Self-impregnated snake in Missouri has another 'virgin birth'

CAPE GIRARDEAU, Mo., Sept. 21 (UPI) -- For the second summer in a row, a little water snake in Missouri has gotten herself pregnant.

This time, none of the "virgin births" survived, but two snakes from her last go at it are alive and well.

The yellow-bellied water snake lives inside an enclosure at the Cape Girardeau Conservation Nature Center. She hasn't had contact with any male snakes for several years. Yet, once again, her caretakers found her cage filled with snake eggs.

"I thought, 'what joker put tomatoes in here for the snake,'" intern Kyle Morton recalled in a press release.

Yellow-bellied water snakes typically have live births.

The scientific terms for the so-called virgin births is parthenogenesis -- the production of unfertilized eggs. It's relatively common among insects, but relatively rare in reptiles, birds and fish. The strategy isn't employed by mammals.

"There are many types of parthenogenesis," explained Jeff Briggler, the center's herpetologist. "In layman's terms, parthenogenesis is a mode of asexual reproduction in which the offspring (babies) are produced by females without genetic contribution of a male."

While it may possible to "have it all," this empowered mother's reproductive method doesn't come without risks. It's likely defective chromosome combining are to blame for failure of this summer's eggs.

"There is always a high proportion of infertile eggs due to chromosome combination, but a few can be successful and hatch if the mother has a dissimilar sex chromosome (ZW) compared to the male with copies of the ZZ chromosome," Briggler said.