I have a few and have had more in the past, but my current most interesting I think are mourning geckos. They're a little gecko and when they were found in the rainforest the researchers realised they were all female, so assumed some dreadful disease had killed off all the males and called them 'mourning geckos' as they were mourning all their husbands and would die alone.

Turns out nope, they don't need men, they're independent women, they lay fertile eggs through parthenogenesis, who are also female.