It’s not just dogs and cats that are unsafe from flea bites; even dinosaurs have fallen prey to huge blood sucking pests millions of years ago.
Palaeontologists have discovered giant fossil fleas in Inner Mongolia and Liaoning province of China dating back 165 million years.
The insects were not quite like fleas as we now know them. The huge pests found measured as much as ten times the size to the biggest fleas living today.
George Poinar, Jr., a professor emeritus of zoology at Oregon State University, who is an international expert in ancient and extinct insect life forms stated, "These were insects much larger than modern fleas and from the size of their proboscis we can tell they would have been mean.
"These are really well-preserved fossils that give us another glimpse of life into the really distant past, the Cretaceous and Jurassic."
"You wouldn't talk much about the good old days if you got bit by this insect. It would have felt about like a hypodermic needle going in -- a flea shot, if not a flu shot. We can be thankful our modern fleas are not nearly this big.” — George Poinar
Evolutionary ancestors of modern fleas
According to the scientists, the primitive giant fleas called Pseudopulex jurassicus and Pseudopulex magnus exhibit many defining features and traits of modern fleas.
There is a strong possibility that the insects found in fossils are the evolutionary ancestors of modern fleas, but are now an extinct lineage.
They had flat bedbug like bodies and disproportionately stout and elongated sucking claws with serrated edges for piercing scaly hides of their victims.
This suggests that the primitive bugs latched onto a variety of hairy or feather-covered animals, perhaps even dinosaurs, feeding on the softer skin between scales.
Experts theorize that the ancient flea may have crept up on sleeping dinosaurs, crawling onto their soft underbellies and then delivering an unusually painful bite that would have felt like a needle going in.
In contrast, the modern fleas are laterally compressed and have shorter antennae that help them move quickly through the fur or feathers of their hosts.
"You wouldn't talk much about the good old days if you got bit by this insect," Poinar said. "It would have felt about like a hypodermic needle going in -- a flea shot, if not a flu shot. We can be thankful our modern fleas are not nearly this big.”
According to scientists, after the dinosaurs became extinct about 65 million years ago, the early fleas moved to living on mammals and birds and in the process they scaled down in size.
The new discovery is detailed in the journal 'Current Biology.'