Birds do it, bees do it, and so do whales (with a taste for the theatrical). The male right whale can boast a twelve foot-long penis and the biggest testicles of any animal on earth - weighing in at one tonne and producing a gallon of sperm.

Watch how this group of southern right whales come up with an impressive solution to one of nature's trickiest manoeuvres for marine mammals - breeding underwater.

From the BBC Earth programme The Life of Mammals.