Download Order Sirenia “Sea Cows”

Marine Mammals
Marine Mammals
“... Hmmm...Bottlenosed Bruises, Blowhole Burns, flipper prints, This looks
like the work of rowdy teens, Lou cancel the prom ... .” – Chief Wiggum
What are marine mammals?
Mammals that live and feed in the marine (aquatic)
environment
What are Mammals?
Mammary glands – nurse young with milk
Hair
Diaphragm
Are Cetaceans Mammals?
Class Mammalia
Order Carnivora
Polar bears, sea otters, seals, sea lions,
walruses
Order Sirenia “Sea Cows”
Manatees, dugongs
Order Cetacea
Baleen whales, toothed whales (e.g.
sperm whale, dolphin, beluga, porpoise)
Polar Bear, Polar Bear,
What Do You Hear?
Order: Carnivora
Suborder: Fissipedia (cleft foot)
Family: Ursidae (Polar bear)
Better viewed as a wateradapted terrestrial mammal
Sustained swimmers
Hollow (transparent) hair
fibers too buoyant for diving
Sea Otters!
Order: Carnivora
Suborder: Fissipedia (cleft foot)
Family: Mustelidae (Sea otter)
- Keystone predator in kelp
ecosystems
- Feed on urchins & abalone
- Fur for thermoregulation –
150,000 hairs/cm2
- Near TNZ – rely upon
“heat increment of feeding”
- eat > 25% of body wt / day
Suborder Pinnipedia
“feather-footed” – 3 families
34-36 species – (25% of marine mammals)
Phocidae – (true seals)19 spp.
Otariidae – (sea lions, fur seals) 14-16 spp.
Odobenidae – (walrus) 1 sp.
Seal or Sea Lion???
e.g. Steller sea lion, California sea lion,
Galapagos fur seal, Northern fur seal,
e.g. Harp seal, Northern elephant
seal, Hawaiian monk seal
Hawaiian Monk Seals
3 Monk seal species (Caribbean & Mediterranean)
All critically endangered (H & M) or thought to be extinct (C)
Most primitive phocids
More sensitive to human intrusion than other seals
Population numbers are low (<1,500) and are decreasing due
to:
- death from predation by sharks
- lower pup survival as the result of human disturbances
- ciguatera intoxication
- entanglement in fishing nets and debris
- “mobbing” behavior
- genetic bottlenecking – reduction in allele
frequency (genepool) due to low number of individuals
- disease
Order Sirenia “Sea Cows”
Tropical/subtropical in shallow water
Less sophisticated social behaviors than cetaceans
Less specialization for aquatic existence
Family Trichechidae
Manatee (3 spp)
Family Dugongidae
Dugong (1 sp)
All endangered
Order Cetacea
“All he does is lie there like an unemployed whale.” – Bart Simpson
2 Suborders:
Mysticeti – baleen whales (12-14 species)
blue, humpback, grey whales
Odontoceti – toothed whales, dolphins,
porpoises (≈ 75 species)
Earliest recorded marine mammals
Most diverse & adapted - marine existence
Order Cetacea
“Oh, who thought a whale could be so heavy?! Cheese it! The feds!”
– Moe Syzlak
Mysticeti:
Loss of teeth (except in embryonic stages)
2 blowholes; symmetric skull
Development of large body size & heads
Shortening on intertemporal region & neck
Odontoceti:
Presence of teeth in adults
Telescoping of rostrum; Presence of melon
Single blowhole; Skull & soft-tissue asymmetry
Order Cetacea
“Oh, who thought a whale could be so heavy?! Cheese it! The feds!”
– Moe Syzlak
Mysticeti:
Loss of teeth (except in embryonic stages)
2 blowholes; symmetric skull
Development of large body size & heads
Shortening on intertemporal region & neck
Odontoceti:
Presence of teeth in adults
Telescoping of rostrum; Presence of melon
Single blowhole; Skull & soft-tissue asymmetry
Order Cetacea
Mysticete
Odontocete
Mysticetes
“They like you very much, but they are not the hell your whales.” – Mr. Spock
Class: Mammalia
Order: Cetacea
Suborder: Mysticeti
Family: Balaenidae (3 species – N. & S.
right whales (Eubalaena), bowhead (Balaena)
Family: Neobalaenidae
(pygmy right whale)
Family: Balaenopteridae
(blue, fin, sei, Bryde’s, minke, humpback)
Family: Eschrichtiidae (gray whale)
Suborder Odontoceti
“You know its the largest mammal on earth but
as George says ‘they don't have to be’.” – Jerry Seinfeld
Sperm whale
(1)
Pygmy/dwarf
Sperm whales
(2)
(1)
Ganges River Dolphin
(21)
Beaked Whales
(1)
Baiji River Dolphin
(1)
Bouto River Dolphin
(1)
Franciscana R. Dol.
(2)
Narwhal/Beluga
Oceanic Dolphins
(36)
(6)
Porpoises
Porpoise vs. Dolphin
“Oooh. You're not sharks. You're dolphins. The clowns of the sea”. – Lenny Leonard
Marine Mammals
Adaptations to an Aquatic Existence
Insulated skin – blubber or dense fur
Countercurrent heat exchange systems
Eyes, nose, ears – terrestrial, FW, SW
High Frequency sounds
Adaptations to an Aquatic Existence
Insulated skin – blubber or dense fur
Insulative value a function of thickness, lipid
content, & peripheral blood flow
Skin
Skin
Blubber
Blubber
Muscle
Blubber
Muscle
Muscle
Cetacean/Pinniped
Manatee
Counter Current Heat Exchangers
Heat is conserved before it is lost at the extremity
Parallel intermingling vessels
= vascular bundles (rete)
39°C 37°C 35°C 33°C 31°C
29°C
27°C
28°C
38°C 36°C 34°C 32°C 30°C
Veins
Artery
Adaptations to an Aquatic Existence
Modified limbs – fore & hind limbs, tail
Bowhead Whale
Sea Lion
Manatee
Flippers & Locomotion
In cetaceans, pinnipeds, sirenians –
forelimb proportions altered
Pectoral fin is forearm & hand – elbow not
external
Also seen in marine reptiles, ichthyosaurs,
mosasuars
Pilot
Whale
Blue
Whale
Right
Whale
Marine Mammals
Relating Evolutionary Events