I have been reading up about seahorses recently and discovered some interesting little bits of information I could not help but share. While seahorses seem to be a big favourite for divers and non-divers alike, we actually know surprisingly little about them. Some of their strange quirks are well known. The fact that the males get pregnant is probably one of the favourite and most retold bits of knowledge about them. I want to go a bit further and more interesting than that, so let’s get started.
Seahorses belong to the family of Sygnathidae, which translates as “fused jaws”. What this means is that all seahorses and pipefishes have jaws that are stuck together, they can’t open them anymore. So if you were to imagine eating like a seahorse, try gobbling up your salad, steak, pizza, apple,… with clenched jaws, while only using your lips to help you suck the food in. A good thing seahorses do not have teeth, as that would make it even more difficult!
Another quirky thing seahorses do, is that they make noise. They make two distinct types of sounds: “clicking” and “growling”. I absolutely love the idea of a growling seahorse! It seems they do this when they are stressed out and it might even be some sort of escape mechanism to startle predators. Most likely because those predators would be laughing too hard because a seahorse just growled at them… The clicking sounds are mostly used during courtship and mating, so not only do seahorses growl to chase away predators, they also serenade their partners to get them in the right mood. Strange little critters indeed.
To keep up with the strangeness, have you ever wondered how strange the tail of a seahorse actually is? Probably not, I definitely hadn’t before reading this article. The tails of most animals are round, but nearly all seahorses have square tails. As it turns out, this square shape is better at grasping and holding items. At the same time it offers a higher resistance to crushing than a round tail would. So perfect for a camouflaged critter which spends most of its time clinging on to objects, pretending to be something it is not to avoid getting eaten by predators.
The objects seahorses hold onto can be anything, usually they cling on to objects like seagrass, algae, gorgonian seafans, etc. But they do not seem to be very picky at all. This article showed how seahorses living in areas with a lot of plastic actually use that plastic as camouflage. The seahorses even changed their colour to resemble the colour of the plastic and the spots on it. Unfortunately I cannot put the original pictures online due to copyright issues, so if you want to see them, follow this link. Since seahorses don’t really mind what they hold on to, artificial structures can be used to provide habitat for them when their natural habitat has been destroyed. This way populations can continue to exist until the natural vegetation has recovered.
Loss of habitat is one of the risks that endanger seahorses, the trade for traditional Chinese medicine is another big threat to them. IUCN has listed 7 species as Vulnerable and one species as Endangered, but most species have either not been assessed or we lack the data to assess whether or not they are endangered. To combat the illegal trade and offer some means of protection, all seahorses are listed with CITES, which means trading them is strictly controlled. One of the simple rules used to do this, is a size limit of 10cm. This size ensures that most traded seahorse species are mature individuals who can reproduce and that juveniles are left alone.
The fact that we don’t really know how many species of seahorses exist, makes protecting them hard. Estimates of the number of seahorse species range from 40 to 48 species. It is quite likely new species are still waiting to be discovered, though the opposite might happen as well. Two species of pygmy seahorses (Hippocampus severnsi and Hippocampus pontohi) were described in 2008. But recent genetic analyses showed that they are actually the same species which comes in different colour variations.
If you want to know more about seahorses or just have a good laugh, check out this great video from Ze Frank with some more true facts about seahorses.