Don't mess with their acorns.
Cronopio was shrew-sized, about 4-6 inches in length, and was an insectivore with a diet of the insects, grubs and other bugs of the time. It lived when giant dinosaurs roamed Earth -- more than 100 million years ago -- and made its home in a vegetated river plain.
The skulls reveal that Cronopio had extremely long canine teeth, a narrow muzzle and a short, rounded skull. "These first fossil remains of dryolestoids … give us a complete picture of the skull for the group," John R. Wible, Ph.D., curator of mammals at the Carnegie Museum of Natural History, said. "The new dryolestoid, Cronopio, is without a doubt one of the most unusual mammals that I have seen, extinct or living, with its elongate, compressed snout and oversized canine teeth. What it did with that unusual morphology perhaps may come to light with additional discoveries… ."