This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
It only took about half a century, but the once-rare Delmarva fox squirrel (Sciurus niger cinereus) now has a healthy population once again, placing it in a position to finally leave the protection of the Endangered Species Act (ESA). If that happens, this giant squirrel—which can reach an astonishing 75 centimeters in length—would join just 29 other species that have been declared recovered under the ESA.
The Delmarva fox squirrel has enjoyed legal protection since 1967, predating the Endangered Species Act of 1973. At the time it was declared endangered, the subspecies had lost 90 percent of its historic range, which once included almost the entire 274-kilometer Delaware peninsula for which it is named as well as areas of Pennsylvania and New Jersey. Deforestation and other habitat loss during the first half of the twentieth century pushed the squirrel out, while hunting also took a heavy toll. By the 1960s the subspecies could only be found in a few Maryland counties.
Endangered-species protection brought an end to the squirrel hunting season, but the real key toward recovering the Delmarva squirrel turned out to be private landowners. Biologists with the U.S. Fish and Wildlife Service (FWS) relocated squirrels onto several large Maryland farms where they thrived. Other reintroductions took place on national wildlife refuges, but today 80 percent of the squirrel's expanded habitat consists of private lands. The squirrel has now regained approximately 28 percent of its historic range and its population (estimated at between 17 and 20,000) is stable, widely distributed and, according to the FWS, healthy enough to withstand any future threats that might arise from disease or habitat loss, or even sea-level rise (which, FWS predicts, will result in some deforestation along the Chesapeake Bay and Atlantic Coast).
On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
The process to delist the squirrel from the ESA isn't quite over. The public is invited to submit comments or other supporting information on the proposal to delist the species. Comments are due by November 24. Assuming no new information about previously unassessed threats comes in during that process, it would then take another few months before the squirrels were delisted. Even then, FWS would continue to monitor the squirrels for several years to make sure their populations remain healthy outside the protection of the ESA.
It has been a long road to recovery for the Delmarva fox squirrel, but hopefully the journey is just about completed.
Photos: USFWS