Original air date: 19 December 1990
Selected material
The proportionately longest sex organ in the world
The barnacle, marked at the bottom of the image, being immobile, needs to stretch very far for a mate. It has the proportionately longest sex organ in the world.
Wolves, their genitals being locked together
The wolves’ genitals are locked together until his sperm has managed to reach her eggs
Attenborough and the royal albatross (the last animal of the series)
She’s already a grandmother and the final words are about her
Introducing the next round of the series, starting with the first episode the final words to this one (sitting by a much studied albatross): “This albatross is over 30 years old. She’s already a grandmother, and this year, once again, she’s produced a chick. She’ll devote the next ten months of her life looking after it. She has faced the trials of life and triumphed. For her little two-day-old chick, the trials are just beginning.”