Emperor Penguins, the subject of the popular 2005 documentary March of the Penguins, have a strange “marriage”.
Penguin couples spend their lives apart from each other and meet once a year in late March, after traveling as far as 70 miles (112 km) inland - on foot or sliding on their bellies! - to reach the breeding site.
Once there, penguins look for their mates by making a bugling call. Male penguins generally stay in one place, lower their head to their chest and call out to the females. Once they find one another, they would stand breast to breast, repeatedly bow to each other and sing (okay, “bugle”).
Now, onto the mating itself: Like in most birds, penguins have no external genitalia. That’s right, male penguins don’t have penises and the females don’t have vaginas. The male’s sperm is produced in the testes and stored in his cloaca (kind of an all purpose orifice for defecating, urinating, and reproduction). The female also has a cloaca that leads to the ovaries. The female penguin lies flat on the ground and the male penguin presses his cloaca onto hers and passes the sperms through.
Once the egg is laid, the female Emperor Penguin transfers it very carefully to her mate (if the egg touches the ice, it would freeze and die), who then keeps the egg warm by tucking it under a large fold of skin until it hatches. The female penguin immediately returns to the sea to feed, leaving the male without food for about two months. The male penguins would huddle together in large groups to conserve body heat in the cold and harsh environment, where winds can reach up to 120 mph (200 km per hour). When the female returns, she finds her mate (and chick) by listening to one particular bugle over thousands other.
When it was released, March of the Penguins sparked a controversy when the Christian right claimed it as a parable of monogamy amongst other things. Turns out, Emperor Penguins are serially monogamous – meaning that for that breeding season, they only have one mate. However, if they can’t find one another the next season (and most can’t – only about 15% of pairs find each other in subsequent year, and just 5% in the third year) they will choose new mates.