Lassie was a rough Collie, also known as a long-haired Collie. Collies are an American Kennel Club-recognized breed known for their loyalty and high activity levels.
Although Lassie was said to be a female dog, the part was played by several different male collies. This is because males retain their long hair better than females do during the shedding season.
Lassie originated in a short story by Eric Knight titled "Lassie Come Home," which was published in the Saturday Evening Post in December 1938. Books, movies, radio programs and a television series followed the short story about this smart and loyal dog. The television series ran from 1954 to 1962. Although Lassie was supposed to be a female dog, the show used six different males over the years to play the role, said Dog Breed Info Center. Lassie was a tri-color collie, though collies also come in blue merle, sable and white, and white with other color markings, according to About.com Dogs.
Collies are generally very intelligent and graceful. Males and females have similar characteristics, but females shed their undercoats about three times per year every 2 years. Males shed their undercoats once per year. Despite their long coats, Collies do not need excessive grooming. The coat should be brushed regularly, and it is a good idea to trim back the hair around the feet, ears and face.