This post was originally published on January 25, 2013 on a previous version of ChipWalter.com.

Right around the time Last Ape Standing was published in January of 2013 the Internet was all a twitter when Harvard molecular biologist George Church was quoted in Der Spiegel as having said eventually an “adventurous female human” will be needed to act as a surrogate mother for the first Neanderthal baby thanks to anticipated  advances in genetic engineering. He also speculated that from many individuals “a kind of Neanderthal culture” might arise.

Shades of Jurassic Park.

This only underscores how rapidly our view of our past and the effects it may have on our future are changing. Just a few years ago human evolution was seen as a nice steady climb up the Darwinian ladder from hunched primate to upright walking Homo sapiens (we’ve all seen the iconic image), something like an assembly line that delivered a shiny, modern human at the end of the process. That turns out to be all wrong. Not only wasn’t there a solitary line of proto-humans from whom we, and we alone, evolved, but there were multiple species of humans with a wide range of pedigrees roaming Africa’s savannas going back millions of years (27 by the current count). We know this because in the past few years there have been a string of discoveries about our past that have rocked the world of human evolution and completely rearranged our view of who we are and how we got here. Here’s a rundown…

The Hobbits

The first of these discoveries came in 2003 when archeologists found that a Lilliputian species of human, but not a modern Homo sapiens, had been living on the Indonesian Island of Flores as recently as 13,000 years ago. They were dubbed Homo floresiensis, or the “hobbit.” That a creature that could hunt, controlled fire, may have spoken some kind of language, all with a brain as diminutive as a chimpanzee’s flummoxed paleoanthropologists, and excited them too. They didn’t know what to make of them.  The consensus these days is that they evolved from Homo erectus, an earlier branch of humans that had migrated to the Pacific as long as a million years ago, and was thought to have long departed the planet tens of thousands of years earlier.

Want to Date a Neanderthal?

A second big discovery came in 2010 when anthropogists at the Max Planck Institute completed a second review of the Neanderthal genome. They were checking for evidence that Neanderthals and our director ancestors, the Cro-Magnon people–Homo sapiens–who had migrated into Europe beginning 50,000 or so years ago–had mated. Given what happens in bars and boudoirs throughout the world on your typical weekend, it would seem that mating between two humans even if they weren’t the same species would be a no-brainer, but science had long struggled with the idea that separate species would or could mate. The genomic review proved that love, or lust, had won out. Based on the sources of the genetic information supplied, the resolute scientists at Max Planck found that most of the human race with roots from Europe to the islands of Southeast Asia have at least a little Neanderthal running through their veins. A separate test later revealed that aging rock star Ozzie Osborne was also carrying around Neanderthal genes in his DNA, but the world didn’t seem much surprised by that. In any case another foundation of old thinking had been rocked: interspecies sex, once an heretical thought, was a reality. That raised another question: if Neandethals and Cro-Magnon people had done the dirty, had other species too?

Denisovans: Staying Warm in Siberia

The answer to that question came not long afterwards in 2011 when the scientific team at Max Planck once again pulled off another remarkable scientific feat. Working with nothing more than a finger bone fragment from a juvenile girl, the team managed to ascertain the fossil belonged to an entirely new species of human, neither Homo sapiens, Hobbit nor Neanderthal, but a people who walked the earth as recently as 40,000 years ago that scientists unofficially dubbed Denisovans. Not only that, but based on other fossils and detritus unearthed in the cave, it appears the Denisovans hobnobbed with both Siberian Neanderthals and wayward Homo sapiens. The real surprise, however, came when the examination of the Denisovan DNA also revealed that they had mated with both Neanderthals and our direct ancestors. Chalk up “2” for interspecies breeding.

By the way, we really have no idea what the Denisovans looked like because we have no physical evidence of their existence except for the finger-bone, and later separate finds that included a tooth and toe bone. Scientists are still looking for more fossils.

Red Deer Cave People: The Newest Addition to the Human Family

You would think all of this would be plenty to keep paleoanthropologists busy for years, and it will, of course. Nevertheless, another shattering discovery surfaced in March 2012 when scientists in Australia and China put together the broken skull bones of several creatures found in two different cave locations in southern China. The odd thing about the specimens was they combined archaic human features with modern ones, and they belonged to a species that had been living in the region as recently as 11,500 years ago, just as Homo spaiens were on the verge of making one of the most important advances in human history– agriculture.

This easily made them the most recent species to co-exist with our direct ancestors; three millennia closer than the last known Hobbit and a good 14,000 years closer than the Neanderthal. But not everyone agrees that the Red Deer Cave People (temporarily named for where they lived and the animal they hunted) are a separate human species. They could be, or they could be a hybrid result of interspecies breeding among Denisovans and nearby Homo sapiens, or even descended from a combination of Denisovans and Homo erectus. It’s simply too early to tell, but the Max Planck team is busy analyzing the DNA right now. More will almost certainly be forthcoming.