East Africa, namely Kenya and Tanzania. (Zimmermann, 1986).
Biogeographic Regions: ethiopian (Native )
occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: Native to East Africa. Introduced in Hawaii via pet trade in early 1970s; now well established on Oahu, Hawaii, and Maui, and recently recorded on Kauai and Lanai (McKeown 1996). Also introduced and established in Los Angeles, San Diego, and San Luis Obispo counties, California (McKeown, 1997, Bull. Chicago Herpetol. Soc. 32:101).
Distribution: Kenya (Kikuyu near Nairobi, highlands of central Kenya except of eastern slopes of Mt. Kenya), Tanzania (Mt. Meru), Kenya (eastern slopes of Mt. Kenya) USA (Chamaeleo jacksonii xantholophus was introduced to Hawaii fide McKeown 1996) merumontanus: Tanzania (Mt. Meru)
Type locality: Laikinoi, Mt. Meru, Arusha District, Tanzania [merumontanus]
Most are approximately 15-35 cm in length. They normally display varying shades of green but can turn as dark as black when in great distress. They are sexually dimorphic. Males have three long, pointed horns protruding from the head. These horns are absent or poorly developed in females. The back of the head displays a small crest. There are small spines along the vertebral line. Like other chameleons, Jackson's chameleon has zygodactylus feet (divided so that two toes point inward and three point outward) which are specialized for tree life, and a prehensile tail which is also used for gripping (Capula, 1989).
The most recognizable feature of all chameleons, however, are their eyes. The pupil is the only part visible from its covering of skin. Each eye rotates a full 180 degrees and is independent of the other. Chameleons have unusually strong control over the curvature of their lenses, and may actually magnify an image. (Land 1995)
Length: 25 cm
Jackson's chameleons prefer to live in mountain thickets and forests. They need cover to hide in and prefer to live in trees(Bartlett and Bartlett, 1995). They rarely venture to ground except to lay eggs or mate.
Terrestrial Biomes: rainforest
Comments: Arboreal, specialized for living in trees and bushes. Hawaii: forests, orchards, wooded gardens.
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
This chameleon's diet consists mainly of insects and spiders. Using their eyes independently, they will sit completely still and watch for a prey item to cross their path. When one is spotted, both eyes will converge and it will sway a bit to better its vision and to confirm the distance to the meal. Prey is captured by projecting the tongue, which has a fleshy tip covered with sticky saliva. Prey is then brought back into the mouth, chewed and swallowed (Bartlett and Bartlett, 1995). The tongue, one and a half times the lizard's length, can reach full length in a sixteenth of a second.
They obtain water by lapping drops off leaves.
In the morning, they will sun themselves, curving one side towards the light and flattening out their bodies and stretching their necks to increase their surface area. Once warmed, they are able to hunt.
Comments: Eats various climbing and flying invertebrates, including grasshopper, crickets, cockroaches, flies, butterflies, moths, spiders, slugs, and snails (McKeown 1996); prey captured with projectile tongue.
Life History and Behavior
Status: captivity: 8.2 years.
Lifespan, longevity, and ageing
Jackson's chameleons have a mating ritual that mimics their threat ritual. The male will initiate the threat display to the female which includes color changes, throat inflation and raising the forelegs toward the opponent. The female then has two choices. She can make threatening gestures back, in which case she does not want to mate. If she does want to mate, she will make weak threatening gestures or make no gesture at all in which case the male recognizes her willingness. The male then will circle around the female, grab her neck in his mouth and pull himself on to her back, and insert his hemipenis into her cloacal opening. This entire process usually lasts about 13 minutes. The female will continue mating for 11 days but with not with the same male twice in one day. Gestation lasts approximately 190 days. The young are usually born in the morning. The female everts her cloaca and the young are delivered one at a time onto a branch. They are still surrounded by a gelatinous egg sac and remain asleep until the egg touches the substrate. The young then awaken and stretch and break through their egg sac. At birth young are about 5.5 cm long and weigh around .6 gm. After 20 days the females will copulate again. The young will reach sexual maturity at the age of 9 or 10 months (Zimmermann, 1986).
Live-bearing; litter size up to about 40.
The Convention on International Trade in Endangered Species (CITES) lists all chameleons as threatened. Two reasons for their decline are habitat destruction and the exotic pet trade. Demand for chameleons encourages pet suppliers to take them from the wild and ship them great distances; survival rate may be about 1 in 10, and those that survive arrive malnourished and stressed. Proper care methods for these lizards is not well known, so they may be unknowingly mistreated. Captive breeding has been largely unsuccessful, with the exception of the San Diego Zoo and some private breeders.
CITES: appendix ii
National NatureServe Conservation Status
Rounded National Status Rank: NNA - Not Applicable
Relevance to Humans and Ecosystems
Jackson's chameleons are valuable in the pet trade. They also consume insects.
