The gray wolf, the largest canine species in the world, is a keystone predator in northern areas that eats big, hoofed animals such as moose, elk, bison, deer and caribou. They live in the northern hemisphere of America, Europe and Asia. The gray wolf once roamed over two-thirds of the United States until intense hunting threatened the species to extremely low levels in the 1930s.
At one time, gray wolves had the widest distribution of any mammal on Earth except for humans. Canis lupus adapted to life in any biome except tropical rainforests and deserts. Wolves keep ecosystems healthy by eating the weakest or most diseased herbivores when they hunt in packs. These carnivores are increasing in numbers because the species has been reintroduced to areas it once inhabited.
Gray wolves are the ancestors of all domestic dogs tamed by humankind. Despite their common name, these canines actually range in color from brownish gray to black to completely white. Hunting packs number between two and 12 wolves led by an alpha male and alpha female. Members of the pack communicate with each other through barks, howls, growls and whines.
The largest gray wolf ever caught weighed 175 pounds. Most wild specimens live eight to 13 years.