Jackson's chameleon is a species of chameleons that are native to East Africa. It was described by Belgian-British zoologist George Albert Boulenger in 1896. Later, this small chameleon was introduced to Hawai. Jackson's chameleons are sometimes called Three-horned chameleons because males possess three brown horns: one on the nose (the rostral horn) and one above each superior orbital ridge above the eyes (preocular horns). The females generally have no horns, or instead, have traces of the rostral horn. Jackson's chameleons are usually bright green in color, with some individual animals having traces of blue and yellow, but like all chameleons, they change color quickly depending on the mood, health, and temperature. They also have a saw-tooth shaped dorsal ridge and no gular crest.
Jackson's chameleons are found in south-central Kenya and northern Tanzania. In Tanzania, they occur only in Mount Meru in the Arusha Region. Jackson's chameleons are more widespread in Kenya, where they are even found in wooded areas of some Nairobi suburbs. These chameleons live in moist montane forests and woodlands. They need cover to hide and prefer to live in trees and thickets. They can also be found in plantations and gardens.
Jackson's chameleons are solitary creatures. They are less territorial than most species of chameleons, however, males generally assert dominance over each other through color displays and posturing in an attempt to secure mating rights, but usually without fights. They may also puff up their body to look larger, hiss and sway from side to side. Jackson's chameleons are active during the day and spend their time hunting and basking in the sun. When hunting chameleons use their sharp vision to locate the prey and when the prey is located they slowly approach it without being detected due to their ability to change the color and blend with the surroundings. Once chameleons get close enough to the prey they use their long tongue to grab it in a split second. Their tongue can be almost 2 times the body length and the muscles in their mouth allow chameleons to move their tongue at great speeds. Jackson's chameleons are very slow and thus are highly vulnerable to predation. To hide from predators they also use the ability to change their skin color as camouflage. However, if they are spotted by a predator, chameleons become completely defenseless.
Jackson's chameleons usually mate in summer. They are viviparous and give birth to live young. Females give birth to 8-30 young after the gestation period that lasts around 5 to 6 months. Newborns are 5 to 6 cm in length and completely independent; they start hunting a few hours after birth. Young Jackson's chameleons become reproductively mature and are ready to mate when they are 9-10 months old.
Jackson's chameleons don't face major threats at present. However, this species is heavily used in the exotic pet trade which could influence their populations in the future.
The IUCN Red List and other sources don’t provide the number of the Jackson's chameleon total population size. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.