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 mapLocations where this alien species has been
reported as established in California at one time: Red

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

Alien Herps in California

observation link

This is an alien species that 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 or by clicking on the links below.

Orange County
Orange County
Orange County
San Diego County
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..)

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)

Full Species Range Map
Origin of Morro Bay Population
I have received a description of the origin of this introduced population of lizards in Morro Bay from two independant sources.
Both state that the lizards were released in 1981 by California Department of Fish and Game employees when they left the door open to a chameleon cage during a raid on a suspect in Morro Bay. It is assumed that the employees did not see the lizards in the cage and ten chameleons accidentally escaped into the wild.
After dispersing, the lizards eventually began breeding.

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."

- refers to Sir Frederick John Jackson (1859-1929) an English naturalist and ornithologist who did much exploring in Kenya, where Jackson's Chameleons 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.

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 August 2019 California Natural Diversity Database (CNDDB) Special Animals List and the CNDDB 2019 Endangered and Threatened Animals List, both of which are published by the California Department of Fish and Wildlife.

The status listings here might not be the most current. Check the CDFW CNDDB website to see if there are more current lists:

If no status is listed here, the animal is not included on either CDFW CNDDB 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 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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