Lilith
09-22-2002, 11:31 PM
Zoo staff stunned by shark’s ‘virgin births’
HOLY mackerel! A female shark at Detroit’s Belle Isle Aquarium that has had no contact with a male for the past six years has produced three babies in what zoo officials are calling "virgin births".
The first two offspring hatched in July and the third was born this week, Doug Sweet, curator of fishes at the aquarium, said in an interview yesterday.
The female trio and their 2ft-long mother, a white spotted bamboo shark common to waters in the South Pacific, are all doing well. Furthermore, a fourth offspring is expected in another couple of weeks, Mr Sweet reported.
"With fish, amphibians and reptiles it does happen sometimes, it is kind of rare but it can happen," Mr Sweet said of the unusual hatchings.
He said they were thought to be the result of a process called parthenogenesis, which is the ability of unfertilised eggs to develop into embryos without sperm.
"The other option here is that perhaps there’s a chance that the female might be a self-fertilising hermaphrodite.
"That is, she might have testicular tissue inside her as well as ovarian tissue, and it’s possible she could be fertilising her own eggs.
"Either way you look at it it’s pretty weird," Mr Sweet admitted.
He said the only other adult bamboo shark in the 680-gallon tank where mother is held is also a female.
"There’s no male around and there hasn’t been any male around for as long as we’ve had the sharks, and we’ve had them for over six years," Mr Sweet said.
Although the births in Detroit were thought to be extremely rare, Mr Sweet said a bonnethead shark, also held without any male companion, had also produced offspring.
It reproduced in late 2001 at a zoo in Omaha, Nebraska.
Unlike with the biblical Immaculate Conception, "In nature, during parthenogenesis, it typically is always a female that is produced," Mr Sweet explained.
HOLY mackerel! A female shark at Detroit’s Belle Isle Aquarium that has had no contact with a male for the past six years has produced three babies in what zoo officials are calling "virgin births".
The first two offspring hatched in July and the third was born this week, Doug Sweet, curator of fishes at the aquarium, said in an interview yesterday.
The female trio and their 2ft-long mother, a white spotted bamboo shark common to waters in the South Pacific, are all doing well. Furthermore, a fourth offspring is expected in another couple of weeks, Mr Sweet reported.
"With fish, amphibians and reptiles it does happen sometimes, it is kind of rare but it can happen," Mr Sweet said of the unusual hatchings.
He said they were thought to be the result of a process called parthenogenesis, which is the ability of unfertilised eggs to develop into embryos without sperm.
"The other option here is that perhaps there’s a chance that the female might be a self-fertilising hermaphrodite.
"That is, she might have testicular tissue inside her as well as ovarian tissue, and it’s possible she could be fertilising her own eggs.
"Either way you look at it it’s pretty weird," Mr Sweet admitted.
He said the only other adult bamboo shark in the 680-gallon tank where mother is held is also a female.
"There’s no male around and there hasn’t been any male around for as long as we’ve had the sharks, and we’ve had them for over six years," Mr Sweet said.
Although the births in Detroit were thought to be extremely rare, Mr Sweet said a bonnethead shark, also held without any male companion, had also produced offspring.
It reproduced in late 2001 at a zoo in Omaha, Nebraska.
Unlike with the biblical Immaculate Conception, "In nature, during parthenogenesis, it typically is always a female that is produced," Mr Sweet explained.