Representational image. A female zebra shark in Chicago gave birth to two pups with a male partner (Pic. Courtesy Twitter/ @SharkiesOTD)
With the year coming to an end the scientists at the Shedd Aquarium in United States’ Chicago city were in for a shock. One of their female zebra sharks had produced pups – two — and that too without mating with a male fish!
Named Bubbles, this female shark shares her tank with many other adult ones and in the beginning, it was assumed that one of the male fish had fathered these pups.
When genetic testing of the pups was done – mandatory as part of the breeding programme of the species – the researchers were astonished on realising that Bubbles had brought them on her own. This is called parthenogenesis or virgin birth in which the female of the species fertilises her own genetic material.
The sharks have been breeding since 2004 and have produced more than offspring so far and this is the first instance of virgin birth.
While zebra sharks are known to reproduce asexually, such occasions are rare and it is believed to be in response to lack of available male mates.
In a Press statement released by the Shedd Aquarium, Kevin Feldhim, who is a researcher at Chicago’s Field Museum said: “This discovery throws a wrench in what we thought we knew about how and why parthenogenesis happens, and it illustrates a key aspect of science: we’re continually learning.”
In a video he said that as the survival rate of pups by parthenogenesis is very low it is a cause of concern. Incidentally, Bubbles, pups did not make it.
The study on this, co-authored by Feldhim, has been published in the Journal of Fish Biology.