Jackson's chameleon
A three-horned chameleon native to East Africa, invasive in Hawaii.
Wikipedia / Wikimedia Commons
Jackson's chameleon (Trioceros jacksonii), also known as Jackson's horned chameleon, the three-horned chameleon, and the Kikuyu three-horned chameleon, is a species of chameleon in the family Chamaeleonidae. Native to East Africa, it has been introduced to Hawaii, Florida, and California, where it can become invasive. The species is notable for the three horns on males and its ovoviviparous reproduction.
- Scientific name
- Trioceros jacksonii
- Described by
- George Albert Boulenger (1896)
- Native range
- South-central Kenya and northern Tanzania
- Introduced range
- Hawaii, Florida, California
- Recognized subspecies
- 3 (T. j. jacksonii, T. j. merumontanus, T. j. xantholophus)
- Adult male length
- Up to 38 cm (15 in)
- Adult female length
- Up to 25 cm (10 in)
Lore & Background
Jackson's chameleon was described by Belgian-British zoologist George Albert Boulenger in 1896. Its generic name Trioceros derives from Greek for 'three horns,' referring to the three brown horns on males: one on the nose and one above each eye. The specific name jacksonii honors English explorer and ornithologist Frederick John Jackson, then Governor of Kenya. Three subspecies are recognized: the nominate T. j. jacksonii, the dwarf T. j. merumontanus from Mount Meru, and the yellow-crested T. j. xantholophus from the Mount Kenya region.
Reader's Guide
Jackson's chameleon is significant as an arboreal lizard native to highland forests of Kenya and Tanzania, but its introduction to Hawaii in 1972 via the subspecies T. j. xantholophus has made it an invasive species with substantial threat to native biodiversity. In Hawaii, it preys on endemic invertebrates, including critically endangered O'ahu tree snails (genus Achatinella), and has been found to consume land snails, insects, and other small animals. Historically, the Hawaiian population was the primary source for the U.S. exotic pet trade, though exports from Hawaii are now illegal to prevent further feral populations. The species is ovoviviparous, giving birth to live young after a five- to six-month gestation. In captivity, it requires high humidity and cool night temperatures, with a lifespan of five to ten years. Its territorial behavior is less aggressive than many chameleons, relying on color displays and posturing.
Did You Know?
- Males possess three brown horns, reminiscent of the dinosaur genus Triceratops.
- It is ovoviviparous, giving birth to 8–30 live young after a 5–6 month gestation.
- The subspecies T. j. xantholophus was introduced to Hawaii in 1972 and is now invasive there.
- It swallows whole snails, including the shells, in its diet.
Frequently Asked Questions
Who is Jackson's chameleon?
Jackson's chameleon (Trioceros jacksonii) is a medium-sized chameleon in the family Chamaeleonidae, formally described by George Albert Boulenger in 1896. It is widely recognized by the three keratin horns on adult males and is also called the three-horned or Kikuyu three-horned chameleon.
What are Jackson's chameleon's most notable traits or 'powers'?
Adult males reach up to 38 cm (15 in) and display two supraorbital horns plus one rostral horn, while females are hornless and slightly smaller. The species also reproduces ovoviviparously—females deliver live young rather than laying eggs, a trait that sets it apart from many other chameleons.
Where does Jackson's chameleon live, and where has it been introduced?
Its native range is confined to south-central Kenya and northern Tanzania in East Africa. It has since been established in Hawaii, Florida, and California, where it can behave as an invasive species and outcompete local fauna.
How many subspecies of Jackson's chameleon are recognized?
Three subspecies are currently acknowledged: T. j. jacksonii, T. j. merumontanus, and T. j. xantholophus. They are distinguished mainly by differences in horn length, shape, and subtle coloration variations.
Why is Jackson's chameleon important to ecology and conservation?
Its striking three-horned appearance makes it a popular subject in the exotic-pet trade, which in turn drives illegal collection pressure on wild populations. In regions like Hawaii, introduced groups have become established and now pose a genuine threat to native invertebrate and plant communities, making the species a textbook case of unintended biological invasion.
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