Against all odds, gray wolves have managed to return from the brink of extinction--a cause for celebration considering how vital they are to keeping the ecosystem in balance. | National Geographic TV

Wolf sounds

The timberwolves of Yellowstone, more commonly known as gray wolves (Canis lupus), were reintroduced to the park in 1995 after being absent for nearly 70 years due to hunting and eradication efforts. These wolves have since played a crucial role in restoring the park’s natural ecosystem by controlling elk populations, which had overgrazed vegetation in the absence of predators. Yellowstone’s gray wolves can vary significantly in size. Adult males typically weigh between 100-130 pounds (45-59 kg)