OK, so the mosquito is only 46 million years old—too recent to have sucked dinosaur blood. But for the first time in history, scientists have found a fossilized skeeter that's still got a belly full of blood, harkening back to the plot of Jurassic Park, the Smithsonian points out. The specimen was actually found by a grad student, Kurt Constenius, 30 years ago in northwestern Montana, but it spent the intervening years in a basement; until now, no one had quite realized its significance.
In 2006, retired biochemist Dale Greenwalt started work at the Smithsonian Museum of Natural History. He read about Constenius' collection, and after doing some work in the same region himself, connected with the Constenius family, who subsequently donated the collection to the museum. That's when Greenwalt spotted the mosquito encased in shale. Testing revealed iron and heme in the abdomen, indicating blood. But don't expect any cloning: For one thing, the DNA is long gone, and scientists can't even say what species the blood came from.