Cetacean Adaptations II

Question 1

How often do female mysticetes usually breed?

Answer 1

Every 2-4 yrs

Question 2

What are the 3 different types of killer whales?

Answer 2

Resident, transient and pelagic

Question 3

What is the social structure in mysticetes?

Answer 3

Small groups of females and offspring- the males ‘escort’ the females

Competitive groups with several males trying to get access to one female during breeding season

Question 4

What could the function of the large dorsal fins on a killer whale be?

Answer 4

Secondary sexual characteristic

Question 5

Do Odontoceti offshore types generally live in large or small groups?

Answer 5

Larger group sizes

Question 6

What type of group structure do bottlenose dolphins have?

Answer 6

A “fission-fusion” where they split up and come together for certain things e.g. they all come together for feeding

Question 7

What is infanticide?

Answer 7

Where the mother kills her offspring within a year of birth

Question 8

How many individuals can be in a group of spinner dolphins?

Answer 8

100-1000

Question 9

How many individuals of harbour porpoise are there usually in a group?

Answer 9

1-3

Question 10

What are the advantages of living in large groups?

Answer 10

Protection against predators

Easy to find mates

Cooperative feeding

Question 11

What are the disadvantages of large groups?

Answer 11

Competition for prey

Risk of inbreeding

Risk of extirpation (group being killed) I’d subject to a large scale mortality event e.g disease outbreak

Question 12

What are phocidae and what percentage of the group do they make up?

Answer 12

True or earless seals

90% of all seals

Question 13

How many species of monk seals are there? Name them:

Answer 13

3
Hawaiian (Monachus schauinslandi)

Mediterranean (Monachus monachus)

Caribbean (Monachus tropicalis)

Question 14

How many individuals are remaining in the Hawaiian species?

Answer 14

1000

Question 15

What size and weight are the Hawaiian species?

Answer 15

2m and 150-300kg

Question 16

What species of monk seal is the most critically endangered and what one is extinct?

Answer 16

Mediterranean= most critically endangered

Caribbean= extinct in 2008

Question 17

How many individual Mediterranean monk seals are left?

Answer 17

350-450

Question 18

What size and weight are the Mediterranean monk seals?

Answer 18

2.5m and 300kg

Question 19

What is the reason for the decline in all the monk seal species?

Answer 19

Disease and human activities: hunting and fishery bycatch

Question 20

What is the most abundant seal species in the world? How many are there?

Answer 20

Crab eater seal (Loboden carcinophagus)

7-12 million

Question 21

Where are crabeater seals found?

Answer 21

Free floating pack ice that extends seasonally out from the Antarctic coast

Question 22

What is the most likely reason for the success of the crabeater seal?

Answer 22

It’s specialised predation on the abundant Antarctic krill, which it has uniquely adapted a sieve like tooth structure

Question 23

What is the second largest species of seal in the Antarctic after the elephant seal?

Answer 23

The leopard seal (Hydrurga leptonyx)

Question 24

What adaptation allows the leopard seal to bite larger prey?

Answer 24

It has an unusually loose jaw that can open 160 degrees

Question 25

What is an important prey for leopard seals and what percentage of pups do they eat?

Answer 25

Crabeater seal

80%

Question 26

How many distinct populations of grey seal are there in the North Atlantic region?

Answer 26

3

Question 27

What are the 3 distinct populations of grey seal?

Answer 27

Canada and northern USA

Eastern Atlantic (UK, Ireland up to Iceland and Norway)

Baltic Sea

Question 28

Approximately what percentage of the worlds grey seals breed in the UK?

Answer 28

45%

Question 29

What are the most widespread of the Pinnipedia?

Answer 29

Harbour seals (Phoca vitulina)

Question 30

How many sub species of harbour seals are there?

Answer 30

5

Question 31

What causes the major population crashes in harbour seals?

Answer 31

Disease

Phocine distemper virus

Question 32

Approximately what percentage of European harbour seals are found in the UK?

Answer 32

30-40%

40,000-46,000 individuals

Question 33

What type of seal is in the family otariidae?

Answer 33

Galapagos fur seal (Arctocephalus galapagoensis)

Question 34

What percentage of a Galapagos fur seals time do they spend out of the water?

Answer 34

70%

More than any other seal

Question 35

What is the current abundance of Galapagos seal estimated to be and what rate is it declining?

Answer 35

10,000-15,000

50% decrease

Question 36

What family are walrus in?

Answer 36

Odobenidae

Question 37

What are the tusks of a walrus used for?

Answer 37

Intraspecific aggression, defence against predators and as an aid for hauling out of ice

Question 38

What are the two layers of hair in otariidae?

Answer 38

Outer protective guard hairs

Inner soft under fur hairs

Question 39

What do phocid and walrus have instead of under fur?

Answer 39

Blubber

Question 40

What groups/species undergo an annual moult?

Answer 40

Phocid seals, sea otter and beluga whale

Question 41

What do fur seals, sea lions and seals do when temperatures are high?

Answer 41

They enter the water or rest in tide pools or caves

Question 42

What species can have delayed implantation?

Answer 42

Pinnipeds, sea otters and polar bears

Question 43

What does the nursing period range from?

Answer 43

4 days in hooded seals to several years in some otariids