In the world of seahorses it isn’t the females who get pregnant. When they mate, female seahorses deposit the eggs in the male’s pouch to be fertilised. The male then gives birth to the babies anywhere between nine and forty-five days later.
The process, in fact, makes it look like he’s practically coughing them out.
Why are sea horses the only species known to do this? The theory is this speeds up the process of delivery. Since the female counterpart needs time to produce more eggs, the male takes charge of the fertilisation and incubation. Now that sounds like a fair division of labour.