Mammals

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Mammals

• Mammal- Any of various warm-blooded vertebrate
  animals of the class Mammalia, characterized by
  a covering of hair on the skin and, in the
  female, milk-producing mammary glands for
  nourishing the young.

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Marine Mammals

• Have similar adaptations for the marine
  environment
• Body Size
• Streamlined Shape
• Insulation
• Dense fur or blubber
• Modified skeleton
• Shortening of appendages
• Loss of hind limbs
• Similar Physiological Adaptations
• For diving, thermoregulation, osmoregulation,
  communication and orientation

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Marine Mammals

• Have similar habitat requirements
• Require the aquatic habitat for survival
• They can therefore be used as indicators of
  habitat degradation.
• Many have been exploited by humans to the point
  of near extinction

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Types of Marine Mammals

• Three Orders
• Carnivora- The mammalian carnivores, includes
  cats and dogs
• Suborder Pinnipedia (fin-footed)
• Other Marine Carnivora
• Family Ursidae Polar Bears
• Family Mustelidae Otters
• Cetacea- Whales dolphins and porpoises
• Sirenians- Manatees and Dugongs

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Marine Carnivora

• Suborder Pinnipedia (fin-footed)
• Most marine of the Carnivora
• Use fat and/or fur for insulation
• Deep divers
• Must return to land in order to give birth
• Ex Seals, Sea lions and walruses

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Sea Lions

• Family Otariidae
• Sea lions and fur seals
• The Eared Seals
• Hind flippers rotate under the body to permit
  walking or running on land
• Swim by using the large fore flippers
• Dense fur that consists of long, coarse hairs and
  thick underfur in which air is trapped to promote
  insulation
• Tend to have a temperate-to-subtropical
  distribution

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Sea Lions
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True Seals

• Family Phocidae- True Seals
• Lack ears, sometimes called earless seals
• Unable to rotate the hind limbs forward under the
  body and therefore dont move well on land.
• Swim by using the hind flippers.
• Small pectoral flippers are used for steering.
• Blubber is used for insulation
• Excellent diving abilities
• Phocids are relatively large compared to Otariids
• Phocids are found throughout the worlds oceans

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Seals
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Walrus

• Family Odobenidae
• Walruses
• One species, Odobenus rosmarus
• Large tusks
• Can rotate hind flippers under the body
• Use both front and hind flippers to swim
• No external ear
• Naked skin with only a few sparse hairs

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Walrus
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Other Marine Carnivora

• Family Ursidae
• Polar Bears
• Found only in the Arctic

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Other Marine Carnivora

• Otters
• Sea otters of the pacific coast of N.America and
  Russia
• Marine Otter of Chile and Peru
• Extremely dense fur
• Flattened hind feet for propulsion in water
• Axillary flap of skin to hold or store food and
  tools
• Horizontally flattened tail

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Sea Otters
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Cetaceans

• Cetacea- Whales dolphins and porpoises
• All are large, ranging from 2m to gt30m
• Streamlined body form with minimal protuberances
  that could cause drag
• Ex They all lack external ears, reproductive
  organs, appendages and are generally hairless
• Vestiges of the pelvic girdle
• Some have hair during fetal development
• Elongated skull with overlapping bones
• Dorsal positioning of the blowhole
• Subdermal blubber that can be 10s of centimeters
  thick.
• Porous, oil-filled bones

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Cetacean Evolution

• Evolved from ariodactyls, even-toed ungulates
  such as cows or pigs
• Multiple stomach compartments
• Like cows

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Two Suborders of Cetaceans

• Mysticeti
• Baleen Whales
• 11 Species
• Odontoceti
• Toothed Whales
• 64 species

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Mysticeti

• Have baleen- a keratin-based brushlike adaptation
  suspended from the upper jaw
• Dorsally symmetrical skull
• Two blowholes
• Non fused mandible
• Tend to be large
• Smallest mystecete, the Pygmy Right Whale is gt6m

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Mysticeti Families

• Family Balaenidae
• 4 SpeciesN. and S. right Whale, Bowhead and
  Pygmy Right Whale
• Extremely convex profile of upper surface of
  skull
• No dorsal fin
• No gular grooves
• Family Balaenopteridae
• 6 species Blue, Fin, Sei, Brydes, Minke and
  Humpback
• Flat profile to skull
• Small triangular dorsal fin
• Numerous gular grooves run from the snout to
  umbilicus
• Family Eshrichtiidae
• 1 species Gray whale
• slightly convex profile to skull
• no dorsal fin aseries of Knuckles above the
  audal peduncle
• 2-4 short gular grooves benthic feeder

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Family Balaenidae
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Family Balaenopteridae
Blue Whale
Minke Whale
Fin Whale
Humpback Whale
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Family Eshrichtiidae

• Gray Whales

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Odontoceti (toothed whales)

• Odontoceti (toothed whales)
• Possess teeth in one or both jaws.
• Dorsally asymmetrical skull
• A single blowhole
• Fused mandible
• Vary in size
• Some dolphins are lt2m
• The sperm whale is 18m

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Family Physeteridae

• 3 Species Sperm whale, Pygmy and Dwarf sperm
  whale
• Dorsal hump or small dorsal fin
• Large bulbous head with spermaceti organ
• Flukes notched
• Well developed conical teeth in lower jaw only,
  fit into sockets in upper jaw

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Sperm Whale
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Family Ziphiidae

• 18 species Beaked whales
• 2 gular grooves
• Small dorsal fin
• Slender rostrum (beak)
• Flukes not notched
• 1-2 pairs of teeth confined to lower jaw

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Beaked Whale
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Family Monodontidae

• 3 Species Beluga, Narwal, and Irrawaddy Dolphin
• Generally no dorsal fin or small dorsal fin
• Head blunt, no beak
• Flukes notched
• All cervical vertebrae free

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Belugas
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Family Platanistidae

• 5 Species River Dolphins
• Small dorsal fin
• Jaws form a long beak
• Flukes notched
• Many well developed conical teeth in both jaws

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River Dolphins
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Family Delphinidae

• 32 Species Dolphins, including the Orca
• Large dorsal fin (except right whale dolphin)
• Jaws form a beak or head gibbose (hump)
• Flukes notched
• Well developed conical teeth in both jaws or in
  lower jaw only

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Dolphins
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Family Phocoenidae

• Porpoises
• 6 Species Dorsal fin large and triangular
• Head blunt, no beak
• Well developed to poorly developed spatulate
  teeth in both jaws

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Porpoises
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Sirenians- Manatees and Dugongs

• Evolved from elephants and other subungulates
• Skin lacks hair
• Well developed vibrissae (whiskers)
• Well developed layer of fat
• Pectoral limbs modified as flippers
• Hind limbs absent
• Tail modified into flukes
• Ears absent

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Family Dugongidae

• 1 Species Dugong dugon
• Nails absent
• Tail modified into notched flukes
• Male and female approximately the same size

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Dugong
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Family Trichechidae

• 3 Species of Manatee
• Vestigial nails present
• Tail modified into rounded paddle
• Male and female approximately the same size

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Manatees