Humpback Chubs

According to the U.S. Fish and Wildlife Service, humpback chubs (Gila cypha) evolved 3.5 million years ago. Today, in Arizona, they’re found only in the Little Colorado River, the Colorado River and Havasu Creek. Named for the enlarged humps on their necks, the fish can grow to 1.5 feet in length and weigh up to 2.6 pounds. Humpback chubs were protected under the Endangered Species Act in 1973, and recently, management efforts have been fruitful — the Little Colorado River population, in the Grand Canyon, is now estimated at 11,000 fish.