One of the orphaned black bear cubs rescued from the median of Route 58 in Suffolk has died, the Wildlife Center of Virginia reported.

Wildlife rehabilitators at the center found the smaller cub dead in the bear enclosure on Thursday, said Randy Huwa of the Wildlife Center.

“At this point, the veterinary team does not know why [it] died,” Huwa said.

The Southeastern Cooperative Wildlife Disease Study at the University of Georgia will perform a necropsy on the cub, Huwa said. It likely will take several weeks to receive the results.

The two cubs were found Monday morning after their mother apparently was struck by a vehicle on U.S. Route 58, near the landfill. Several motorists called 911 to report the body on the side of the road and the bear cubs wandering aimlessly.

By the time police arrived, the cubs had escaped danger from the traffic by climbing trees. Workers with the Virginia Department of Game and Inland Fisheries arrived, shot the cubs with tranquilizers and transported them to the Wildlife Center.

They weighed about 21 and 23 pounds upon arrival, center officials said. The center’s veterinary team performed physical examinations on the cubs, drew blood for diagnostic tests and did skin-scraping tests to check for mites.

Dr. Dave McRuer, director of veterinary services at the Wildlife Center, said the smaller bear was malnourished upon arrival.

“You can feel his ribs and his spine. He doesn’t have a lot of muscle on him,” he said. “He definitely needs more food.”

But other than being small, both bears were in good condition, he said Tuesday.

Huwa said Thursday the remaining bear cub would be monitored closely over the next few days.