As the BBC reported, the first vertebrate cloning ever observed in nature (without researchers' futzing around with the animals' reproductive organs) happened in a captive boa constrictor, who gave birth to not one but two litters of clones from unfertilized eggs, each of which held a recessive mutation that led them to be caramel-colored. The crazy part about this was that mom was not caramel-colored herself, nor were any of the males. Whoa. This led researchers to investigate her babies' DNA, finding that they had indeed not only been created by cloning, but that, in the cloning, had created a new gender. While humans' chromosomes are XX (for female) and XY (for male), snakes' and many other reptiles' chromosomes are different: male snakes are ZZ, and female snakes are ZW (the Z chromosome from the father, the W from the mother). Yet, all of the snakes in these litters were WW, further suggesting they had been produced entirely from two of mama's chromosomes. WW vertebrates had never been observed in the wild before this, and had never survived in lab tests. This was the first vertebrate cloning ever observed in nature, and it was pretty damn cool.