Marine Mammals

Question 1

What is a mammal

Answer 1

A higher vertebrate, well developed brain and neural system, warm blooded with homeostatic control of core body temperature.

Question 2

What are Pinnipeds

Answer 2

Seals, fur seals and walruses

Question 3

What Carnivora

Answer 3

Polar bear and sea otter

Question 4

What are Sirenians

Answer 4

Manatees and Dugong

Question 5

What are Cetaceans

Answer 5

Whales and dolphins

Question 6

How many species of Pinnipeds are there

Answer 6

33

Question 7

What is key adaptation of pinnipeds

Answer 7

Dive to depths of 1500 feet and hold breath for 2 hours

Question 8

What are the distributions of seals

Answer 8

Mainly polar, Arctic and Antarctic

Question 9

Name 2 key adaptations to partial marine life

Answer 9

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.

Question 10

Explain seal reproduction

Answer 10

Sexual - one pup per year - birth on land - create creche for pups

Question 11

What seal has very specially adapted teeth and for what reason

Answer 11

Crabeater seal with series of fine spikes on teeth for sieving out krill

Question 12

Describe polar bear reproduction and relavent adaptations

Answer 12

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.

Question 13

Fun fact

Answer 13

Sea otters have the thickest fur in the animal kingdom but no blubber

Question 14

What is a typical sea otter diet

Answer 14

Mussels, clams, abalone and sea urchine

Question 15

What is a typical sirenian diet and quantity

Answer 15

Adults eat up to 15kg of seagrasses a day.

Question 16

What is a typical manatee reproductive cycle

Answer 16

Gestation is 1 year, mothers will burse young for 2 years, reproduction rate is low - single calf every 2-5 years.

Question 17

What are two threats to manatees

Answer 17

Seabed grass loss; Collisions with boats

Question 18

What is a Mysticeti

Answer 18

Baleen whale

Question 19

What is an Odontoceti

Answer 19

Toothed whale

Question 20

Why is the Odontoceti melon important

Answer 20

Plays a major role in ocholocation

Question 21

Do Mysticeti have echolocation abilities

Answer 21

No

Question 22

Does a Mysticeti or Odontoceti have an asymmetrical skull

Answer 22

Odontoceti

Question 23

Does a Mysticeti or Odontoceti have a symmetrical skull

Answer 23

Mysticeti

Question 24

Give 4 adaptations of Cetaceans to marine environment

Answer 24

Aquatic lifestyle- feed, mate and give birth in water; Complex hunting and feeding methods; Vocalization for communication including echolocation; complex community structure

Question 25

What species of Cetacean use bubblenets for feeding

Answer 25

Humpback whales

Question 26

What species of cetacean use Kerplunking for feeding

Answer 26

Bottlenose Dolphins

Question 27

What species of cetacean use listening for feeding

Answer 27

Killer whales

Question 28

How to Mysticetes feed

Answer 28

They are batch feeders - Gulping through rapid forward movement; suction; skimming (continuous water flow though mouth). Balean plates help to filter krill for consumption.

Question 29

How do Odonticetes feel

Answer 29

Raptorial - grab prey with swimming motion. Or Raptorial suction feeding

Question 30

What are general mysticetes prey

Answer 30

Krill, zooplankton, cephalopds, fish

Question 31

What are general prey of Odontoceti

Answer 31

Cephalopods, fish, benthic invertebrates (species dependent)

Question 32

How do dolphins vocalise

Answer 32

Clicks for echolocation, and whistles for communication - different pod dialects

Question 33

What is different between odontoceti and mysticetes in terms of social grouping

Answer 33

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.

Question 34

How do Mysticetes produce sound

Answer 34

Air moved from lungs through controllable valve - nasal and larangeal sacs asct as resonators

Question 35

How to Odonocetes produce sound

Answer 35

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.

Question 36

What is MLDB

Answer 36

Two sets of monkey lips/dorsal bursa found in dolphin species.

Question 37

What is odontocetes melon structure for

Answer 37

Water is denser than air and sound travells 5 times faster so to aid echolocation the melon focuses sound waves.

Question 38

What are SOFAR zones

Answer 38

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.

Question 39

What are the reasons for migration in species such as fin and blue whales

Answer 39

Migrate from cold waters in southern oceans rich in krill to warmer waters to mate and bear calves

Question 40

Name 4 main threats to cetaceans and other marine mammals

Answer 40

1. By catch from fisheries (porpoises and dolphins). 2. Competition for food 3. Cetacean decompression sickness - linked to active sonar. 4. Diseases