The yellow-bellied watersnake at the Cape Girardeau Conservation Nature Center in Missouri is known to have had no contact with a male snake for at least eight years but this did not prevent her from giving birth.
For the second time in two years, the captive snake has given what is known as "virgin birth." The snake managed to give birth on her own last year and appeared to reproduce this way again this year.
The two snakes that were born last year survived and are in good health but none of the snakes that were born this year was as lucky.
Researchers from the Missouri Department of Conservation believe that the snake is the first in her species to reproduce through virgin birth, a process of asexual reproduction scientifically known as parthenogenesis wherein the female produces babies from unfertilized eggs and without requiring genetic contribution from males.
No other case of parthenogenesis has been observed in a yellow-bellied water snake, which gives birth to live snakes and not eggs.
Although this process of reproduction occurs in insects, some lizards and amphibians and plants, it rarely happens in snakes albeit several snakes have already been observed to have given virgin births including a Burmese python who laid 61 eggs, six of which were found to be fertile.
Researchers believe that because the watersnake in Missouri is in her prime breeding age but do not have access to a male, her body reacted for reproductive survival and changed so she can reproduce on her own.
Although it is possible that the snake has stored sperm from when she was in the wild, experts said that eight year is too long. A female snake cannot usually store sperm for longer than one year albeit there have been cases of successful long -term sperm storage for as long as three years.
"Long-term storage is unusual. When you run into situations like this, you always wonder, 'Is that a possibility?" said Robert Powell, a snake expert from Avila University in Kansas City. "If nothing else, it's an interesting phenomena. Whether this is long-term storage or parthenogenesis, it's cool. Just another sign that nature works in mysterious ways."
Virgin births may be interesting but they are not desirable in terms of evolution because the babies will be near-clones of their mother and this does not go well with genetic diversity.
