Trilobites: Gray Ghosts, the Last Caribou in the Lower 48 States, Are ‘Functionally Extinct’ The herd of southern mountain caribou, the last in the contiguous United States, has dwindled to three animals. Conservationists attribute the decline to development in Canada. Share: Facebook Twitter Google+ Stumble Digg Email ThisBlogThis!Share to XShare to Facebook Related Posts:Q&A: How the Humble Bean Went GlobalNeil Armstrong Walked on the Moon Nearly 50 Years Ago. Do You Remember That Day?The Cycle: Why I Wanted to Learn to Perform AbortionsSloan Kettering Researchers Correct the Record by Revealing Company TiesCindy R. Lobel, Who Traced New York History Through Food, Dies at 48After Nobel in Economics, William Nordhaus Talks About Who’s Getting His Pollution-Tax Ideas Right