocetes ( toothed whales)• Bear teeth typically numerous peg like teeth,

sometimes modified like the single tusk of the Narwhal.

Male Narwhals have two teeth, the left one becomes the tusk that protrudes through the upper jaw.

Odontocetes ( toothed whales)

• Sperm whales- accumulate undigested squid beaks and debris called ambergris (used in fine perfume)

• Dolphins- have distinctive beak or snout and travel in pods

Whales are long-lived, slow reproducing- which is why whaling is threatening their populations.

Whale - spout or blow- exhale through blowhole.

spout or blow

spout or blow

Breach

Breach

Right Whale

Breach

OrcaHumpback

Whale Behavior

spying

carrying companion

injured member of pod

Beluga