Its 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. Its specific name 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 χαμαιλέων (khamailéōn), a compound of χαμαί (khamaí) "on the ground" and λέων (léōn) "lion". The Greek word is a calque translating the Akkadian nēš qaqqari, "ground lion".
The three subspecies, including the nominate, are:
- T. j. jacksonii Boulanger, 1896: Jackson's chameleon
- T. j. merumontanus Rand, 1958: dwarf Jackson's chameleon
- T. j. xantholophus Eason, Ferguson & Hebrard, 1988: yellow-crested Jackson's chameleon
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 only known 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 invasive species there. This subspecies has also been introduced to Florida. In Hawaii, they are mainly found 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.
|This section needs additional citations for verification. (November 2010)|
They 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), somewhat reminiscent of the ceratopsid dinosaur genus Triceratops. The females generally have no horns, or traces of the rostral horn (in the subspecies T. j. jacksonii and T. j. merumontanus). The coloring is usually bright green, with some individual animals having traces of blue and yellow, but like all chameleons, they change color quickly depending on mood, health, and temperature.
These are small to medium-sized chameleons. Adult males reach up to 38 cm (15 in) and females up to 25 cm (10 in), but more typical lengths are 15 to 25 cm (6 to 10 in). They have a saw-tooth shaped dorsal ridge and no gullar crest. They attain sexual maturity after five months. The lifespan is variable, with males generally living longer than females.
Jackson's chameleons live primarily on a diet of small insects. It prey on insects, centipedes, isopods, millipedes, spiders, lizards, small birds, and snails in its native habitat.
There is a threat of devastating impact of introduced invasive Jackson's chameleons to native ecosystems in Hawaii. There were found mainly insect in their stomachs: planthoppers Oliarus, grasshoppers Banza, casebearing caterpillars Hyposmocoma, beetles Oodemas, dragonflies Pantala and others. Holland et al. (2010) proved that they also prey on snails in Hawaii. Their prey include land snails Achatinella, Auriculella, Lamellidea, Philonesia, Oxychilus alliarius. They are swallowing whole snails (including shells). Jackson's chameleons introduced to Hawaii are substantial threat to native biodiversity of invertebrates and serious threat especially to endemic species, such as critically endangered O'ahu tree snails (genus Achatinella).
They are less territorial than most species of chameleons. Males will generally assert dominance over each other through color displays and posturing in an attempt to secure mating rights, but usually not to the point of physical fights. Most chameleons are oviparous, but Jackson's chameleon gives birth to live offspring; eight to thirty live young are born after a five- to six-month gestation. The subspecies T. j. merumontanus gives birth to five to ten live young.
In captivity, Jackson's chameleons require high humidity, and are in general very needy of colder temperatures during the night. Too much heat, or excessive humidity, can cause eye infections and upper respiratory infections in these animals. In captivity, the Jackson's chameleon can be expected to live between five and ten years.
- Boulenger, George Albert (1896). Description of a new chameleon from Uganda. Annual Natural History 6 (17). p. 376.
- Spawls, Howell, Drewes, and Ashe (2002). A Field Guide to the Reptiles and Amphibian of East Africa, pp. 227-228. ISBN 0-12-656470-1
- Global Invasive Species Database (2010). Chamaeleo jacksonii (reptile). Retrieved 16 November 2014.
- Liddell, H.G., and R. Scott (1980). Greek-English Lexicon, Abridged Edition. Oxford University Press, Oxford, UK. ISBN 0-19-910207-4.
- Le Berre, François; Richard D. Bartlett (2009). The Chameleon Handbook. Barron's Educational Series. p. 3. ISBN 978-0-7641-4142-3.
- Dictionary.com entry for "chameleon"
- Waring, G.H. (1996) Preliminary Study of the Behavior and Ecologu of Jackson's Chameleon of Maui, Hawaii. Southern Illinois University. Retrieved 11 November 2014.
- "Jackson's chameleon (Chamaeleo jacksonii)". Hawaii Biodiversity Information Network. Retrieved 2013-09-19.
- Holland B. S., Montgomery S. L. & Costello V. (2010). "A reptilian smoking gun: first record of invasive Jackson’s chameleon (Chamaeleo jacksonii) predation on native Hawaiian species". Biodiversity and Conservation 19(5): 1437-1441. doi:10.1007/s10531-009-9773-5.
- Chiaverano L. M. & Holland B. S. (2014). "Impact of an invasive predatory lizard on the endangered Hawaiian tree snail Achatinella mustelina: a threat assessment". Endangered Species Research 24: 115-123, doi:10.3354/esr00589.
- Kraus F. & Preston D. (2012). "Diet of the invasive lizard Chamaeleo jacksonii' (Squamata: Chamaeleonidae) at a wetforest site in Hawaii". Pacific Science 66: 397-404. PDF.
- Exotic Pets section of About.com
Names and Taxonomy
Comments: See Eason et al. (1988) for information on variation in Kenya and description of subspecies (xantholophus).
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