Even if the elephant had recognized itself definitively, the mirror test leaves many unanswered questions about the animal's thought processes, Hauser explains. For example, monkeys have shown signs of self-monitoring on mental tasks even though they fail the mirror test.
The finding should be replicated, agrees Gallup, who created the mark test several decades ago. But the two elephants that failed to recognize the "X" should not diminish Happy's accomplishments, he says. After all, many people fail the mark test, including those with autism and babies younger than 18 months.
If the research does hold up in time, the result would be both surprising and exciting, says Gallup, because elephants don't share a common ancestor with people the way apes do.
"This kind of adaptation may represent a solution to similar problems in unrelated groups," he says. "This would represent a striking instance of convergent evolution."