This Lady Shark Got Tired of Waiting for a Dude, Had Babies All by Herself
In a wild turn of events straight out of Jurassic Park, a female zebra shark in captivity just got pregnant and had babies all by herself.
According to CNN, a female zebra shark named Leonie lives at an aquarium in Australia. She was previously housed with a male zebra shark, with whom she had several litters of baby sharks, but three years ago she was put into a girls-only tank with one of her daughters, because the aquarium wanted to stop breeding so many zebra sharks.
Leonie appears to have been of a different mind, because she started laying eggs anyway. The egg-laying is not weird in and of itself, because female sharks in good living conditions will lay eggs even if there’s not a male around. The weird thing is that some of those eggs had little shark embryos in them. They didn’t hatch, though.
Last year, Leonie and her daughter laid eggs again, and this time they did hatch. Leonie had three new babies, and her daughter had two. Neither had been near a male shark in years.
The news was so cool that researchers in the aquarium are not even mad about having five new zebra sharks they weren’t planning on, and they set to work trying to figure out how they wound up with the “virgin birth” sharks.
There were a couple possible explanations. Sharks do occasionally store sperm from one sexual encounter for later, and they thought Leonie was maybe still holding onto some sperm from her old mate. The other option was asexual reproduction, which scientists say they haven’t seen from sharks that had previously reproduced sexually. Some sharks can reproduce asexually if necessary, but scientists say they’d never seen an individual shark just switch from sexual reproduction to asexual reproduction so quickly.
The scientists figured that the stored-sperm theory was more likely, but when they looked at baby sharks’ cellular makeups, they discovered that the babies had a less diverse genetic makeup, which indicated that they had most likely been conceived asexually and had just one biological parent instead of two.
(Cute baby zebra shark pictures via Wikimedia Commons)
Being conceived with just one parent means that the baby sharks have a comparatively limited genetic diversity and are more likely to have problems or genetic abnormalities. Still, the scientists are very pleased with their miracle shark babies, and are looking forward to seeing if they can reproduce sexually when they get bigger.