But from only two teeth and a piece of finger bone smaller than a penny, we've been able to extract the rich history of a species that split off from Homo sapiens approximately 600,000 years ago. We know they're more closely related to Neanderthals than humans—though still distantly. We know they made their way to Southeast Asian islands, interbreeding with indigenous modern human groups in New Guinea and Australia. We know their interspecies mingling with modern humans in mainland Asia was brief, but enough to impart a few genes. And we know Denisovan genes reveal evidence of interbreeding with Neanderthals and an even more ar