Somewhere around 400,000 years ago, hulking elephants made their way to what we know now as the Italian island of Sicily. In a relative blink of the eye—roughly 40 generations—they shrank to miniature versions of their former selves, reports the New York Times. That's one estimate provided by scientists in the journal Current Biology. Through analysis of ancient fossils of dwarf elephants on the island, they found that the creatures descended from behemoths that stood 12 feet tall and weighed 10 tons. But after the elephants arrived on the island—perhaps by swimming or a long-gone land bridge—a lack of food appears to have forced a quick change in stature. Researchers say that over 1,300 years, the elephants may have lost roughly 440 pounds per generation, according to Nature.
"We know that evolution can be rapid, but this is a striking example," says Mirte Bosse of Wageningen University in the Netherlands, who was not involved with the study, per the Times. The island elephants eventually shrank to a height of 6 feet and a weight of 1.7 tons, per Gizmodo. For context, the researchers say this would be like a human shrinking to the size of a rhesus monkey. It's possible the reduction in size played out over a longer stretch, but the 40-generation estimate—based on analysis of mitochondrial DNA—is at the fast end of the range. "The magnitude of dwarfing resulting from this rapid evolutionary process is truly striking, resulting in a loss of body mass of almost 85% in one of the largest ever terrestrial mammals," says study author Axel Barlow of the UK's Nottingham Trent University in a release. (Read more elephants stories.)