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JohnHildebrandScrippsInstitutionofOceanography
April13,2018Biogeography,SeaOtters,PolarBears
SIO133– MarineMammalBiology
Marine Mammal ScienceEmerged as a discipline in last 20-30 years
Expansion of literature1495-1840 – 3 papers/year1845-1960 – 28 papers/year1961-1998 – 646 papers/year1999-2004 – 856 papers/year
Marine Mammal Science, Journal of Mammalogy, Canadian Journal of Zoology, Journal of Zoology, Fisheries Bulletin, Marine Ecology Progress Series …..
Marine Mammal ScienceStudy of Mammal Mammals
Increasing technologyRemote sensing
acoustic, satellitetime-depth recorderscrittercams
Molecular ecologysystematicstaxonomy
Physiology
Cosmopolitan speciesKiller whales (Orcinus orca)
From Hoelzel 2002
Migratory speciesn Prey driven: Mysticetes
n Ice driven: polar species – e.g. beluga, narwhal, bowhead
Block et al. 2011
Month of year
Blue whale stocks
From McDonald et al. 2006
Anti-tropical distribution
From Hoelzel 2002
Species distributionn Pan-tropical species
n E.g. Spinner dolphins (Stenella longirostris)
From Hoelzel 2002
Temperature-defined distributionn Short-finned
pilot whales
Source: Duke University,OBIS-SEAMAP
n Long-finned pilot whales
Circumpolar speciesBeluga whales (Delphinapterus leucas)
From Hoelzel 2002
Endemic species - River dolphins
From Hoelzel 2002
Coastal speciesPorpoises
From Hoelzel 2002
Gender-variable distributionSperm whales (Physeter macrocephalus)
Source: whaletrackers.com
Kingdom AnimaliaPhylum ChordataSubPhylum Vertebrata
+ backbone+ dorsal hollow nerve chord+ bone/cartilage internal
skeleton
Marine Mammal Systematics
Class Mammalia, 4000 species•Viviparous•Hair
•Lactation via the mammary gland•4 chambered heart
•Diphyodont dentition- 2 sets of teeth•7 cervical vertebrae•3 inner ear ossicles•Respiratory system- diaphragm•Endothermy
Mam
malian
Orders
Platypus & Echidna
Marsupials
Scaly Anteaters
Armadillos,Sloths, Anteaters
Dogs, Cats, Bears, Weasels, Pinnipeds, Otters
Shrews
ElephantShrews
Rabbits,Hares, Pikas
Mice, Rats
Gorillas,Monkeys, Baboons,Humans
TreeShrews
Flying Lemurs
Bats
Aardvarks
Even-ToedUngulates(Deer, Cows, etc.)
Whales, Dolphins, Porpoises
Odd-ToedMammals (Horses, Rhinos)
Hyraxes
Manatees& Dugongs
Elephants
Marine Mammal Taxonomic GroupingsAbout 126 Species across 3 Orders
Order Carnivoria (38 species)Polar bears, sea otters, seals, sea lions, walruses
Order Cetacea (83 species)Baleen whales, toothed whales
Order Sirenia (5 species)Manatees, dugongs
Order CarnivoriaIncludes 5 Families of Marine Mammals
Mustelidae – Sea otterUrsidae – Polar bearPhocidae – Seals (true seal)Otariidae – Sea lions (eared seals)Odobenidae - Walrus
Family Mustelidae, Subfamily Lutrinae
Enhydra lutris - Sea otter - N. American - Teeth for crushing shells- Fully marine
Lontra felina - Marine Otter- S. American- endangered- exclusively
marine foraging
Body mass: <5 kg in marine otter40 kg in sea otters.
Shortened limbs, Lengthened and often stout tails, Slim and elongated head, neck and body Loosely articulated axial skeleton
gives serpentine appearance
Characteristics of Otters
Depend on dense fur for insulationRequires constant grooming (5-10% time)Enlarged rear flippers for heat lossDive to > 100 mSea otter’s large lung and blood volumes facilitate floatation and oxygen storage
Characteristics of Otters
Enhydra lutris Lutra
Phylogeny of Otters
(1) Old World and sea otter
(2) the New World otter
(3) the giant otter
Family MustelidaeEnhydra lutris
Family MustelidaeLontra felina
Family UrsidaeUrsus maritimus - Polar bear
- Evolved from brown bear
- Teeth more like seals/sea lions thanbears
- Eats arctic seals
- Threatenedw/ climate changedue to diminished sea ice Photo by Ansgar Walk
Phylogeny of Polar Bears
Ursus maritimus - Polar bear range
Polar bear - regions
Durner et al. 2009 Ecological Monographs Vol 79
Diminishing Ice
Durner et al. 2009 Ecological Monographs Vol 79
Tagged Polar Bear 1985-1995
Durner et al. 2009 Ecological Monographs Vol 79
Polar Bear Resource Selection Function
Durner et al. 2009 Ecological Monographs Vol 79
Polar Bear Predicted Change Optimal Habitat
Durner et al. 2009 Ecological Monographs Vol 79
2001-2010to2041 - 2050
Polar Bear body mass decreasing
