Fossils of these large bugs were found in China. One female was found to be about 20 millimeters long, whereas a large male reached 15 millimeters. Those dimensions may seem small, but the fleas were actually massive. Imagine that, a 2-centimeter (0.7-inch) flea on your leg.
Like their more modern counterparts, the creatures did not have any wings. Unlike today's fleas, they also did not have the extremely specialized hind legs, to allow them to jump so high and far, Science Now reports.
To make matters worse for the poor feathered reptiles, the fleas had specialized organs for siphoning blood from between thick hides, a type of armor that mammals did not have 165 million years ago.