If you’re a seahorse, size matters.
Highly unusual among the animal kingdom, seahorse reproduction requires the male to do most of the heavy lifting: It’s the male that carries the fertilized eggs to term. And while it had long been thought that partner selection among seahorses went according to the well-established pattern of the female selecting from the pool of eager suitors, it’s actually the guys in the seahorse world who get to be fussy.
In their observation of seahorse mating behavior, University of Zurich biologists Beat Mattle and Tony Wilson noted patterns of high selectivity among the guys, with a distinct pattern of preference for larger females. As it turns out, both the number of eggs contained in the clutch as well as the eventual size of offspring produced are directly proportional to the body size of the female seahorse.
It’s not simply the junk in the seahorse trunk. Larger females are more desirable to the males because they are more likely to produce offspring that are greater both in number and in size.
Photo courtesy of Joanne Merriam via Wikimedia Commons.