'Virgin Births' in animals: AKA asexual reproduction!

Today’s article is not going to only be about birds!

In a previous article, we learnt about the miraculous ‘virgin births’ in the endangered California Condor.

Image credit: The Washington Post. In 2021, US wildlife researchers were absolutely blown-away when they discovered that two California Condors gave birth without any male genetic DNA.

In rare bird species, any birth is a miracle in itself. But a virgin birth - aka a clone of the mother - is extra miraculous!

This act is colloquially called virgin birth, but in the world of science, it’s called parthenogenesis or asexual reproduction.

Today, let’s learn about the animals that give Mother Mary a run for her money!

1) Reticulated Pythons are one of the few vertebrates that can have “virgin births,” made possible by parthenogenesis.

The Reticulated Python in question is one named Thelma, who lives in the Louisville Zoo in Kentucky. Interestingly enough, Miss Thelma had not even laid eyes on a male python for years! Yet, one fine day in 2012, zookeepers were stunned to discover a clutch of eggs that came from Thelma - six of which eventually hatched, and developed into healthy young snakes.

For years, Thelma had lived only with another female python called Louise. In the summer of 2012, Thelma laid a huge clutch of 61 eggs, which she covered and kept warm for weeks.

Image credit: Thai National Parks. The reticulated python is a python species native to South and Southeast Asia. It is the world's longest snake, and is among the three heaviest - they can weigh up to 75kg!

Because it isn’t uncommon for a snake to lay unfertilised eggs, staff let it be for a while. But upon closer inspection, they were absolutely gobsmacked to find Thelma’s eggs looking full and healthy, instead of shrunken and discoloured - which is how unfertilised eggs usually appear.

Image credit: Discovery Place. Unfertilised snake eggs are called slugs and are normally smaller and yellower than fertilized eggs. Unlike bird eggs, which have a hard outer shell, snake eggs feel soft and leathery.

Thus, a decision was made to artificially incubate some of the eggs to ascertain whether they were fertile - and around three months later, six out of 61 eggs hatched!

To confirm whether Thelma's offspring were born via parthenogenesis, shed skins from her and her offspring were sent to the University of Tulsa’s molecular ecology laboratory in Oklahoma. The results were in - Thelma was a virgin goddess among snakes!

Wait! What exactly is parthenogenesis, or ‘virgin birth’?

Parthenogenesis comes from two Greek roots that literally translate to “virgin creation.”

The Parthenon, in Athens of Greece, is a temple of the virgin goddess Athena.

Parthenogenesis is an extremely rare event among animals. It happens when a cell in a female behaves like a sperm, and fuses with an egg.

Among smaller animals, mostly invertebrates, it’s relatively common: it’s been recorded in water fleas, rotifers, aphids, stick insects, some ants, bees and parasitic wasps and more.

However, among vertebrates, it’s a little more rare. Vertebrates are animals that have an inner skeleton - the Reticulated Python, as well as all other snake species, fall into this category.

More fun facts about Reticulated Pythons:

They live in South East Asia (where Singapore is, and where I live!) and like all pythons, are nonvenomous constrictors. They are excellent swimmers!

The snakes eat mammals such as pigs, rats and goats, and will eat birds (if they can catch them!) These snakes are famous for their huge jaws and appetite, and and can swallow prey up to a quarter of their own length and as heavy as themselves.

Image credit: U.S Geological Survey

They are ambush hunters and wait until prey wanders within strike range, before seizing it in their coils and squeezing it to death. While they are strong enough to kill a grown man, this is very rare. Recently, though, a woman’s body was found in a python’s body. Though such incidents are rare, this is not the first time someone in Indonesia has been killed and eaten by a python. Two similar deaths were reported in the country between 2017 and 2018.

Female Reticulated Pythons usually lay between 15 and 80 eggs per clutch, which take an average of 88 days to hatch.

What other animals can give birth virginally?

Here’s a list of a few other vertebrates that have reproduced via parthenogenesis:

1. Komodo Dragons

2. Zebra Sharks (just like Thelma, a certain female shark named Leonie was housed with females and shocked her keepers when her eggs produced healthy shark pups!)

3. Blacktip Sharks

4. Mole Salamanders

And so much more!

For millions of years animals have reproduced via parthenogenesis, which first emerged in some of the smallest, simplest organisms.

But for more advanced animals like vertebrates, scientists think that the ability to reproduce asexually came about as a last-ditch effort for species facing adverse conditions.

That may explain why parthenogenesis is possible in so many desert and island species - such as the Desert Grassland Whiptail Lizard, which lives in the desert, and Komodo Dragons, which can sometimes find themselves marooned on uninhabited islands, without a mate in sight.

Image credit: Journal of a Naturalist. The desert grassland whiptail lizard is an all-female species of reptiles in North America. Desert whiptails reproduce by parthenogenesis: there is no sexual reproduction because this species contains only females!

Parthenogenesis has been observed in more than 80 vertebrate species, about half of which are fish or lizards. It’s extremely rare that complex vertebrates such as birds, sharks, snakes, and large lizards rely on asexual reproduction, which is why Thelma (the snake) and Leonie (the shark) initially stumped scientists.

Image credit: Awesome Ocean. Leonie is a Zebra Shark that recently gave birth to three pups via asexual reproduction at the Reef HQ Aquarium in Townsville, Australia.

In some very rare cases, animal species reproduce via parthenogenesis exclusively.

One such species is the Desert Grassland Whiptail Lizard, all of which are born, and live as, female!

This species can be found in the desert grasslands of the southwestern United States and northern Mexico.

These ladies never, ever have sex and instead, reproduce through a process called meiosis, which is a form of cell division. But because all of the chromosomes come from the mother, all of her offspring are clones!!!

However, because every individual would be genetically identical, Desert Grassland Whiptail Lizard mothers and their daughters would be more vulnerable to disease and environmental changes than a genetically-varied group. In areas of New Mexico, for example, some populations of female Desert Grassland Whiptail Lizard share nearly-identical genetic profiles.

Image credit: The Verge

That means if one bad flu season rips through the family, almost everyone could die…

Virginal vs. vaginal birth - which is superior?

That’s all for today. I hope you had fun reading this article, and that you learnt a BUNCH of new fun facts! Please like and share my post if it taught you something new!