Cetacean And Pinniped Diversity And Adaptions Flashcards
Which class of mammals doesn’t have marine species
Amphibians
Why did vertebrates go back to the marine environment
For the resources they can exploit - food
Problems associated with returning to the sea?
- Still need to breathe air - big problems, have to come back up to surface regularly - wasted time and energy, also might lose prey
Advantages of air over water as respiratory medium
Lower mass
Higher viscosity
High diffusion rate
O2 is easy to access and fairly constant in air
Air has low heat conductivity and low heat capacity (they’re endotherms)
What is the mass differences between air and water?
For equivalent amount of oxygen, animal has to move 25,000 times as much water as air
What is the problem but advantage with waters viscosity?
Much more energy required to move through
But water is supportive therefore less energy needed to support a body
What is positive and negative buoyancy?
Positive is floating, use energy for when they want to dive
Negative is sinking, use energy for when they come up to breathe
What Cetacea have been hunted to extinction?
Atlantic grey whale
Stellar sea cow
What is the global hump back whale population compared to right whale?
60,000, found in every ocean
Compared to 300
What are the general adaptations of cetaceans?
- increased insulation
- circulatory adjustments
- countercurrent heat exchangers
- sensory adaptions
- diving capability
How long can cetaceans live?
18-100+ years
What’s the breeding cycle of Cetacea
1-4 years, 1 calf per breeding event
What are dolphins and porpoises population growth per year
1-4%
What are large cetaceans population growth
1-10%
How is she determined in toothed cetacean mammals?
Growth layers in teeth
How do you measure age in whales that don’t have teeth eg humpback whales
Ear plugs (waxy filling instead of our air filled hole)
What are baleenidae?
Right whales
Have baleen plates hanging from upper jaw
Large mouth
They filter feed at the surface
What characterises the dolphin ideas
Dolphins/orcas
Small and large (2-7m
Echolocate and communicate
Generally non migratoryp
What are the phocoenidae?
Porpoises - 6 species
What mating systems to cetaceans have?
Polygamy and promiscuity
Which whales have low latitude winter breeding grounds? Describe their breeding
Humpback and right
Small groups of females with offspring, escorted by males
Males compete with each other
Females reproduce every 2-4 years, do all the parental care
How do humpbacks and right whales compete for females
Sing songs
What are resident killer whale groups
Matrilineal pods, mature males remain in pod but mate with females in other pods
What 2 examples of large characteristics to attract females in odontocetes?
Killer whale: large dorsal fin
Narwhal: large tusk
Which Odontocete has the largest sexual dimorphism?
Sperm whales, male is twice the size
When do males leave sperm whale pods?
4-5 years old to head north
What does the ‘fission fusion’ group structure in bottlenose dolphins mean?
Groups will come together for certain activities (eg. Breeding) but split into smaller groups for other activities (eg. Foraging)
Which dolphin has 100-1000 in their pods
Spinner dolphins, main pod is split into sub groups of 12-15
How big are harbour porpoise groups?
1-3
What type of odontocetes live in larger groups?
Off shore living
Smaller
Eg. Pilot whales, spotted, spinner and bottlenose dolphins
What are the advantages of large groups?
Protections against predators
Easy to find mates
Cooperative foraging
What are the disadvantages of large groups?
Competition for prey
Risk of inbreeding
Risk of extirpation if subjected to large scale mortality event
What are the family phocidae?
True or earless seals (90%) of all seals 18 species Larger than otaeiidae - monk seals - Antarctic seals - elephant seals - northern hemisphere seals
What are the family otariidae
Fur seals and sea lions
15 species (10 seals and 5 sea lions)
Can walk by turning hind flippers
Shallow divers chasing fast swimming fish
What monk seals are there
Hawaiian monk seal - critically endangered, endemic to Hawaiian islands. 1000 left, declining by 4% because of habitat loss and fishery bycatch
Mediterranean monk seal - large 2.5m/300kg, critically endangered 350-450 left because of human activites (hunting, fisheries)
Caribbean Monk seal - extinct
What is the crab eater seal and how is it doing
Crab eater seal - circumpolar distribution around Antarctica.
Medium sized (2m), slender grey coloured seal. Found on free floating ice packs
Specialised predation of Antarctic krill by adapting sieve like tooth structure
Status: least concern, 7-12 million most abundant seal species in the world
What is the leopard seal and how is it doing
Second largest species of seal in Antarctica
Orcas and large sharks are only natural predators
Sexual dimorphism - females slightly larger
20-30 year lifespan
Shallow water hunter, loose jaw can open 160 degrees to bite large prey
Status: least concern - 300,000
What is the easy way to differentiate between harbour and grey seals?
Harbour seal nostrils are 2 lines, whereas grey seal nostrils are like a V
Where are the 3 distinct populations of grey seals in the north Atlantic?
- Off coast of Canada and Northern USA
- Around UK and Ireland, up to Iceland and Norway
- In the Baltic Sea
In what ways do the 3 populations of grey seals differ?
Genetically
Morphologically
Timing of breeding season
How many grey seals are there
Over 300,000, least concern
What percentage of grey seals breed in the UK?
45% (90% of these are in Scotland, outer Hebrides and Orkney)
What was the uk grey seal population estimated to be in 2007?
206,000
2.8% increase between 2007 and 2008
Where are harbour seals found?
Coastal waters of the northern hemisphere, from temperate to polar regions
How many sub species of harbour seal are there
5
What is the virus that has had a negative impact on harbour seals
Phocine distemper virus
What size are harbour seals?
Males upto 1.9m, 70-150 kg
Females 1.7m, 60-110kg
What is the status of harbour seals
Least concern
350,000 - 500,000 animals
How much of European harbour seal population are in uk
30-40% (85% in Scotland)
How many harbour seals in the UK?
2006-2008 showed 40,000-46,000
Major declines of upto 50% since 2000 in Orkney and Shetland
What is the smallest of the otariids?
Galapagos fur seal
1.5m 60kg
How much of their time do they spend out of water?
70% (most out of any other seal)
What do Galapagos fur seals eat?
Small squids and variety of fish
What is Galapagos fur seal status?
Endangered: gone from 30,000 to 10,000-15,000 in 30 years (largely because of El Niño
What’s in the family odobenidae?
1 species of walrus
What is the distribution of walruses?
Circumpolar arctic and sub arctic
How big are walruses?
Males 3.6m 800-1500kg
females 3m 600-1100kg
What are walrus tusks used for?
Interspecific aggression
Defence against predators
Aid for hauling out on ice
What mating system do walruses have?
Polygamous
What is the status of walruses
Data deficient: current total not known, but maybe 18,000-20,000
What’s the difference between otariid (sea otters and polar bear), phocid and walrus fur?
Otariid fur has 2 layers: guard hairs and underfur hairs
Phocids and walrus lack underfur, instead have blubber
Which animals undergo a full annual moult?
All phocids, sea otter and the beluga whale
What is lanugo?
Baby fur
What limits the distribution of pinnipeds towards the equator?
Temperature, their inability to thermoregulate especially when on land
Why do pinnipeds have delayed implantation of the embryo
Because the point in time at which they can give birth is restricted, if they didn’t delay implantation pup would be born at the wrong time for breeding and weening
