(Trioceros jacksonii)
Jackson's chameleon, Jackson's horned chameleon, three-horned chameleon, or Kikuyu three-horned chameleon (Trioceros jacksonii) is a species of chameleon (family Chamaeleonidae) native to East Africa, but also introduced to Hawaii, Florida, and California. Jackson's chameleon was described by Belgian-British zoologist George Albert Boulenger in 1896. The generic name, Trioceros, is derived from the Greek τρί- (tri-) meaning "three" and κέρας (kéras) meaning "horns". This is in reference to the three horns found on the heads of males. The specific name, jacksonii, is a Latinized form of English explorer and ornithologist Frederick John Jackson's last name, who was serving as the first Governor of Kenya at the time. The English word chameleon (also chamaeleon) derives from Latin chamaeleō, a borrowing of the Ancient Greek a compound of χαμαί (khamaí) "on the ground" and (léōn) "lion". The Greek word is a calque translating the Akkadian, "ground lion". Jackson's chameleons are native to woodlands and forests at altitudes of 1,600 to 2,440 m (5,250 to 8,010 ft) in south-central Kenya and northern Tanzania. In these areas, the rainfall is seasonal but exceeds 127 cm (50 in) per year. Day temperatures are typically 16–27 °C (61–81 °F), and night temperatures are typically 4–18 °C (39–64 °F). In Tanzania, it is known only from Mount Meru in the Arusha Region, which is the home of the relatively small endemic subspecies T. j. merumontanus. Jackson's chameleon is more widespread in Kenya, where it is even found in wooded areas of some Nairobi suburbs. The subspecies T. j. xantholophus (native to the Mount Kenya region) was introduced to Hawaii in 1972 and has since established populations on all main islands and became an invasive species there. This subspecies has also been introduced to Florida. In Hawaii, they are found mainly at altitudes of 100 to 1,000 m (330 to 3,280 ft) in wet, shady places. Historically this population was the primary source of Jackson's chameleons for the exotic pet trade in the United States, but exports from Hawaii are now illegal. This has been done to prevent opportunists from willfully establishing further feral animal populations to capture and sell them.