Marine Mammals..

Marine Mammals• Warm-blooded• Have hair or fur• Breathe air through lungs• Bear live young• Nurse their young with milk produced by mammary

glands.• Rely on the ocean for their existence

Evolutionary Lineages1. Cetacea2. Sirenia3. Desmostylia *4. Pinnipedia 5. Ursus maritimus (polar bear)6. Kolponomos (marine bear)*7. Thalassocnus (aquatic sloth)*8. Enhydra lutris (sea otter)9. Lontra feline (marine otter)

Desmostylia

Kolponomos

Thalassocnus

Three Orders of Marine Mammals– Cetacea– Sirenia– Carnivora» Pinnipeds (sealions, walruses and seals)» Polar bear (Ursus maritimus)» Two otters (Endydra lutris and Lontra feline)

Physiologic and Anatomic Features• Locomotion

Torpedo shaped bodiesTail flukes and dorsal fin

• Thermoregulation Fur and Blubber (fat) Circulatory adjustment

• HypoosmosisHighly efficient kidney

Physiologic and Anatomic Features• Diving Mechanisms

Complex Blood Vessel SystemReservoir Organs; Muscles, Blood and SpleenBradycardiaVasoconstriction

• FeedingBalleen PlatesCheek Teeth

Other Characterisrics• Social Animals

• Dolphins- travel in pods• Whales- hunts together

• Communication• Dolphins- coordinated hunts• Humpback Whales- sing to attract females• Female pinnipeds and pups- voice recognition• Whales- warble

Other Characterisrics• Echolocation

They send out rapid sound pulses and listen to their echo to find prey and determine their surroundings.• Toothed Cetaceans- Sperm Whales, Dolphins

• SpeedSea Lion- 35kphOrcas- 50kphDolphins- 64kph(fastest)

Status of Marine Mammals• Endangered and threatened marine mammals

28 speciesBlue whale, Gray whale, Killer whale, Sperm

whale, Spotted seal, Steller sea lion, Indus river dolphin Chinese river dolphin

Marine Mammal Commission• Commission created under title 2 of the Marine

Mammal Protection Act of 1972.• Protection and Conservation of marine mammals.

Order Cetacea

• The order Cetacea includes the marine mammals commonly known as whales, dolphins, and porpoises.

• Fossil evidence suggests that cetaceans share a common ancestor with land-dwelling mammals that began living in marine environments.

• The body of a cetacean is fusiform.

• The forelimbs are modified into flippers

• Tiny hindlimbs are vestigial. The tail has horizontal flukes.

• Cetaceans are nearly hairless, and are insulated from the cooler water they inhabit by a thick layer of blubber.

• Cetaceans breathe air. They surface periodically to exhale carbon dioxide and inhale a fresh supply of oxygen. During diving, a muscular action closes the blowholes.

• Cetaceans can remain under water for much longer periods than most other mammals.

• Cetacean eyes are set on the sides rather than the front of the head.

• Cetaceans also use sound to communicate.

• The toothed whales, such as the sperm whale, beluga, dolphins and porpoises, have teeth they use for catching fish, squid or other marine life.

• Instead of teeth, Mysticeti have baleen plates made of keratin , which hang from the upper jaw.

Suborder Odontoceti (toothed whales)

• highly variable in body shape and size and include dolphins, porpoises, narwhal, beluga, beaked, and sperm whales.

• are generally capable of echolocation. From this, Odontoceti can discern the size, shape, surface characteristics, distance and movement of an object.

Suborder Mysticeti

• Baleen whales include blue, gray, humpback, and bowhead whales.

• Instead of teeth, baleen whales have rows of strong, closely spaced baleen plates along both sides of their upper jaws. Baleen whales breathe though a pair of blowholes.

Order Sirenia

• The Sirenia are an order of fully aquatic, herbivorous mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters.

• Sirenians have major aquatic adaptations: the forelimbs have modified into arms used for steering, the tail has modified into a paddle used for propulsion, and the hindlimbs (legs) are but two small remnant bones floating deep in the muscle.

• The skeletal bones of both the manatees and dugong are very dense.

• The lungs of sirenians are unlobed. In sirenians, the lungs and diaphragm extend the entire length of the vertebral column.

Family Trichechidae

• Manatees are found along the coast of the southeastern US, in the West Indies and adjacent parts of South America, in the Amazon and Orinoco drainages of South America, and tropical west Africa.

• Manatees have a mass of 400 to 550 kilograms (880 to 1,210 lb), and mean length of 2.8 to 3.0 metres (9.2 to 9.8 ft), with maxima of 3.6 metres (12 ft) and 1,775 kilograms (3,913 lb) seen

• They have a large, flexible, prehensile upper lip.

• Their small, widely spaced eyes have eyelids that close in a circular manner. The adults have no incisor or canine teeth, just a set of cheek teeth.

• Generally, manatees swim at about 5 to 8 kilometres per hour (3 to 5 mph). However, they have been known to swim at up to 30 kilometres per hour (20 mph) in short bursts.

Family Dugongidae

• Dugongs are bottom-feeders, grazers on a number of species of aquatic plants. They usually rip the plant from the substrate, swish it gently to remove sand, then eat it

• They are found only in shallow, coastal habitats, where they occur singly or in small groups of 3-6 members.

Order Carnivora

Suborder Pinnipedia

• are "flipper-footed" marine mammals. • Also called “Pinnipeds” • often generalized as seals• There are 33 extant species of pinnipeds, and more

than 50 extinct species have been described from fossils.

Family Otariidae• sea lions and fur seals have visible external ears and

can walk on all four flippers by rotating their rear flippers forward under their body.

• They are more mobile on land than true seals and are often seen in zoos and aquariums. Their swimming power comes from their large front flippers.

Family Phocidae• true seals have no external ears and crawl on land

because their front flippers are small and their hind flippers cannot rotate forward.

• Their swimming power comes from their large, fan-like rear flippers.

Family Odobenidae• walruses are distinctive for their two long tusks. • Walruses inhabit the Arctic seas and ice floes. • They have no external ears, but can rotate their hind

flippers and walk on land. • These pouches can be inflated to hold the head above

water when sleeping or used as resonance chambers to enhance underwater sound.

FISSIPEDS

Family Mustelidae• Sea otters are the only marine member of the

mustelid family, which includes land mammals such as river otters, weasels, and badgers.

• They do not inhabit the open ocean, but instead live among coastal kelp beds, where they dive and hunt for a variety of shellfish and marine invertebrates.

• With their exceptionally thick, dark fur, longer tail, lack of true flippers, and their ability to use a rock as a feeding tool, sea otters are easily distinguished from other marine mammals.

Family Ursidae• Polar bears are designated as marine mammals

because they depend on the ocean for a majority of their food. Thus, they are protected under marine mammal protection laws.

• Polar bears range throughout the Arctic regions, including parts of Alaska and Canada.

Sources:• http://www.marinemammalcenter.org/education/mari

ne-mammal-information/• http://en.wikipedia.org/wiki/Marine_mammal• http://marinebio.org/oceans/marine-mammals.asp• http://www.mmc.gov/• http://www.nmfs.noaa.gov/pr/species/mammals/

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