The Allies attacking the Japanese on 10 January on Mount Austen. They also attacked two nearby ridges called the Seahorse and the Galloping Horse. The Allies captured all three by 23 January. At the same time, U.S. Marines advanced along the north coast of the island. The Americans lost about 250 killed in the operation while the Japanese suffered around 3,000 killed–about 12 to 1 in the Americans' favor.