The platypus has fur, is warm-blooded, and suckles its young as do mammals. It lays leathery eggs, has a single ventral opening (for elimination, mating, and birth), and has claws and a shoulder girdle as most reptiles do. The platypus can detect electrical currents (AC and DC) as some fish can, and has a bill somewhat like a that of a duck—a bird. It has webbed forefeet like those of an otter and a flat tail like that of a beaver. The male platypus can inject poisonous venom like a pit viper.