Fourteen gray wolves were reintroduced to Yellowstone in 1995. Wildlife officials captured the animals from several packs near Hinton, Alberta, Canada, and transported them to Yellowstone in two shipments: eight arrived on January 12 and six on January 20.
The wolves were held in three acclimation pens—Crystal Creek, Rose Creek, and Soda Butte Creek—in the Lamar Valley of northeastern Yellowstone. Keeping them temporarily confined allowed the animals to become familiar with their surroundings and reduced the chance that they would immediately leave the park. Between March 21 and March 31, 1995, all 14 wolves were released.
The initial group consisted of three family groups. Seventeen more Canadian wolves followed in January 1996, bringing the total number released directly into Yellowstone to 31 across the two years. That is the source of a common quiz mix-up: 14 is the number released in 1995, while 31 is the combined number released in Yellowstone during 1995 and 1996.
The project succeeded because the released wolves reproduced and survived. Officials decided that additional planned releases were unnecessary after the 1996 operation, as a naturally growing population was becoming established.