The wolf believed to be the oldest among those transplanted to Yellowstone National Park in 1995 and 1996 has died.
U.S. Fish and Wildlife Service biologist Joe Fontaine said Monday that wolf No. 13, known as “Old Blue” because of its unique slate-gray color, died March 19, apparently of natural causes.
Fontaine said the wolf’s radio collar began sending a “mortality signal” - indicating no movement by the wolf - on that day, and biologists spotted the body during a monitoring flight the same day.
The wolf was found in a rugged area near Heart Lake, reinforcing the belief of biologists that he died of natural causes, Fontaine said.
It would be very difficult to accurately estimate the wolf’s age, but Fontaine said the normal life span in the wild is about 10 years.
“Old Blue” was among the first wolves let loose into Yellowstone as part of the wolf reintroduction program to the northern Rockies in 1995.
The death of wolf No. 13 left the Soda Butte Pack with four wolves - including a female and two pups.
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