DID DINOSAURS HAVE FLEAS?
The fossil record tells us that the first insects evolved around 480 million years ago, while the first fleas evolved later, somewhere between 290 and 165 million years ago. Dinosaurs made their debut during the Triassic Period, around 225 million years ago, so dinosaurs and fleas were around at the same time.
To know if fleas bit dinosaurs we would need to find a fossil specimen caught in the act of feeding, but so far, palaeontologists have never uncovered such a relic. What they have found, however, are fossil fleas with adaptations that suggest they dined on dinosaurs.
In 2012, scientists examined some fossil fleas unearthed from two sites in China. The fleas, believed to be between 165 and 125 million years old, were whoppers, about the size of a 10p piece (almost the same as a 25¢ coin), with long, tubular mouthparts. This feeding apparatus was stout and serrated, overkill for parasitising birds and mammals, but more than enough to pierce the comparatively tough hides of small, feathered dinosaurs, such as Sinosauropteryx and Epidexipteryx.
Unlike modern fleas, which are notoriously excellent jumpers, the Cretaceous critters were scramblers. Instead of leaping onto their hosts, they would have waited for an opportunity and then clambered aboard. They had bristly, flattened, wingless bodies, long legs and claws, but thankfully, for anyone who is acarophobic (frightened of lice and fleas), they went extinct a long time ago, along with the thick-skinned, blood-filled animals they fed on.
We do have fleas that feed on dinosaurs today, though. Birds are the descendants of avian dinosaurs, so from a geeky, taxonomical perspective, they are dinosaurs. There are an estimated 2,500 species of fleas, the vast majority of which feed on mammals. But that still leaves around 400 species that chomp on our modern-day dinosaurs. Delicious!