What kind of animal is a lurcher?

The lurcher is the offspring of a sighthound mated with another breed, most commonly a pastoral breed or a terrier type of dog. Historically a poacher's dog, lurchers in modern times used as pets, hunting dogs and in racing.

While not a pure breed, it is generally a cross between a sighthound and a working dog breed.

Collie crosses are popular, given the working instinct of a sheepdog when mated with a sighthound gives a dog of great intelligence plus speed—prerequisites for the hunter/poacher. In the US midwest, crosses with large scent hounds are fairly common.

The distinction between a greyhound and a lurcher was more legal than biological. Greyhounds were used to hunt legally by the upper class, while the illegal hunting of the lower orders was reflected in the dog's name: lurcher or "poacher's dog".