The story unfolded at the LEO Zoological Conservation Center in Greenwich, Conn.: Last month, Armani gave birth to a cute baby pup named Archie. The only problem was, Archie wasn’t supposed to exist.

Armani already had given birth last August to a female pup named Alice, fathered by a male anteater at the center named Alf. Anteater dads have been known to kill off their progeny, so Alf was put in a separate pen for several months. Marcella Leone, the nonprofit center’s founder and director, said Armani and Alf shouldn’t have had the opportunity to conceive little Archie.

“It is our protocol that that should not happen, so it’s a mystery,” Leone told NBC News.