Water toads (Bufo stejnegeri) are an unusual, peculiar species of toad that are found in Korea and northeastern China. As their name suggests, they are highly aquatic, very unlike other species of toads. They form breeding pairs in the autumn, and apparently overwinter amplexed under water, ready to breed early in the spring. We focus on mate choice, population structure, and genetic analyses of MHC variation in relation to disease resistance. Moonsuk Cha is the main researcher in this project.