Believed to be an ancestor of the domestic dog, the wolf is generally regarded as a highly intelligent hunter. Wolves travel in (1) packs and their territory can be anywhere from 40 to 400 square miles. As well as marking the borders of their territory with scent, they (2) let other wolves know they are around by barking and howling.

A pack might consist of up to 30 wolves, although where the food supply is limited there might only be six or seven animals in the pack. When hunting, they work together to chase an animal, block its escape, and finally (3) catch it. In this way, they are (4) able to trap large animals, such as deer or moose.

If farm animals are available, they (5) provide the wolves with an easy source of food. This, of course, brings them into (6) conflict with humans. Poisoning and shooting have (7) led to the decline in wolf populations around the world. The red wolf is now almost (8) extinct in the wild, while the grey wolf has had its (9) range reduced to a few areas in Europe, North America and Asia. Like many other large mammals, the wolf is increasingly under (10) threat from human activity.