bbms behaviour

8/6/2019 Bbms Behaviour

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Cetacean Behaviour


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Cetacean social behaviour

Hard to study

Define size and shape of

community Limited idea of sociability

Artificial notions

Animals traveling alone mayhave members of a larger

social unit


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Examples of social units

Grey whale: not very social

migrate in pods =2-5

form larger units in coldwater feeding areas and

calving lagoons


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Blue whale: travel in close nit groups of 2-4 Larger herds in feeding areas

Fin Whales: travel in herds of 3-20

High # when feeding on krill


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Minke whales: roam alone or in groups of 2some times congregate at edge of pack ice to

feed

Humpback whales : pods of 2-3


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Definitions

Pod: group of whales, dolphins, or

porpoise which can be quite complex

(Some only form pods for short times)

Breaching: leap from water and fall

back with a splash ( reason unknown)

36 ft whale 17 miles/hr

swim parallel to surface than raises fluke

and tilts upward


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Definitions

Spy hopping : whales or dolphins raisetheir heads out of the water for short

periods of time (take a look around)

Lobtailing or tail slapping: raise flukes

and forcefully slaps the water

can be heard for 7rl miles common in humpbacks, grey & right

whale

aggression or warning display

(communication)


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Definitions

Flipper slapping: whale lies on its

side and and lifts its pectoral

fins out of the water and slaps it

down creating a cracking noise

Bowriding: dolphins place

themselves in the wave created

by boats


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Definitions

Logging : whale lies still or near the surface for

an extended period of time

Believed to be a resting behaviour or maybe

sleeping

catnaps with brain function


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Baleen whales

Less social than odontocetes; form loose

aggregations

Seasonal breeding aggregations with intense

social activity

Often in small pods (less than 12)

Some work cooperatively to feed


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Baleen whales

Song

Tropics: male humpbacks sing loud and long andrepeat units of song that last 2-20 min

Song use: declare territory or lure females or both

Theory: song length shows males strength & Advertisemating ability

Next winter: sing version of song from last season withmodifications ( pick up from last year)

Usually Stop singing after breeding


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Odontocetes

Complex social structure fromsolitary beaked whales - true

oceanic dolphins pods

Organization depends on where

they live Ex. River dolphin: single or small

groups

Near shore= small pods

Oceanic= large schools (100s- 1000s)

e.g. spinner and spotted dolphin


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Odontocetes

Many dolphin pods = females and their

offspring

Often both subadult males and females leavegroups but females return when they bear 1st

calf

Males buddy up, and travel outside of female

home range, joining females to mate


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Odontocetes

3 types of societies

1. Nuclear group- single adult males with females

2. Nursery groups- adult females and their young

3. Bachelor group variable # of adult and subadult

males


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Faroe Island Pilot Whales

Males in pods are not the fathers of pod calf's

Males and females never leave mothers pod therefore 2 or

more pods converge for brief matting's ( limits inbreeding )

Males are larger than females and have a more bulbous head


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Faroe Island Pilot Whales

Grandmothers

Post reproductive females that are still lactating

B

aby sitters Pilot whales are deep feeders therefore they may be

feeding calves that cant dive while mothers feed

Only other group of whales that do this is the sperm

whale

Not all grandmothers lactate

Repository of cultural information e.g. locations of

feeding grounds (long term memory of specific

feeding grounds)


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Sperm whales

Sexualy dimorphic, deep divers

Females: 40 ft

Males: 60 ft and 3X the weight

Essentially a matriarchal system

Nursery group or schools: stable groups of 10-

20 mothers, nursing young and immature

calves of both sex (tropical and temperate)


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Sperm whales

Mature males leave group and form Bachelor

pods At 20-25 yrs males are solitary or in pairs

In autumn fully grown males return to warmer

waters to mate (move from one nursery groupto another ~ 6hrs)

Harem: Nursery schools with a visiting bull


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Social Harmony ?

Care for injured pod members

Most are aggressive at times: establishpecking order

Scars on animals of all ages showing fights

E.g. humpbacks:Males will often escort

females that have recently given birth andmay be ready to mate, and will fight off othermales


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Social Harmony ? beaked whales:

beaked whales: 19 sps ranging from 14-40 ft

Sexualydymorphic : males have pair of large teeth

in lower jaw that erupt at puberty

Males have scars

Many males grow dense bones on their snout for

protection during fights


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Social Harmony ?

E.g. Narwhal :

Sexually dimorphic teeth: males have tusk ~ 9ft

(upper left tooth)

Observed tusk threats or fights with males

Do NOT stab each other


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Social Harmony ? Small toothed

whales

Formal organization

When on the move, small closely related groups will adopt

geometric formation

e.g. wedge shape with dominant animals in the lead andyoung protected at the center

If an unknown is ahead, a dominant individual will investigate


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Social Harmony ? Small toothed

whales

Feeding is less formal

Co-operative hunting and corralling prey

E.g. killer whales = well organized hunting

Organize groups into respiratory units which ensurethat no member is ever breathing alone

Herding of salmon into tight ball and take turnsfeeding

Tilt ice floe (seal)

They appear to remain in contact with each otherthroughout the hunt


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Maternal Behaviour

All cetaceans take great care of offspring

Constant surveillance until weaning

Nursemaids

3 examples of care behaviour

1. daisy formation to protect injured pod member

2.distress, it will place itself danger and/or push injured

member away from danger

3. support so injured can breath


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bbms behaviour

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