Bart the Bear (born 2000), nicknamed "Little Bart," is a trained Alaskan Kodiak actor-bear. Born in 2000, Little Bart is named after the (unrelated) Bart the Bear, who starred in several major films, and who died the same year that Little Bart was born.
Little Bart has appeared in Dr. Dolittle 2, CSI, Scrubs, and Into the Wild.
Little Bart appears in episode 7 of Season 3, the aptly named "The Bear and the Maiden Fair", in which Brienne of Tarth is thrown into a bear pit to fight for the amusement of her captors from House Bolton.
As director Michelle MacLaren explained, she chose Bart out of three potential stunt-bears: one from Utah (Bart), one from Canada, and one from Europe. Bart was then flown from Utah to California, where a partial duplicate of the bear pit set at Harrenhal was built in a Los Angeles studio parking lot. Just the pit part was built: the extras crowded around the top of the pit were filmed on the full set in Northern Ireland. Gwendoline Christie (Brienne of Tarth) and Nikolaj Coster-Waldau (Jaime Lannister) were the only cast members flown out to Los Angeles, to film on-set with the bear. The footage from within the pit was then digitally married with the footage of the extras crowded around the top on the duplicate set. Christie explained that she was actually with Bart the bear in the pit, though in real life the crew was being friendly to the bear and saying encouraging things to keep him calm. Christie said that she did every stunt in the bear pit - except for one, when she has to pretend that the bear is hitting her. A stunt double was used for that specific, brief shot, though in real life Bart was just playfully pawing at the stunt man.