Why are sea horse females so virtous? When meeting a male of their liking, the female sea horses will keep the male at bay for several days. requiring him to go through quite an elaborate courtship cycle before mating with him. Googling ”sex-on-first-date” will give you an amazing amount of links discussing the pros and cons of that eternal question. Fish generally tend to be on the more positive side of that issue, with most fish having very little real courtship and seemingly letting mating be a “wham-bam-goodbye” type of experience. As courtship is energetically expensive and quite dangerous, courtship is a somewhat surprising activity in nature. There are some exceptions to the lack of extensive courtship behavior among fishes, though. Notably, most monogamic fish use some time and effort to do at least some amount of courtship behavior, even if it rarely amounts to much.

"Pregnant" common sea horse male

“Pregnant” common sea horse male

Not so for sea horses. They are the really virtous and chaste fishes around. Sea horses often have premating rituals, or courtships, lasting several days. Sea horses are monogamous, and, probably well known to most divers, the males carry the eggs in a pouch for the duration of the egg stage. Mating in sea horses is essentially the opposite of the standard mating system, as females oviposit in the male’s pouch where the eggs are fertilized. This freedom for the female sea horse comes with a price, though, as females must have access to a male pouch within hours of egg maturity. If not she will have to drop the eggs and let them die. As the formation of eggs takes a heavy toll on females, this is obviously something a female sea horse wants to avoid at more or less all costs. Enter courtship. Much as the extensive and very time consuming courtship of small songbirds, courtship in sea horses serves the purpose of making the male invest in pre mating costs, and at the same time keeping him from other females. The several days of courtship in sea horses guarantee the female access to a pouch when her eggs are mature, as a male that have spent that much time investing in the egg batch to come, is unlikely to change his mind in the last minute. Thus, female sea horses by following the “not-on-the-first-date” –rule will force sea horse males into being considerate and responsible caretakers for the eggs.
Juvenile thorny sea horse

Juvenile thorny sea horse

What is the reason for having courtship in fish that are not limited by pouch availability? Well, that will be the subject of a later blog.