Slide 1 of 19
Birds and the bees
Forget what you know about the birds and the bees: Sometimes you just have to take matters into your own hands.
Reproduction typically requires sperm from a male to fertilize a woman's egg, but in some cases, nature has outsmarted the system. To cope with living in captivity, or a lack of suitable mates, evolutionary adaptations have enabled some creatures to have babies without sex. And while that may sound miraculous, it's not as uncommon as you may think. Here are nine incredible tales of virgin births in the animal kingdom.
Zebra sharkSlide 2 of 19
In April 2016, three baby zebra sharks were born at the Reef HQ Aquarium in Townsville, Australia. While the birth of baby animals is not altogether unusual at aquariums, these babies were born to a female shark named Leonie who had been living apart from male sharks for several years. In fact, Leonie was separated from her mate in 2012.
So what gives? At the time, biologists said Leonie could be the first shark ever observed to make the switch from sexual to asexual reproduction. The type of asexual reproduction characterized in Leonie's case is known as parthenogenesis, which occurs when embryos develop and mature without fertilization by a male's sperm. Instead, an egg progenitor cell functions as a surrogate sperm to "fertilize" the egg.
In a study published in January 2017 in the journal Scientific Reports, researchers said Leonie's case suggests that parthenogenesis could be an evolutionary adaptation to a lack of suitable mates. [Read the full story about Leonie the shark]Slide 3 of 19
Yellow-bellied water snakeSlide 4 of 19
Yellow-bellied water snake
Turns out, there's at least one yellow-bellied water snake that doesn't need a man. In September 2015, a female water snake at the Missouri Department of Conservation's (MDC) Cape Girardeau Conservation Nature Center gave birth to a litter of snakes without any help from a male. At the time, the snake had not been with a male mate in eight years, and it was actually the second year in a row that she had a "virgin birth," according to MDC officials.
The female snake's impressive feat boils down to parthenogenesis, during which babies are produced by females absent of genetic contribution from a male. Scientists have seen this type of reproduction in other snake species, including copperheads, green anacondas and pit vipers.
With parthenogenesis, the normal division of cells typically results in four egg-progenitor cells, but instead of the female's body reabsorbing three egg-progenitor cells (leaving one egg), one of the female cells behaves like sperm and fertilizes the egg. Why does this happen? Essentially, this type of asexual reproduction occurs when there is a lack of suitable mates. It's evolution in action, folks. [Read the full story about the snake's virgin birth]Slide 5 of 19
Komodo dragonSlide 6 of 19
At London's Chester Zoo, a female Komodo dragon named Flora had the world's first documented virgin births of this lizard species in 2006. The reproductive process, called parthenogenesis, occurs when an unfertilized egg develops to maturity. In May 2006, Flora laid 25 eggs, including 11 that were viable. Zookeepers knew something strange was going on, because Flora had never come in contact with a male Komodo dragon while at the Chester Zoo. A paternity test confirmed that all the genetic material in the eggs had come from Flora. [Read the full story about Flora's virgin conception]Slide 7 of 19
Boa constrictorSlide 8 of 19