Q 01/05

Which competitive swimming stroke is powered by the 'dolphin kick', with both legs beating up and down together?

A) Breaststroke

B) Butterfly

C) Backstroke

D) Sidestroke

Answer · why

B) Butterfly

Butterfly swimmers whip both legs together in a wave modelled on a dolphin's tail; the kick is so effective underwater that racing rules make swimmers...

Q 02/05

For what primary purposes do dolphins use echolocation?

A) Mating and play

B) Warmth and buoyancy

C) Song and communication

D) Navigation and hunting

Answer · why

D) Navigation and hunting

Navigation and hunting both depend on it: a dolphin sends out rapid clicks and reads the echoes, so it can find its way and track prey in dark or murk...

Q 03/05

A dolphin's blowhole is the evolutionary counterpart of which human feature?

A) The ears

B) The nostrils

C) The mouth

D) The tear ducts

Answer · why

B) The nostrils

The nostrils of dolphins' land-dwelling ancestors moved back along the skull over millions of years to become the blowhole, which lets a dolphin breat...

Q 04/05

In a landmark mirror test, what did bottlenose dolphins do after researchers marked their bodies with dye?

A) Charged at the glass

B) Twisted to inspect themselves

C) Fled to a far corner

D) Whistled at their double

Answer · why

B) Twisted to inspect themselves

Twisted to inspect themselves: both dolphins swam to the mirror and turned the marked part of the body toward it, a sign of self-recognition shown bef...

Q 05/05

Which lifelong mark of birth, familiar from the human body, does every dolphin carry on its underside?

A) A birthmark

B) A belly button

C) A whorl of hair

D) A dewclaw

Answer · why

B) A belly button

A belly button marks the spot where the umbilical cord snapped at birth; like every mammal nourished through a placenta, a dolphin keeps the scar for ...