Male pregnancy. A long, tube-shaped mouth with no teeth. A body covered with bony plates. These are the odd, quintessential features of seahorses, but why? Scientists dove into this question on Wednesday by publishing the first complete sequence of a seahorse genome. “We have discovered an array of changes in the genome, which helps to explain why the seahorse looks the way it does,” said Byrappa Venkatesh, a study co-author and molecular biologist with the Agency for Science Technology and Research (A*STAR) in Singapore. What they found explains many of the creature’s oddities. For instance, seahorses are missing “P/Q-rich SCPP” genes, which cause minerals to collect into teeth. This toothy void may explain why seahorses develop their narrow, straw-like mouths.