> (even assuming we know we're just talking about earth)
This is a nitpick, but life on other planets wouldn't be called “animals”. Animal is a clade defined by common ancestry. The only way you could have an extraterrestrial animal is for it to have evolved on Earth and then migrated somehow, and I think we can fairly confidently rule that out.
This is a nitpick, but life on other planets wouldn't be called “animals”. Animal is a clade defined by common ancestry. The only way you could have an extraterrestrial animal is for it to have evolved on Earth and then migrated somehow, and I think we can fairly confidently rule that out.