This Week in Sex is a weekly summary of news and research related to sexual behavior, sexuality education, contraception, STIs, and more.
New Evidence Puts Closer Timestamp on Human-Neanderthal Mating
Scientists have long known that modern humans and Neanderthals had some prehistoric trysts because we share genetic material. Now, a 45,000-year-old thigh bone is giving them more information about exactly when those genes may have crossed over.
In 2008, an ivory carver found the thigh bone in question on the banks of the Irtysh River near Ust’-Ishim, Russia in 2008. Since then, an international team of scientists has determined that it was the femur of a man who lived 45,000 years ago. They then mapped the DNA of that man, and found that he had about 2.3 percent Neanderthal genes; modern people of Eurasian descent have from 1.6 to 2.1 percent. The scientists used this mutation rate to work backward in time and estimated that Neanderthals and humans started swapping genes somewhere between 50,000 and 60,000 years ago. Their results are published in a recent issue of the journal Nature.
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Though a 10,000-year “give or take” may seem huge, it is much more precise than previous estimates, which placed the swap somewhere between 37,000 and 86,000 years ago.
Some scientists caution, however, that pinpointing a date may just add to the confusion. John Hawks, a paleoanthropologist at the University of Wisconsin in Madison, told National Geographic that the paper was convincing, but that it is “almost certainly is an oversimplification.”
Hawks continued, “The contacts [between Neanderthals and humans] could have extended over a longer period.” On that point, the authors of the new study seem to agree. Their paper suggests that Neanderthal and humans met again more recently elsewhere in the world, possibly explaining why today’s East Asians have a higher percentage of Neanderthal genes than other modern humans.
Virtual “Autopsy” Says King Tut’s Parents Likely Brother and Sister
In other anthropologic news, an international team of researchers conducted a “virtual autopsy” of King Tutankhamun for an upcoming BBC documentary. They created a life-size image of the ancient Egyptian king using over 2,000 CT scans of his mummified remains. The results reinforce suspected information about King Tut’s parentage and cast doubt on the theory that he died in a chariot crash.
King Tut was born in 1341 B.C. and assumed the throne at the age of 9 or 10. He is believed to have died around the age of 18. He has been a household name since his nearly intact tomb was discovered in 1922, sparking international interest in Ancient Egypt.
This most recent examination of his remains includes suggestions that he had a club foot. This finding likely eliminates the popular possibility that King Tut died in a chariot crash, which had originally been suggested in part because his mummy had an unhealed knee fracture. Gayle Gibson, an Egyptologist who appears in the documentary, told the Huffington Post that his foot would have meant he walked with a cane and likely prevented him from participating in chariot races at all.
A genetic analysis conducted alongside the “virtual autopsy” also reinforces previous suggestions that his parents were brother and sister. Given that consanguinity increases the chance of inherited genetic disorders, this could have also contributed to a heightened likelihood of fractures, or possibly caused King Tut’s early death.
Male Birds Poison Themselves to Be More Appealing to the Ladies
Moving from anthropology to ornithology, another recent article in National Geographic notes that, for the first time, male birds have been found poisoning themselves as a way to look more attractive to potential mates. The article focuses on the Great Bustard, a large bird native to parts of Europe and Asia.
The mating ritual of the Great Bustard is complicated—and, truthfully, just a little gross. During mating season, National Geographic explains, the males “congregate on a patch of ground called a lek and take turns trying to woo females. They contort their bodies to reveal bright white feathers on their chest and rump and suck air into a special throat sac to inflate two bare patches of skin on the neck.”
The point of this, however, is not to show their feathers or their neck; it’s to reveal their cloaca, a single hole that serves reproductive, urinary, and fecal functions for birds. Given its many uses—and the fact that it can be an indicator for disease—it shouldn’t be surprising that female birds want to inspect it carefully before they commit. And they don’t just look at it, they peck at it.
If the male Great Bustard wants to get some, he’s going to have a nice, clean cloaca. Though a bird bath (or a birdie bidet) might do, he instead eats some extra poison. Great Bustards of both sexes eat blister beetles, a bug that contains a toxin called cantharidin. Too many blister beetles will kill them, but just enough will clean out male birds’ intestines and make them appealing to females. An experiment at the National Museum of Natural History in Spain confirmed that males preferred blister beetles to other prey, and that when they chose a beetle for dinner, bigger was better. This was not true of females.
Before any of us attempts to woo a suitor by eating poison (or beetles, for that matter), we should note that the findings are preliminary. Scientists can’t yet prove that this behavior gives the birds any advantage during mating season.