Chamaeleo (Trioceros) jacksonii
Chamaeleo (Trioceros) jacksonii Boulenger, 1896, Uganda, later amended to Kikuyu, near Nairobi, Kenya. Two subspecies are recognized.
OTHER COMMON NAMES
English: Mt. Meru chameleon, three-horned chameleon; French: Caméléon de Jackson; German: Ostafrikanisches Dreihornchamäleon.
This species grows to 6-14 in (152-356 mm) in length. Ch. j. xantholophus is the largest, followed by Ch. j. jacksonii and then Ch. j. merumontanus. Males have three annulated (composed of rings) horns, two preorbital and one nasal in all three forms. Females may have no horns, a single nasal horn, or three well-developed horns that are slightly smaller than those of the males, depending on the subspecies. The body coloration is shades of green or brown with a dark red, yellow, or blue wash on the head, flanks, or tail. Juveniles are brown, black, and off-white and show an infusion of adult coloration at about the age of six months.
Ch. j. jacksonii occupies the highland of central Kenya, except the eastern slopes of Mount Kenya. Ch. j. xantholophus lives on the southern, eastern and northeastern faces of Mount Kenya and in Kenya and has been introduced to Hawaii. Ch. j. meru-montanus inhabits Mount Meru in Tanzania at an elevation of 7,500-9,000 ft (2,288-2,745 m).
This is a montane, arboreal species that utilizes various habitat types, including moist forest, exotic plantations, and dense bushes.
Jackson's chameleon is docile and gentle. Males settle territorial and mating disputes by engaging in pushing contests with their horns, but they rarely resort to biting or inflict injury. Females generally are very calm and tolerant of conspecifics.
FEEDING ECOLOGY AND DIET
Jackson's chameleon preys on a wide variety of invertebrates.
Males engage in ritualistic head bobbing to court females. Nonreceptive females become dark, rock, gape, and may grasp the forelegs or horns of an advancing male. If the female is receptive, she lifts her tail to facilitate copulation. Gestation varies from five to nine months, depending on ambient temperatures. The species is ovoviviparous (live-bearing), with births of three to 50 young per clutch, depending on the subspecies.
Jackson's chameleon is listed on CITES Appendix II. Kenya ceased exporting specimens of Ch. j. jacksonii and Ch. j. xan-tholophus in the early 1980s. Hawaii considers feral Jackson's chameleons detrimental to the ecosystem. The species lives mainly in highly degraded habitat and exotic plantations, where it is believed to have adapted successfully to living in close proximity to humans.
The species was exported from Kenya in very high numbers for the commercial pet trade beginning in the 1960s, which was accompanied by very high levels of morbidity and mortality through the 1980s, when Kenya stopped exportation. From 1993 to 1999 more than 12,000 Ch. j. merumontanus individuals were exported from Tanzania, but it is unknown as of 2002 whether this has had a detrimental effect on population densities. This subspecies did not adapt well to captivity, and reproduction is poor. Several generations of Ch. j. xantholophus originating from Hawaii were bred in captivity in the 1990s but only by a very few people worldwide. ♦
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