For most men, the thought of taking on the burden of pregnancy from their partners would seem like a nightmare, but it’s all part and parcel of seahorse life. After mating, female seahorses and pipefish lay their eggs into a special pouch in the male’s belly and he carries the developing babies to term. They may seem like a shoe-in for a Dad-of-the-year award but this apparent display of paternal perfection has several macabre twists.

A recent study showed that pregnant pipefishes can also become vampiric cannibals, absorbing some of their brood for nutrition if their own food supplies are running low. Now, Kimberley Paczolt and Adam Jones from Texas A&M University have found that male pipefishes