In Lost, the DHARMA station that housed polar bears was the Hydra.
The Hydra was a DHARMA Initiative facility located on a separate island near the main island. Its experiments involved animals, including polar bears, and later included research connected with behavior, biology, and the island’s unusual properties.
The station’s name comes from the mythological Hydra, a many-headed serpent. Survivors encounter the facility after being taken to the smaller island, where they discover evidence of DHARMA’s experiments and the Others’ use of the compound.
The polar bears are one of Lost’s earliest major mysteries because their presence on a tropical island seems impossible. Later information connects them with DHARMA’s research and transportation of animals. The Hydra should not be confused with the Swan, Arrow, Pearl, or other named DHARMA stations on the main island.