Overview
With three forward-pointing horns and a ridged back, the male Jackson’s chameleon looks almost prehistoric. In Tanzania, this remarkable reptile is known from the forests of Mount Meru, where the local form is the Mount Meru Jackson’s chameleon, Trioceros jacksonii merumontanus.
Jackson’s chameleons favour cool, humid, well-vegetated environments. They move slowly through branches and shrubs, gripping tightly with specialised feet and a prehensile tail. Their deliberate pace helps them remain hidden while they scan for insects with independently moving eyes.
Like other chameleons, they change colour for communication, temperature control and responses to stress. Their long, rapidly extending tongues allow them to catch insects from a distance with impressive speed and accuracy.
Behaviour & How to Identify
Look for a green or blue-green chameleon with a strongly ridged back, a long curling tail and a prominent casque at the rear of the head. Adult males typically carry three horns: one on the nose and two above the eyes. Females usually have much smaller horns or may lack obvious horns altogether.
Their feet are arranged into opposing bundles of toes that grip branches like pincers. The tail can wrap around twigs and stems, providing extra support while the animal climbs.
Each eye can move independently, allowing the chameleon to survey a wide area without turning its head. Once prey is detected, both eyes focus forwards to judge distance before the tongue is projected. Males may become territorial and use colour changes, body flattening and horn-to-horn pushing contests when confronting rivals. Their horns are used mainly in these visual and physical displays rather than for hunting.
Interesting facts
The Tanzanian population belongs to a distinctive Mount Meru form. Trioceros jacksonii merumontanus is restricted to Mount Meru in northern Tanzania.
They give birth to live young. Unlike many chameleons that lay eggs, Jackson’s chameleons retain the developing young inside the body and give birth to fully formed juveniles.
Their eyes work independently. One eye can look ahead while the other scans behind, giving the chameleon an exceptionally wide field of view.