Photograph courtesy Institute for Ocean Conservation Science/Matthew D. Potenski
According to National Geographic (http://news.nationalgeographic.com/news/2008/10/081010-shark-virgin-birth-2.html) somehow, against what has always been believed, a female shark was able to fertilize her own egg WITHOUT A MALE SHARK and it was proved by DNA evidence!
This happened at the Virginia Beach Aquarium in Virgina Beach, VA. Why did I choose to write about this? Because it totally proved our normal belief system wrong. Most mammals/fish reproduce by normal sexual reproduction but this particular shark, a Blacktip Shark, is apparently capable of what is called heterogamy, or the use of both sexual and asexual reproduction (http://en.wikipedia.org/wiki/Asexual_Reproduction#Alternation_between_sexual_and_asexual_reproduction). On the wikipedia site, it states, “There are examples of parthenogenesis in the hammerhead and blacktip sharks. In both cases, the sharks had reached sexual maturity in captivity in the absence of males, and in both cases the offspring were shown to be genetically identical to the mothers.” This is what happened to this shark: she was in captivity for many years and when she reached sexual maturity, she had no male to reproduce with so she decided to do it herself (finally a fish that is a feminist). As a person who tends to be of a more feminist opinion, this article was very interesting to me. This event is transcendent in the world of science! An absolute anomaly!
Questions:
Has this ever happened before?
We all know that to create a fertilized child, you need a sperm and an egg. Does every one of these species of sharks (hammerhead and blacktip) have both sperm and egg or is it a freak thing?
2 Responses to “Shark Virgin Birth”
I have never heard of a fish reproducing both sexual and asexually.However after reading that this particular shark was living in captivity, at the Virginia Beach Aquarium in Virgina Beach, VA I decided to look up other documented accounts of strange activity.
I searched Wikipedia “captive animal’s behavior”,scrolled down to the section titled,”Behavior of animals in captivity.” >
http://en.wikipedia.org/wiki/Captivity_(animal)
Animals living in captive conditions,especially non-domesticated ones sometimes develop repetitive, apparently purposeless motor behaviors called stereotypical behaviors.Scientists think that these repetitions are caused by abnormal environments. After I read that I went to another link for Stereotypical Behaviors >
http://en.wikipedia.org/wiki/Stereotypical_behavior
A stereotypy could be recognized in any form of repetitive or ritualistic movement, posture, or utterance.If we were speaking in terms of “sea-life” then some examples could be swimming in circles,obsessive grooming,or pacing. “Stereotypical behaviors are thought to be caused ultimately by artificial environments that do not allow animals to satisfy their normal behavioral needs.”
Does the Black Tip Shark’s in Coverit’s post show signs of stereotypical behavior in the sense that its trying to satisfy it’s normal behavioral needs?
That’s the craziest thing I’ve ever heard! I didn’t even know that possible. This article http://www.nova.edu/ocean/ghri/natgeo_virginshark.html talks about how this happened back in 2001; it was a hammerhead shark. I’ve done some research on this article and In this website http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TCM-4WVCSW8-2&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1051624123&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=a0076b2938b845e284d1f52ec08f8960 it says that female sharks storage fresh sperm, and I think this is the reason why this shark was able to give birth to a shark by herself.