Male Pregnancy1 in the animal kingdom. It sounds contradicting right? Not.
The female species are the ones that carry the fetuses until their birth, in almost entirely the heterogamous2 animals.
But there is an exception. Or maybe more, if we wish to be precise.
Scientists have observed that there are species that perform role reversals, this can be a natural procedure or a procedure occurring after chemicals' affects.
We will discuss about:
- Sex Transformation after Exposure to chemical substances3
- Natural Male Pregnancy
In this post we will mainly present the reproduction procedure for seahorses, but think appropriate to include information for further reading and most importantly for raising awareness regarding chemical’s consequences in our nature.
Male frogs can lay eggs as an impact of pesticides effects
As per a study published in 20104, a herbicide named atrazine has affected amphibians and has revealed reproductive alterations.
More specifically, the male African clawed frogs (Xenopus laevis) that were exposed to Atrazine were both demasculized and also feminized
As a matter of fact, 10 per cent of the exposed males developed into functional females that produced viable eggs after their copulation with males.
This study is presented and we will not analyze it more. If someone wishes to research about it, they can visit this page by the University of Hertfordshire for further reading. Please keep in mind that this herbicide does not have EU approval.
Seahorse by Kristina D.C. Hoeppner – flickr CC BY – SA 2.0
Sea Horses: Unparalleled mating behavior.
In fish that belong to the Sygnathidae family, species such as pipefish, seahorses and the leafy sea dragon; the reproduction occurs by male pregnancy. Let’s find out how this complex procedure takes place.
Flirting & Mating Behaviour
The courtship of the seahorses may have a duration of several days. During their ‘flirting period’ the seahorses may change their color, dance side by side while they are holding hand in hand (tail to tail) and perform a ritual named ‘predawn dance’
Their dance can last up to 8 hours and it is impressive that during that time, the male actually shows his belly (egg pouch) by pumping water through it.
When the female’s eggs are mature, the next phase begins. They usually spiral as they grasp each other,
Seahorse Mating Dance, filmed at Seahorse Aquariums in Dublin.
Afterwards the female will squirt her eggs into the male’s pouch and then she swims off and lets the male by himself.
Gestation
The male will remain pregnant from 10 days to 3 weeks (depending on the species), during which the female visits him every day in a what you would call ‘romantic behaviour’ where they interact with each other, holding tail by tail and at times change colour.
It has been observed that the male seahorses stick to a very small area of their habitat (approximately one square meter) while the females can range in areas far wider ones.
The body of the male seahorse provides oxygen, nourishment to the embryos, calcium for their skeletal system and immunological protection in a safe ‘incubator home’ for the baby seahorses until they are born.
Birth and Newborn Care
The male horses undergoes muscular contractions5 during the birth of the little ones. This is known as ‘fry’.
Males of some species give birth to a few dozen, but others bear more than 100, and one Caribbean male astonished researchers as his half-tablespoon pouch held more than 1,500 babies.
After their birth, the tiny seahorses should take care of themselves immediately, feed themselves and stay away from predators. It has been calculated that 5/1000 infant seahorses can survive to their adult hood. Nevertheless this is considered a higher percentage of success than the fish’ eggs, because during their hatching, the seahorse eggs are safely kept in the pouch of their dad (in opposition with fish eggs which are scattered in the sea)
The seahorses' ‘love and sex life’ is the subject of various researches; the scientists perform a variety of experiments and observe their behavior, in order to track and understand the evolutionary steps that led the unique shape and behavior of this species.
Biology researcher Adam Jones from the Texas A&M University states
"Ultimately, we hope to gain deeper insights into some of the evolutionary mechanisms responsible for the incredible changes in the structure of organisms that have occurred during the history of life on Earth."
And if this mating dance does not put you in the mood for tomorrows Valentine Day, I really do not know what will!
Thank you very much for visiting : )
Sources and further reading >
[1] – Male Pregnancy – Wikipedia
[2] – Heterogamy – Wikipedia
[3] – News.NationalGeographic.com
[4] – US National Library of Medicine
[5] – National Geographic News
[6] – Science Daily
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