Pipefishes and seahorses: Are they all sex role reversed?

The male pregnancy of pipefishes and seahorses has led to the inference that females compete most intensely for access to mates, because males limit female reproduction. However, recent work has shown that in different species either sex may be the predominant competitor for mates. In this family, there is an apparent association between the mating pattern and the sex roles: polygamous species show reversed sex roles whereas monogamous species exhibit ‘conventional’ sex roles. These studies emphasize that sex role reversal is not synonymous with male parental care.

Vincent, A.C.J., Ahnesjö, I., Berglund A. & G. Rosenqvist (1992). Pipefishes and seahorses: are they all sex role reversed? Trends in Ecology and Evolution 7:237-241. https://doi.org/10.1016/0169-5347(92)90052-D