A few recent studies have focused on their extraordinary reproductive ecology. In syngnathids, only the make becomes pregnant. The evolution of the make brood pouch can be traced across genera, from simple ventral gluing in some pipefishes to the completely sealed seahorse pouch. Females transfer eggs to the male's brood pouch, where they are fertilised, and then provide no further parental care. In terms of their reproductive ecology, the syngnathids studied thus far fall into two broad categories.
Some pipefishes mate promiscuously.
Each female confers eggs on more than one make and males of some species accept partial clutches from more than one female. Neither male nor females hold home ranges and both sexes move large distances. Females compete more intensely than males for mates - and are commonly larger, more colourful and more conspicuous than males. Seahorses and other pipefishes are rigidly monogamous. One male and female mate repeatedly and exclusively with each other and these par bonds are reinforced with daily greetings, occurring shortly after dawn throughout the male's pregnancy.