A Guide to the Amphibians
and Reptiles of California

Jackson's Chameleon - Trioceros jacksonii

Boulanger, 1896

(= Chamaeleo jacksonii. Also: Jackson's Horned Chameleon; Kikuyu Three-Horned Chameleon)
Click on a picture for a larger view
range mapRed: Locations where this non-native species has been
reported as established in California

If you see a lizard that looks like this living in the wild
anywhere in California please contact me
and send a picture if you can.

Click on the map for a topographical view

Map with California County Names

List of Non-Native Reptiles and Amphibians
Established in California

observation link

This species has been introduced into California. It is not a native species.

Yellow-crested Jackson's Chameleon Yellow-crested Jackson's Chameleon
Yellow-crested Jackson's Chameleon
Adult male, Morro Bay, San Luis Obispo county © Gary Nafis,
specimen courtesy of Steven Boone & Joe Cirone
Adult female, Morro Bay, San Luis Obispo county © Gary Nafis,
specimen courtesy of Steven Boone & Joe Cirone
Yellow-crested Jackson's Chameleon
More pictures of Jackson's Chameleons found in California can be seen on the 
H. E. R. P. database and on iNaturalist.
Adult female, Morro Bay. © Emily Taylor      
Wild Jackson's Chameleon From Hawaii
Yellow-crested Jackson's Chameleon Yellow-crested Jackson's Chameleon Yellow-crested Jackson's Chameleon Yellow-crested Jackson's Chameleon
Adult female, 1,600 ft., Maui, Hawaii.
Notice the color variation in these pictures of the same lizard taken within 20 minutes, with the first on the left and the last on the right.
Yellow-crested Jackson's Chameleon Habitat Yellow-crested Jackson's Chameleon Habitat    
A foggy summer morning in Morro Bay, San Luis Obispo County Chameleons have been found on this property and similar residential areas around Morro Bay.    
Description - based primarily on McKeown, 1996
Average snout-to-vent length 4 3/4 - 5 inches ( 12.1 - 12.7 cm).
Average total length is 10 inches (25.4 cm).

A large, thick-bodied lizard, able to rapidly change color.
Large eyes are able to move independently of each other, and are set on turrets, allowing them to move around in a circle which enables a chameleon to see in any direction.
The tail is prehensile, aiding a lizard in climbing.
When not in use, the tail is coiled.
The tongue is hollow and extremely long - more than the length of the entire body.
It is rapidly shout out of the mouth by muscular contractions to grab at prey with its sticky tip.
Color and Pattern
Coloring includes yellow, blue, brown, gray, charcoal, black, and many shades of green.
Male / Female Differences
Males and females are different in appearance.
Males have three horn-like projections at the front of the head.
Females lack these horns.

Life History and Behavior

Arboreal - living in trees and bushes.
Opposable toes on all four feet allow sure footing, and a prehensile tail aids in climbing.
Changes color in response to interaction with other chameleons, light, temperature, response to threats, and activity.
Males use horns to spar for territory or breeding rights.
The losing male is pushed off a limb and forced to retreat.
Chameleons will flatten the body or make it appear thinner to hide by blending in with the foliage.
Diet and Feeding
Eats a variety of small invertebrates.
A male will approach a female, bob his head side to side, and show yellow and blue coloring.
The female will indicate her readiness to mate by turning solid green.
If not, she will show stress coloring, including large areas of black, and she will hiss and bite.
Young are born live, encased in a membrane, after a 5 to 6 month gestation period.
During birth, the female sits at an elevated location and drops each newborn to the ground which stimulates it to emerge from its membrane.
Anywhere from 5 - 50 young are born.
Young are ready to feed within hours of birth.

In California, this lizard seems to have adapted to vegetation around human settlements along the coast where the combination of fog and sunshine provide it with the necessary temperature and moisture requirements.
It appears that this lizard is in danger of dessication from dry environments.

Geographical Range
Native to humid cool areas of Kenya and Tanzania in East Africa, especially at altitudes of over 3,000 meters (9842 ft..)

