There are four endemic snake species on Grand Cayman and two invasive species. They are all relatively harmless and the largest is the rarely seen invasive corn snake, which may grow to about 5 feet (1.5 m). The smallest averages 2–4 inches (5–10 cm) and is the invasive brahminy blind snake which is also rarely seen. The most common is the endemic Cayman racer snake. It can grow to approximately 5 feet (1.5 m), but 3-foot (91-cm) specimens are much more common. These snakes tend to race away if encountered and in rare cases will rear up in a threatening manner if cornered. The Cayman racer snake carries a mild venom which it uses to immobilise prey, but in large enough doses it can cause significant swelling and bruising if it latches on for an extended period. A simple bite and release does not usually cause any reaction in humans. The other three endemic snake species are the Cayman ground boa, Cayman blind snake and Cayman water snake.