In seahorses and pipefish, it is the male that gets pregnant and gives birth. Seahorse fathers incubate their developing embryos in a pouch located on their tail. The pouch is the equivalent of the uterus of female mammals. It contains a placenta, supporting the growth and development of baby seahorses. Seahorse dads provide nutrients and oxygen to their babies during pregnancy, using some of the same genetic instructions as mammalian pregnancy.