It’s memorable, all right, but there’s one thing the film missed: The piles of dino dung were likely cleaned up before they could reach such massive proportions, according to a new study published in the online journal PLOS ONE.
We all know dinos didn’t enjoy the luxury of modern plumbing, and there were no sewage tanks back then. The job of keeping the landscape sterile was left to a much smaller worker: the cockroach. More specifically, cockroaches from the now-extinct Blattulidae family.
Peter Vršanský of the Geological Institute at the Slovak Academy of Sciences in Bratislava, Slovakia, figured this out almost by mistake. When he started his study, he was researching the diet of the ancient Blattulidae cockroaches, and he expected it to resemble the diets of other cockroaches from the period.
None of the others dined on dinosaur dung, so it wasn’t even on the research team’s radar. (Also see “The Scoop Behind Ancient Poop.”)
But then they cracked open a fossilized cockroach, which had been discovered in an amber deposit from Lebanon, and studied it with synchrotron x-ray microtomography, a technique that allowed them to create a virtual 3-D version of the cockroach instead of picking apart the original.
They were surprised to find wood particles that were large in comparison to other particles in the cockroach.
“The occurrence of any wood … was entirely unexpected,” the authors wrote in the study. The particles had smooth edges, indicating that the cockroach had not munched on them.
The particles were also more decomposed than a cockroach’s digestive system would’ve been able to accomplish, which further supports the researchers’ hypothesis that “the wood they ate was digested before it entered the cockroach,” said Vršanský.
So who noshed on those wood particles first? Dinosaurs!
“There is no other possible source of wood. The wood fragments are apparently pre-digested, and nobody at that time could eat fresh wood,” Vršanský added. (Also read “Talking Poop With Author of ‘The Origin of Feces.'”)
Vršanský says that during the Mesozoic period, cockroaches were the most common insect in most areas. Modern cleaner-uppers like dung beetles and flies weren’t around during the Triassic or most of the Jurassic periods, which cover about half of the span of the dinosaur era.
The Blattulidae cockroaches were not like the modern, wood-eating cockroaches and termites that we deal with today. But, the authors added, the link between dino poop and cockroaches didn’t die with the dinosaurs, or with the Blattulidae family—several modern cockroaches feast on the feces of birds, known dinosaur descendents. It looks like some eating habits are hard to break.
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