New bone evidence suggests that Tyrannosaurus rex was not only a scavenger but also a cannibal.
While researchers frequently find evidence of bites on bone fossils, Nicholas Longrich was surprised to find big, predator-sized tooth marks on T. rex bones–because the T. rex was the only large carnivore in the area, and therefore the only dinosaur who could have left those marks.
“These animals were some of the largest terrestrial carnivores of all time, and the way they approached eating was fundamentally different from modern species,” Longrich added. “There’s a big mystery around what and how they ate, and this research helps to uncover one piece of the puzzle.” [The Guardian].
Longrich found a total of four bones–three from T. rex feet and one from an arm–that show marks of cannibalism. The location of the bite marks suggest that they were made after death; for example, some of the markings are in areas that would have been obscured by joints in a living animal. One toe bone showed multiple bite marks made by a smaller animal, and Longrich notes that a large T. rex probably wouldn’t let another T. rex gnaw on its foot. There had to be another explanation, Longrich says:
Human remains found at a 7,000-year-old burial site in southwest Germany have markings similar to those found on animals that have been spit-roasted. According to lead researcher Bruno Boulestin, these markings are signs of cannibalism.
The team also found cuts suggestive of meat being scraped from the bones, and bones with the ends broken, as if to facilitate scraping out the marrow. Dr Boulestin said the cuts and markings on the bones provided evidence the bodies of the more than 500 victims, including children and fetuses, were intentionally mutilated, and the victims were butchered and eaten in the same way as animals [Physorg.com]. However, other scientists say the findings, which are published in the journal Antiquity, could have another, less gruesome, explanation.
Members of a tribe in Papua New Guinea has evolved resistance to a affliction similar to mad cow disease (called Creutzfeldt Jakob disease, or CJD, in people). How did they do it? Cannibalism, according to a study in the New England Journal of Medicine.
The Papua New Guinea variant is called kuru, and it was a disaster there. When members of the Fore people in Papua New Guinea died, others would eat the dead person’s brain during funeral rituals as a mark of respect. Kuru passed on in this way killed at least 2500 Fore in the 20th century until the cause was identified in the late 1950s and the practice halted [New Scientist].
The scientists compared DNA samples of about 3,000 living Fore people, some of whom had participated in the old rituals, to 152 samples of stored DNA from Fore that kuru killed. They looked at the genes for prions, ordinary brain proteins that take on a misfolded shape in prion disease such as CJD and kuru. They found a mutation called G127V that protected people from kuru. Only people who ate brains and survived have it, they found [Reuters].
The discovery excited scientists with the possibility of understanding and even treating other prion diseases, like CJD. And British neurologist John Hardy exemplified the scientific glee at seeing human evolution happen in such a short time. “It’s fantastic demonstration of natural selection… In Papua New Guinea kuru became the major cause of death, so there was a clear survival advantage and the selection pressure was enormous” [BBC News].
Discoblog: For Early Europeans, Cannibalism Was One Perk of Victory
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80beats: Female Tarantulas Devour Extra Suitors to Benefit Their Young
Image: D. Carleton Gajdusek
Cannibalistic female spiders who chow down on males do so to give their fertilized eggs a developmental boost, a new study suggests. Researchers found that those Mediterranean tarantulas who ate their suitors produced more offspring, and those spiderlings were stronger and bigger than the offspring of tarantulas that had stuck to more natural prey.
The study turned up several surprises. The researchers watched the tarantulas’ behavior in their natural environments, and saw that the female spiders didn’t eat their mates–instead they waited until after they had mated, and then devoured the next unlucky suitor who came along. Some other studies have suggested that males may sacrifice themselves for the sake of their offspring, but this study showed that, at least in this species of spider, the males are purely unlucky victims and only the babies benefit [Reuters].