This juvenile male nyala is showing signs of reaching maturity, such as the emergence of the horns, less apparent side strips and the fur color transition from rust to a slate gray. But it will be awhile before this antelope from Southern Africa will have spiraled, yellow-tipped horns that can extend up to three feet and weigh as much as 300 pounds. They tend to rest like this during the heat of the day, even in the California sun at Safari West in Santa Rosa.