The wolf gave birth to five pups in May 2008, according to the zoo.
One of the Salisbury Zoological Park's two female red wolves was found dead in her exhibit Friday morning, according to zoo officials.
The older of the zoo's two female red wolves, the 13-year-old obtained by the zoo from the Virginia Living Museum in December 2007, is thought to have died from natural causes. The wolf had been part of an exhibit on red wolves that originally opened on Earth Day in April 2008.
Medium-sized red wolves have a life expectancy between 10 and 15 years, however, the zoo's veterinarian will perform a necropsy to determine a more exact cause of death.
The wolf gave birth to five pups in May 2008, four of which were sent to zoos and wildlife refuges in North and South Carolina, according to the zoo.
Originally declared an extinct wild species in 1980, the red wolf was reintroduced to protected areas in eastern North Carolina and is protected by the federal Endangered Species Act after years of government sponsored hunting in the country's early beginnings.
The zoo will be working with Red Wolf Species Survival Plan for the next two months to develop a plan to best sustain the wolf's captive population in the region as well as the Salisbury Zoo red wolf program.