Ever see a seahorse give birth?

Us neither . . . but here are a couple of photos and a vid, whether you need it or not. He’s also the dad btw.

This is one from the mysterious ocean file and the strange world of seahorses:

FROM NAT GEO:  

The head of a horse, the independent swivel-eyes of a chameleon, the pouch of a kangaroo, and the prehensile tail of a monkey: Meet the seahorse. 

Oh, it also doesn’t have a stomach. Or scales. And the males give birth instead of the females. 

We all know what seahorses are, but we don’t really know what they’re about. Where all do they live, exactly? And how are they doing? 

Not knowing these answers is a problem for a fish that’s so exploited. Commercial fishing operations scoop up at least 76 million seahorses a year, and some 80 countries are involved in trading them, according to estimates from the conservation group Project Seahorse. They’re usually caught by accident—mixed in with the more valuable target fish - but then they’re set aside and dried, to be sold for traditional medicine or trinkets. 

When it comes to bending gender stereotypes, seahorses and their relatives would have to be one of the most extreme examples. These fish swap the traditional roles of mums and dads as they are the only animals where the males get pregnant.

The sperm-producers are also the ones that get pregnant. The female transfers her eggs to the male’s abdominal pouch, made of modified skin. The male releases sperm to fertilise the eggs as they enter, before incubating them for 24 days until they are born.

FROM THE CONVERSATION:

In new research published this week in Molecular Biology and Evolution, our team investigated whether male seahorses contribute more to their offspring than just sperm and a container to gestate the embryos.

We took samples from male pouches at different stages of pregnancy and then used new DNA sequencing technologies to assess how pouch gene expression changes.

This is the first time that these technologies have been used to examine the full course of pregnancy in any animal. It allowed us to examine the genetic basis of the processes going on inside the pregnant pouch.

We found that seahorse pregnancy is incredibly complex: more than 3,000 different genes are involved. When we examined them in detail, we found genes involved in many different processes. We even discovered genes allowing seahorse fathers to provide nutrients to their developing embryos.

But we still haven’t solved the mystery of why seahorse fathers get pregnant given that females have that responsibility in every other animal. Seahorse mums still contribute nutrient-rich egg yolks that feed developing embryos, but their responsibility for their offspring ends at mating.

So seahorses, with their bizarre reproductive strategies, still have plenty more to offer evolutionary biologists.

WATCH THE VID HERE

 - Author: Rachael Bale, ANIMALS executive editor at Nat Geo