Sep. 04, 2012

Delmarva Peninsula's Endangered Squirrel

by Kara Rogers

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The Delmarva fox squirrel is a very, very large squirrel. It can tip the scales at as many as three pounds, which is about twice the size of its cousin, the Eastern gray squirrel. But it otherwise has all the typical squirrel traits -- a long tail, small, round ears, and an acorn-shaped head.
 
Unlike the prolific Eastern gray (Sciurus carolinensis) -- the squirrel most people in the United States are familiar with -- the Delmarva fox squirrel (Sciurus niger cinereusis) is an endangered species. By the mid-1960s, it was reduced to just 10 percent of its natural range on the Delmarva Peninsula, which juts out between the Delaware and Chesapeake bays along the Atlantic Coastal Plain. (“Delmarva” is a combination of the names of the states that share the peninsula: Delaware, Maryland, and Virginia.)
 
Much of the Delmarva fox squirrel’s preferred habitat, which consists of mature mixed pine and hardwood forest, was cleared for agriculture or converted for timber production in the 19th and early 20th centuries. During that time, the species was hunted for food by humans, which compounded the effects of predation by others animals, such as foxes, minks, and raptors.
 
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The Delmarva fox squirrel was added to the U.S. Endangered Species List in 1967, giving momentum to habitat protection projects begun in the 1940s in Maryland. Hunting of the species was banned in 1971, and in that decade and the following, biologists carried out a series of translocations, in which groups of squirrels from existing populations were introduced to uninhabited sites within the species' historical range. Translocations at various sites were successful.
 
Had recovery efforts failed, the Delmarva fox squirrel might not be here today, and that would have been a great tragedy. The species is truly unique among tree squirrels (genus Sciurus). It is a shy animal and is beautiful. It has a silvery gray coat, white feet, and an unusually fluffy, white- and black-accented tail. The fluffiness of its tail resembles that of a fox's, explaining its common name.
 
The Delmarva has adapted its behavior to occupy a niche distinct from that of the Eastern gray squirrel. The main difference between the two is that the Delmarva prefers to stick to the ground. It nests in trees and will run up trees to flee from predators, but it spends most of its time foraging for nuts and seeds in the open understory of mature forests and in open areas along streams and fields. It frequently travels by running along the ground, rather than by leaping between the branches of trees, which is typical of the more agile, tree-dwelling Eastern gray.
 
While the Delmarva's numbers have increased, habitat fragmentation and residential development have left populations isolated and vulnerable to catastrophic events, such as disease or natural disaster. To secure a future for the species, biologists continue to monitor populations and to promote habitat protection. The conservation of forest corridors connecting woodlots to ensure safe passage for the squirrel from one area of its habitat to another is one such effort currently underway.
About Kara Rogers

Kara is a freelance science writer and senior editor of biomedical sciences at Encyclopaedia Britannica, Inc. She is the author of Out of Nature: Why Drugs From Plants Matter to the Future of Humanity (University of Arizona Press, 2012).

The views expressed are those of the author and are not necessarily those of Science Friday.

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