1. The problem asks to identify which animal in the wild went extinct in the 1800s according to the North American Model of Wildlife Conservation. 2. The options given are Passenger pigeon, Bison, Elk, and Pronghorn. 3. According to historical records, the Passenger pigeon is the animal that went extinct in the 1800s. 4. The Bison, Elk, and Pronghorn were severely reduced in number but did not go extinct. 5. Therefore, the correct answer is Passenger pigeon.