Q 01/05

Which thick layer under the skin keeps whales and seals warm in icy seas and helps them float?

A) Cartilage

B) Blubber

C) Lanolin

D) Collagen

Answer · why

B) Blubber

Blubber can be more than 30 centimetres thick on the biggest whales and make up as much as half of an animal's body mass at some points in its life.

Q 02/05

Which ocean giant, whose heart alone can weigh about 180 kilograms, is the largest animal known ever to have existed?

A) Fin whale

B) Whale shark

C) Blue whale

D) Right whale

Answer · why

C) Blue whale

The blue whale reaches about 30 metres and 200 tonnes, yet it lives almost entirely on tiny shrimp-like animals strained from the sea.

Q 03/05

Which Arctic whale carries a long spiral tusk that is really a canine tooth growing out through the upper lip?

A) Minke whale

B) Pilot whale

C) Sei whale

D) Narwhal

Answer · why

D) Narwhal

The narwhal's tusk fed a medieval belief that it was the horn of the legendary unicorn. Females rarely grow one, and a few males grow two.

Q 04/05

Which marine mammal is a keystone species of kelp forests because it eats the spiny urchins that graze them bare?

A) Sea otter

B) Harbor seal

C) Fur seal

D) Manatee

Answer · why

A) Sea otter

The sea otter also has the densest fur of any animal, and it is one of the few mammals to use tools, cracking open shells with rocks.

Q 05/05

Which Arctic hunter of seals is counted as a marine mammal because it depends so heavily on the ocean?

A) Arctic fox

B) Arctic wolf

C) Polar bear

D) Wolverine

Answer · why

C) Polar bear

The polar bear's scientific name, Ursus maritimus, is Latin for 'sea bear'. One study found the bears swimming for an average of 3.4 days at a stretch...