A female Komodo dragon named Charlie who lives at the Chattanooga Zoo had three hatchlings without ever having mated. Charlie's hatchlings were born last year but the zoo only recently determined via DNA testing that a male named Kadal who shared her habitat wasn't the father. Indeed, there was no father. Komodo dragons are capable of parthenogenesis, asexual reproduction that's very rare in vertebrates. From CNN:
Komodo dragons have evolved to reproduce both sexually and parthenogenetically because they mainly live isolated in the wild and become violent when approached, according to the zoo.
Parthenogenesis happens when another egg, rather than sperm, fertilizes an egg, according to Scientific American. The biological process of making an egg cell, called oogenesis, typically produces a polar body, which contains a duplicate copy of egg DNA.
"Normally, this polar body shrivels up and disappears. In the case of the Komodos, though, polar bodies evidently acted as sperm and turned ova into embryos," Scientific American said in 2006 when the first cases of parthenogenesis in Komodo dragons were reported.