Pregnant males- Life of seahorses

 Pregnant males- Life of seahorses

- Haripriya J

Don’t you think that we are blessed to be born on the earth? Have you ever seen an ant that struggles to carry a small piece of cake? Have you ever thought what are the strategies that a mosquito makes just to suck your blood? A small puppy at your home wages its tale so that you can feed him and show him love. Have you seen while cattle grazing, few birds will be around the cattle? Why so? Sometimes I feel we know very little; we have seen very less.

While I was reading a book of Nemichandra which was about great women scientists, I came across a great scientist named Dr. Amanda Vincent, she was the one who studied the lifestyle of sea horse. There I came across a surprising note that Male sea horse get pregnant. We always upheld the sacrifices of our mother who gave us birth. The care she shown to us, she is the one who always stand for us. We sometimes feel bad about the patriarchal society. And we generalize things easily and deny the care and support given by the father. But here a tiny male creature is leading mother’s role of giving birth to their young ones!

How do seahorses differ from all other animals?

I was mesmerized when I read about the lifestyle of Sea horses. For their lifetime, female sea horse mate only with one male sea horse and vice-versa! Everyday Female sea horse meets her partner and after mating she returns. While returning even many male sea horses come across her way, she never bothers about them. They lead their entire life with one partner only. Is it not shocking? When human have trust issues with their life partners how a tiny fish can lead its whole life with only one partner?

Seahorses and their close relatives, sea dragons are the only species in which the male gets pregnant and gives birth. Many researches have done research related to this. I would like to share some points.

Seahorses are members of the pipefish (narrow, elongated, chiefly marine fish with segmented bony armor beneath the skin and a long, tubular snout) family. In addition to their iconic appearance, seahorses possess many interesting attributes. Among them are specialized structures in their skin cells, called chromatophores, which allow the mostly sessile (permanently attached; not freely moving) seahorses to change color to mimic their surroundings. Well

camouflaged as they cling to stalks of seagrass in their shallow habitats, seahorses can be hard to see.

Their truly remarkable biological claim to fame, however, is that male seahorses and sea dragons get pregnant and bear young—a unique adaptation in the animal kingdom.

When it comes to gender stereotypes, seahorses and their relatives would have to be one of the most extreme examples. These fish swap the traditional roles of moms and dads as they are the only animals where the males get pregnant. Even though fish don’t have the external genitalia that we normally associate with males and females, we can still distinguish between them. That’s because we classify animal sexes according to the size of the gametes (sex cells) they produce. Males produce the sperm (the smallest gametes) and females produce the eggs (the biggest gametes).

But in seahorses, 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 fertilize the eggs as they enter, before incubating them for 24 days until they are born.

In research published in Molecular Biology and Evolution, just in time for Father’s Day, a team investigated whether male seahorses contribute more to their offspring than just sperm. They 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 them to examine the genetic basis of the processes going on inside the pregnant pouch

They found that seahorse pregnancy is incredibly complex: more than 3,000 different genes are involved. When they examined them in detail, they found genes involved in many different processes. They even discovered genes allowing seahorse fathers to provide nutrients to their developing embryos. Fathers supply energy-rich fats and calcium to allow the embryos to build

their tiny skeletons and bony body rings that sit just under the skin. Other pouch genes help the males remove wastes produced by the embryo, such as carbon dioxide and nitrogen.

Seahorse dads even seem to protect embryos from infection, producing antibacterial and antifungal molecules to ward off pathogens. Seahorse birth is even more of a mystery than seahorse pregnancy, and they were excited to find that some of those 3,000 genes also prepare the father and the embryos for labor. With around one week to go, instead of packing a hospital go-bag, seahorse dads start producing hatching signals.

These signals cause the embryos to hatch out from their thin membranes and swim freely inside the brood pouch. As the embryos take up more room, the pouch begins to stretch, much like the belly of a very pregnant human. The hormone estrogen also gets involved and these combined forces produce cascading genetic signals that produce birth.

So, seahorse dads make excellent “moms”, performing many of the same functions that occur in females during mammalian pregnancy and birth. Strikingly, many of the seahorse genes are like those in other pregnant animals. This is surprising because pregnant mammals, reptiles and other fish all incubate their embryos inside the female reproductive tract. Their pregnancies have evolved entirely independently of seahorse pregnancy, millions of years apart, and yet we see the same.

Why would the genes controlling male and female pregnancies be similar? We think that this is because gestation presents the same set of complex challenges to the parent, regardless of species.

Seahorse dads, just like human moms, need to make sure they can provide oxygen and nutrients to their embryos. We do it with a placenta inside a uterus and seahorse dads do it with thickened skin inside a pouch, but we’ve used similar genetic instructions to get there. findings raise the possibility that the same genes have been repeatedly and independently recruited for pregnancy across vertebrate animals – a remarkable display of convergent evolution.

Researchers have shown how seahorse dads use thousands of genes working in concert to provide the ideal environment for embryonic growth. This is a breakthrough in the understanding of the genetics of seahorse reproduction, although much follow up work is required to definitively test the functions of every one of those genes.

Researchers says still they haven’t solved the mystery of why seahorse fathers get pregnant given that females have that responsibility in every other animal. Seahorse moms 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.

See, how strange and beautiful the nature is. A research says, we haven’t explored 50% of Amazon forest, there are lakhs of unknown strange species on the earth which we are still unaware of. Now, you should agree with me that we know very less about our surroundings and least about our earth. Let’s explore the world, love the animal kingdom just open your eyes(mind) and you will see an amazing world around which makes you feel awesome.

Reference:

https://www.youtube.com/watch?v=WKYk6GPuMeI

The secret sex life and pregnancy of sea horse by Camilla Whittington 

Kaalu Haadiya kolminchugalu- Nemichandra