A 57-year predator study will likely be forced to shift directions as early as next year because the wolf population it studies is nearly extinct. Since 1958, scientists have tracked the ebbing wolf population on Michigan's Isle Royale, an island in Lake Superior. Now the study is down to only three predators, and that number may reach zero by as early as next year, according to a report in Nature.

In the 1940s, three Canadian gray wolves walked across the ice on Lake Superior and found a home on Isle Royale, according to the National Parks Conservation Association. The population of moose already on the island made the animals' prey / predator relationship enticing to scientists.

The last male wolf to join the pack was in 1997, and the researchers say the inbreeding has created problems, Nature reports. Originally, Rolf Peterson and John Vucetich, ecologists at Michigan Technological University, hoped to save the population by bringing new wolves onto the island whose dominant genes would mask faulty recessive genes. But Peterson and Vucetich say the National Parks Service dragged its heels when the researchers asked to introduce new wolves, and the period for "genetic rescue" has closed.

"We have science coming out our ears and it wasn’t enough to carry the day against an entrenched bureaucracy with a culture of non-intervention," Peterson told Nature.

Last month, the US National Science Foundation renewed the study's five-year grant for $90,000, so the study can continue without wolves. The researchers can track moose — whose population on the island has reportedly increased by about 22 percent per year — and vegetation.