Range in California

Established in San Luis Obispo and Orange Counties. (May not be established in both locations now.)
Possibly established in San Diego and Los Angeles Counties.
Locations include Morro Bay, Laguna Beach, and possibly the Palos Verde Peninsula and Balboa Park.
(McKeown, Bulletin of the Chicago Herpetologial Society 32:101. 1997)

Origin of the Morro Bay Population

I have received personal communications regarding the origin of the established population of non-native Jacksons chameleons in Morro Bay from more than one source, with the same facts, so I believe the story is accurate. The chameleons were released by California Department of Fish and Game employees when they left the door open to a chameleon cage during a raid on a man suspected of selling prohibited reptiles in Morro Bay in 1981. It is assumed that the employees did not see the lizards in the cage and 10 chameleons accidentally escaped into the wild. It is not known how many male and how many female chameleons escaped. After dispersing they found the habitat favorable and eventually began breeding.

Full Species Range Map
Notes on Taxonomy
Formerly known as Chamaeleo jacksonii.
Trioceros was previously considered a subgenus of the genus Chamaeleo until 2009 when it was elevated to full genus level. (Wickipedia 6/18)

Conservation Issues  (Conservation Status)
It is not evident how competition from this introduced species impacts native species, but the spread of this or any non-native species should be discouraged.
Family Chamaeleonidae Chameleons Gray, 1825
Genus Trioceros Chameleons Swainson, 1839

jacksonii Jackson's Chameleon Boulanger, 1896
Original Description
Chamaeleo jacksonii   Boulenger, 1896 : Jackson's Chameleon

Meaning of the Scientific Name
The name "chameleon" means, "Earth lion" and is derived from the Greek words "chamai" (on the ground, on the earth) and "leon" (lion).
(From Wikipedia)

- "three horns" from Greek - "tri" = "three" and "keras" = "horns."


First described by Belgian-British zoologist George Albert Boulenger in 1896, the specific name "Triceros jacksonii" and the common name "Jackson's Chameleon" honor Frederick John Jackson (1859-1929) an English explorer, ornithologist, and the Governor of Kenya a the time where the chameleon originated.
Biographical detail can be found in 'Whose Bird?' by Bo Beolens & Michael Watkins, 2003, Christopher Helm, London (The authors are working on a similar eponym dictionary for reptiles and amphibians that will be published in approximately 2011.)

Alternate Names
Chamaeleo jacksonii - Jackson's Chameleon

Jackson's Horned Chameleon
Kikuyu Three-Horned Chameleon

Some sources identify these introduced lizards as the subspecies:
Yellow-crested Jackson's Chameleon - Chamaeleo jacksonii xantholophus Eason, Ferguson & Hebrard 1988

Related or Similar California Lizards

More Information and References
California Department of Fish and Wildlife

Stebbins, Robert C., and McGinnis, Samuel M.  Field Guide to Amphibians and Reptiles of California: Revised Edition (California Natural History Guides) University of California Press, 2012.

Stebbins, Robert C. California Amphibians and Reptiles. The University of California Press, 1972.

Flaxington, William C. Amphibians and Reptiles of California: Field Observations, Distribution, and Natural History. Fieldnotes Press, Anaheim, California, 2021.

Stebbins, Robert C. A Field Guide to Western Reptiles and Amphibians. 3rd Edition. Houghton Mifflin, 2003.

McKeown, Sean. A Field Guide to Reptiles and Amphibians in the Hawaiian Islands. Diamond Head Publishing, Inc. 1996.

Conservation Status

The following conservation status listings for this animal are taken from the January 2024 State of California Special Animals List and the January 2024 Federally Listed Endangered and Threatened Animals of California list (unless indicated otherwise below.) Both lists are produced by multiple agencies every year, and sometimes more than once per year, so the conservation status listing information found below might not be from the most recent lists. To make sure you are seeing the most recent listings, go to this California Department of Fish and Wildlife web page where you can search for and download both lists:

A detailed explanation of the meaning of the status listing symbols can be found at the beginning of the two lists. For quick reference, I have included them on my Special Status Information page.

If no status is listed here, the animal is not included on either list. This most likely indicates that there are no serious conservation concerns for the animal. To find out more about an animal's status you can also go to the NatureServe and IUCN websites to check their rankings.

This animal is not included on the Special Animals List, which indicates that there are no significant conservation concerns for it in California.

Organization Status Listing  Notes
NatureServe Global Ranking
NatureServe State Ranking
U.S. Endangered Species Act (ESA) None
California Endangered Species Act (CESA) None
California Department of Fish and Wildlife None
Bureau of Land Management None
USDA Forest Service None


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