[tsimionescu]

To be fair, you almost always still need two individuals to get reproduction going - you just don't need to be as picky about which two individuals as you might think. There are a rare few animals that can sometimes self-reproduce, but it's not a common strategy in the animal kingdom, even among hermaphroditic animals.

[duskwuff]

They're less rare than you might think. Parthenogenesis ("virgin birth") occasionally occurs in some domestic birds, including chickens and turkeys. Due to the way sex determination works in birds, the offspring created this way are always male.

https://www.sciencedirect.com/science/article/pii/S003257911...

[rsynnott]

There are also a number of species of lizards, and one snake, which reproduce exclusively via parthenogenesis: https://en.wikipedia.org/wiki/Parthenogenesis_in_squamates

In some though not all such species, there are no known male examples _at all_ (though in reptiles some forms of parthenogenesis can produce males).

[dexterdog]

Thank you so much for introducing me to this concept. I knew the word thanks to Shriekback. I used to have ducks. At one point when I only had 3 females, I found a broken egg with a fetus in it. I knew they were all female, but couldn't convince anybody of what I saw.

[dekhn]

Parthenogenesis is not uncommon in animals: https://en.wikipedia.org/wiki/List_of_taxa_that_use_partheno... (I am mostly quibbling with "rare few animals" but I can't really say much about the relative prevalence of parthenogenesis compared to sexual reproduction.