Marine Mammals Flashcards
What is a mammal
A higher vertebrate, well developed brain and neural system, warm blooded with homeostatic control of core body temperature.
What are Pinnipeds
Seals, fur seals and walruses
What Carnivora
Polar bear and sea otter
What are Sirenians
Manatees and Dugong
What are Cetaceans
Whales and dolphins
How many species of Pinnipeds are there
33
What is key adaptation of pinnipeds
Dive to depths of 1500 feet and hold breath for 2 hours
What are the distributions of seals
Mainly polar, Arctic and Antarctic
Name 2 key adaptations to partial marine life
Temperature control though fatty oil rich blubber, (energy and insulation). Constriction of capillaries in blubber and skin to reduce blood supply to periphery to reduce heat loss.
Diving adaptations - breath holding ability due to high oxygen store in blood and body tissues and ability to slow the heart.
Explain seal reproduction
Sexual - one pup per year - birth on land - create creche for pups
What seal has very specially adapted teeth and for what reason
Crabeater seal with series of fine spikes on teeth for sieving out krill
Describe polar bear reproduction and relavent adaptations
Breed in feb-may solitary males seek out females. 2-3 cubs that need high protein and high energy diet from rich milk to seal.
Fun fact
Sea otters have the thickest fur in the animal kingdom but no blubber
What is a typical sea otter diet
Mussels, clams, abalone and sea urchine
What is a typical sirenian diet and quantity
Adults eat up to 15kg of seagrasses a day.
What is a typical manatee reproductive cycle
Gestation is 1 year, mothers will burse young for 2 years, reproduction rate is low - single calf every 2-5 years.
What are two threats to manatees
Seabed grass loss; Collisions with boats
What is a Mysticeti
Baleen whale
What is an Odontoceti
Toothed whale
Why is the Odontoceti melon important
Plays a major role in ocholocation
Do Mysticeti have echolocation abilities
No
Does a Mysticeti or Odontoceti have an asymmetrical skull
Odontoceti
Does a Mysticeti or Odontoceti have a symmetrical skull
Mysticeti
Give 4 adaptations of Cetaceans to marine environment
Aquatic lifestyle- feed, mate and give birth in water; Complex hunting and feeding methods; Vocalization for communication including echolocation; complex community structure
What species of Cetacean use bubblenets for feeding
Humpback whales
What species of cetacean use Kerplunking for feeding
Bottlenose Dolphins
What species of cetacean use listening for feeding
Killer whales
How to Mysticetes feed
They are batch feeders - Gulping through rapid forward movement; suction; skimming (continuous water flow though mouth). Balean plates help to filter krill for consumption.
How do Odonticetes feel
Raptorial - grab prey with swimming motion. Or Raptorial suction feeding
What are general mysticetes prey
Krill, zooplankton, cephalopds, fish
What are general prey of Odontoceti
Cephalopods, fish, benthic invertebrates (species dependent)
How do dolphins vocalise
Clicks for echolocation, and whistles for communication - different pod dialects
What is different between odontoceti and mysticetes in terms of social grouping
Odontoceti form pods - (killer whales have long lasting social structures with related pod members). Mysteciti however are generally solitary but may form feeding groups like Humpback whales for short periods.
How do Mysticetes produce sound
Air moved from lungs through controllable valve - nasal and larangeal sacs asct as resonators
How to Odonocetes produce sound
Not well understood. In dolphins from two pairs of phonic lips in the nasal passanges (monkey lips) connected to the dorsal bursa which vibrates when air passes through monkey lips.
What is MLDB
Two sets of monkey lips/dorsal bursa found in dolphin species.
What is odontocetes melon structure for
Water is denser than air and sound travells 5 times faster so to aid echolocation the melon focuses sound waves.
What are SOFAR zones
Sound speed is a function of water temperature - this is a function of depth due to density increase with depth and salinity. Ocean water stratification from warming produces distinct layers around the thermocline. The buffer zone of the metalimnion just below the thermocline is good for transmitting sound waves over long distances due to refraction - this is used by marine mammals to transit whale song for long as possible.
What are the reasons for migration in species such as fin and blue whales
Migrate from cold waters in southern oceans rich in krill to warmer waters to mate and bear calves
Name 4 main threats to cetaceans and other marine mammals
- By catch from fisheries (porpoises and dolphins). 2. Competition for food 3. Cetacean decompression sickness - linked to active sonar. 4. Diseases
