MANSFIELD, Mass.—A solitary sheep is living life in the fast lane.

An animal shelter worker spotted the sheep last week grazing just feet from traffic on a wooded highway median near Mansfield.

How it got there is a mystery but police first received reports of the animal about a year ago at the junction of Interstates 495 and 95. A number of rescue efforts have failed because the animal is afraid of people, and authorities are wary of using tranquilizers because a drugged animal could wander onto the road. North Attleboro shelter volunteer Linda Faber contacted a sanctuary in New York that offered some suggestions for catching the sheep. One idea is to set up a pen with another sheep to take advantage of the flock instinct. “The longer that the sheep is there, the more likely he or she will be too wild to approach, and the most likely problem of course is that the sheep will be injured by a motorist,” said Susie Coston, national shelter director for the Farm Sanctuary in Watkins Glen, N.Y.