As an endemic species found only in Indonesia, have you ever wondered how Komodo dragons have managed to survive to this day?

In fact, the Komodo dragon's survival is unique. They are able to continue to reproduce even when there are no males in the population. This phenomenon is made possible because female Komodo dragons can produce offspring without the need for fertilization by a male.

This phenomenon is known as parthenogenesis, a unique reproductive process that allows female Komodo dragons to produce offspring without the involvement of a male.

The term parthenogenesis, derived from the Greek meaning "virgin birth," was first used by the Swiss naturalist Charles Bonnet in the mid-18th century. Initially, this process was thought to be limited to plants, insects, and other invertebrates, where parthenogenesis is a relatively common phenomenon.

However, recent biological research has shown that similar processes occur in fish, reptiles, birds, and even mammals.

Parthenogenesis offers several extraordinary mechanisms in the world of reproduction. For some species, it serves as an emergency alternative when mates are hard to find; for others, it becomes the only means of continuing the lineage; and for still others, it is used flexibly depending on their ecological needs.

In the case of the Komodo dragon, the ability to reproduce both sexually and through parthenogenesis is thought to have evolved as a response to its isolated habitat in the Indonesian archipelago. Similar phenomena have been observed in other species, such as dragonflies in the Azores, which adopt parthenogenesis when faced with a limited number of mates.

Researchers speculate that this adaptation may allow female Komodo dragons to establish new populations when stranded alone on a remote island, such as after being swept away by a large storm.

Read also: Why Komodo Dragons Only Exist in Indonesia?

Another Twist: The Reverse Sex Determination of Komodo Dragons

In addition to their ability to lay eggs without the help of a male, Komodo dragons also have a very unique sex determination system. Unlike mammals, where females have XX chromosomes and males have XY chromosomes, Komodo dragons follow the opposite rule. Their sex chromosomes are labeled W and Z, with the ZZ combination producing males and the WZ combination producing females.

In female Komodo dragons, each egg carries either a W or a Z sex chromosome. During parthenogenesis, the resulting embryo will have either WW or ZZ chromosomes. Eggs with the WW combination cannot survive and will die, similar to the YY combination in humans. However, embryos with the ZZ combination can survive, meaning that all offspring produced by parthenogenesis are male.

The uniqueness of this process lies in the duplication of genes during egg formation (oogenesis), where a small cell called the polar body - normally a copy of the egg's DNA - shrinks and disappears. In Komodo dragons, however, this polar body acts like sperm, fusing with the egg and triggering the formation of the embryo.

Read also: The Iron-Coated Teeth of Komodo Dragons: A Modern-Day T. rex

First Discovery

In 2006, two zoos in the UK were surprised when female Komodo dragons gave birth without ever interacting with a male. One even demonstrated the ability to switch to sexual reproduction after being paired with a male. 

This revealed the extraordinary flexibility of the world's largest reptiles, able to adapt their reproductive methods - both sexual and asexual - to their needs.

"Parthenogenesis has never been recorded in Komodo dragons, so this is truly a world-first discovery," said Kevin Buley, a researcher at Chester Zoo. In many zoos, female Komodo dragons often live in isolation from other individuals, and this adaptation allows them to continue reproducing even under restricted conditions.

Unique Reproduction: A Double-Edged Sword

This unique adaptation plays a critical role for the Komodo dragon population, which lives in an isolated environment where finding a mate is often a challenge. Whether through mating or parthenogenesis, females can produce approximately 20 eggs in a single reproductive cycle.

This reproductive strategy may serve as a temporary lifeline for the Komodo dragon, a critically endangered species with only about 1,000 adult individuals remaining in the wild. In critical situations, the ability to reproduce without a male may help sustain the population.

However, this strategy has significant limitations: due to the unique nature of their chromosomes, parthenogenesis only produces male offspring that cannot continue the asexual reproductive cycle in the next generation.

In the long run, this approach risks causing health problems due to inbreeding. Similar to the tragic story of Oedipus, low genetic diversity within the colony can weaken the species' ability to withstand environmental challenges and disease, limiting the effectiveness of this strategy as a long-term solution for sustainability.