A curious incident has occurred in the reptile house of Saint Louis Zoo: a ball python has laid a batch of eggs despite having no contact with a male python for decades. A true strong independent snake.
Saint Louis Zoo in Missouri announced this week that their zookeepers were surprised to find their 65-year-old ball python had laid seven eggs back in July. This was unusual enough, considering the snake was very old, but their curiosity deepened when they worked out the mature female had not been near a male for at 15 years.
Ball pythons (Python regius), also known as Royal pythons, are a species native to the grasslands of central and western Africa. The average ball python lives up to 30 years in captivity, so this individual is exceptionally old, especially for a mother-to-be.
“She’d definitely be the oldest snake we know of in history,” Mark Wanner, manager of herpetology at the zoo, told the Associated Press in reference to laying eggs.
This mysterious batch of eggs is unlikely to be a case of secret lovers in the nighttime when the zookeepers aren’t around. Instead, the zoo says there are two possible explanations.
Firstly, it is possible for ball pythons and some other reptiles to store sperm for delayed fertilization. This is a strategy that allows animals to have offspring at a more convenient time.
Alternatively, the python might have reproduced asexually through a process known as facultative parthenogenesis. Stemming from the Greek words for “virgin birth,” parthenogenesis is a relatively common process in several insect species and plants. It’s also not unheard of among a select handful of vertebrates, including some species of lizards, snakes, rays, sharks, and even birds. This is a natural form of asexual reproduction and an unfertilized egg can grow and develop embryos without fertilization from sperm.
It’s an incredibly useful trick if a female doesn’t come into contact with a male for an extended period, but it’s generally considered to be not as preferable as good old fashioned sexual reproduction because it can lead to a low genetic variation among a population and comes with many risks.
The zoo isn't sure yet which of these possible scenarios is the case, but they hope to find out through DNA testing once the eggs hatch. If the female did produce the eggs asexually without the need for a male, then this is would be clearly shown in their genes.