San Clemente Island goats developed naturally when domestic goats were allowed to run feral on San Clemente Island, located 68 miles (110 kilometers) west of San Diego, California. Though the exact genealogy of San Clemente Island goats is a puzzle, researchers believe they were brought to the island from neighboring Santa Catalina Island in 1875, and it was from these Spanish goats that the San Clemente Island goat developed.

In 1934, the U.S. Navy took ownership of San Clemente Island, and a 1972 census found that 15,000-18,000 goats were living on the 57 square mile (91.7 square kilometer) island. These feral goats were causing devastation to the island’s natural ecosystem.
In order to restore the natural habitat, the Navy began goat-eradication programs that would continue until April 1991 when the island was completely goat free. During this time, some 6,000 live animals were returned to the mainland to be re-domesticated. However, many of the males were neutered, so only a small breeding population survived. San Clemente Island goats are one of the rarest domestic animal breeds in the world. There are estimated to be only about 250 San Clemente Island goats worldwide, and they are designated as critically endangered by the American Livestock Breeds Conservancy.

The San Clemente Island goat is a small breed, with males, or bucks, averaging a height of 23.6 inches (60 centimeters) and females, or does, a height of 22.4 inches (56.8 centimeters). This small size is likely the result of insular dwarfism from adapting to island life. These goats have a tan to dark-red coat with black markings. They are lean and have graceful movements that are considered “deer-like.” Both males and females have horns, and it is not uncommon for females to exhibit supernumerary, or extra, teats on their udders.