1978 USFWS developed a wolf recovery plan with Two criteria.

USFWS issued a final rule reclassifying the gray wolf as endangered in Minnesota and threatened across the rest of the lower 48 states. The reclassification of the Gray Wolf In the United States and Mexico, with Determination of Critical Habitat in  Michigan and Minnesota

1. Survival of the wolf in Minnesota assured, and
2. At least 1 viable population of eastern timber wolf outside of Minnesota and Isle Royal in lower 48 states is reestablished.
   200 wolves for 5 years within 100 miles from Minnesota, or 100 wolves for 5 years if beyond 100 miles from Minnesota.