Dolpin (7) Flashcards
(30 cards)
What is suggested by the frequent sexual activity among dolphins in terms of social structure?
It may be important for social bonding - similar to primates, sexual activity among dolphins can strengthen relationships within herds.
Why might dolphins and whales breach?
Breaching may provide…
* An airborne view
* Breaching may shake off parasites
* Or it may be a form of play
What is the body shape of Risso’s dolphin?
Stocky from head to large dorsal fin, tapers quickly behind - this unique profile gives Risso’s dolphin an unusual appearance.
- What behavior is noted about Risso’s dolphins?
- What do they possess as a result?
Aggressive or territorial - their bodies often show scratches that match the pattern of their teeth.
- Name a famous Risso’s dolphin
- Why was it famous?
Perolus Jack - he accompanied ships across Cook Strait between 1888 and 1912.
What happened to Pelorus Jack after someone shot at him?
He disappeared for about six months
Upon reappearance, he resumed guiding ships across the strait.
What notable feature of male Risso’s dolphins increases with age?
White scarring all over the body - presumably due to confrontations with other Risso’s dolphins.
True or False: The beak of Risso’s dolphin is visible.
False - the beak is not visible in this species.
What is a characteristic behavior of Risso’s dolphins when swimming around small boats?
They raise their head above the water
How is the blow of Risso’s dolphins described?
Barely discernible - pretty un-unique
What type of leaps do Risso’s dolphins make while swimming?
Spectacular twisting and rolling leaps
Where are Atlantic White-sided dolphins commonly stranded?
In the New England region of the United States.
True or False: Individual and mass strandings of Atlantic White-sided dolphins are rare.
False - strandings of Atlantic white-sided dolphins are common for some reason.
What is the maximum speed of the sei whale, the fastest whale?
24 mph (38 kph)
How do sei whales catch their food?
By swimming on the surface with mouth open, skimming the water
What is the origin of the name ‘sei whale’?
‘Seje’, a Norwegian term for pollack (a type of fish that they love to co-exist with)
How many porpoises (not dolphins or whales) die annually in British waters due to entanglement in fishing gear?
More than ten thousand
Will a cetacean survive if it gets entangled in netting?
No, because they drown.
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What specific threat do bass fisheries in the Western Approaches to the English Channel pose?
Significant threat to the common dolphin population
Where do pollutants accumulate in marine mammals?
They are stored in an inert state in the fat of marine mammals
What happens to pollutants when marine mammals reproduce?
Pollutants are passed directly from one generation to the next through the placenta or within the mother’s milk.
- What by-product of the plastics injury causes issues in marine mammals?
- What specifically do they do?
- Polychlorinated biphenyls (PCBs)
- PCBs can affect reproduction and resistance to disease.
- What significant event occurred among striped dolphins in the Mediterranean during 1989-1990?
- Why did it happen?
- Several hundred striped dolphins died
- Autopsy revealed a morbilli virus infection and high levels of PCBs.
How intense is marine traffic around the British Isles?
Amongst the most intense of anywhere in the world (this high level of traffic contributes to noise pollution).
