Ecology, Biogeography & Conservation Article
by James M. Ko

This article provides general observations of habitats where Jackson's chameleons dwell on the island of Oahu, Hawaii. I do not impart specific details on the exact locations where Jacksoni can be found. Collectors with an understanding of life in the field will find enough information to help you (should you decide to visit and collect samples of Jacksoni for your private collection).

It has been nearly 30 years since the Jackson's chameleon were first released into the hills of the Ko'olau. During this time, I have been fortunate to gain knowledge of the animal and its characteristics in nature, and to learn about the biome which supports the Jackson's chameleon's life style. Through this, I have gained a greater appreciation for the natural sciences of the earth and an even greater appreciation for natural life as it occurs in Hawaii. The past two decades have seen dramatic changes in both the popularity of Jackson's chameleons as a "pet trade item" and the populations of Jackson's chameleons that have established themselves throughout Hawaii. I am constantly mindful of what I have seen, and accept the fact that it is within human nature to:

  1. Be self-serving and/or greedy.
  2. Haul animals out by the droves.
  3. Ruin habitat for other wildlife.
  4. Sell animals to the uneducated, thereby causing the death of the animals.
  5. Break the law.

It would be simplistic to explain that Hawaii is a "tropical paradise" which provides all the requirements to sustain the Jackson's lifestyle. But if one truly wants to learn why or where Jackson's chameleons have managed to establish themselves, success comes with understanding the precursors of Hawaiiana from an ecological perspective.


Unlike many areas of the continental United States, the climate in the Hawaiian Islands can be uniquely variable from one location to the next. At the same time, weather conditions will remain consistent to each particular area, year round. To put this statement into perspective, consider that the lower Manoa valley received an annual precipitation of 68.9 inches during 1997. A five minute drive by car to the upper Manoa valley, with an annual precipitation of 162.7 inches in 1997, reveals how two locations in close proximity to each other can differ in climate, yet maintain its own stable weather patterns during any given period (see Precipitation Table).

To help understand why this occurs, one must understand the pivotal connection between Oahu's high mountain range (Ko'olau) and Oahu's abundant rainfall. The crest of the central Ko'olau range overlooks the island of Oahu and receives over 250 inches of rainfall annually.


Moisture from the ocean is driven up against the mountains, where it rises, cools, forms clouds, and then, falls as rain. It is estimated that an average of about two billion gallons of rain fall on Oahu during a typical year. As rain soaks into the slopes of the Ko'olau and slowly makes its way down through the porous volcanic rock, it ends up deep within the basal aquifer system of Oahu. It is within this relationship that various ecological niches develop and diverse life forms evolve and flourish.

The Hawaiian Islands were initially formed when shield volcanoes rose up from the ocean floor and created gently sloping, symmetrical mountains.

These mountains slope into numerous valleys, and have been shaped by millions of years of erosion. In general, the deepest valleys begin where rainfall is heaviest. The wettest areas of Hawaii are often teeming with vegetation, and in some areas, overgrowth of the topography, as well as weather conditions make it inaccessible to man.


Below the crest of the volcanic mountain, many of the valleys slope into rainforest entrenchments which support unique microclimates and ecosystems. These elevations can range from 1,200 & 2,000 feet depending upon the location, with temperature conditions 2-4 degrees F cooler than lower level areas. Moisture and vegetation also differ greatly as you ascend from lower to higher areas; from thorny shrubs, kiawe (Prosopis pallida) and kukui (candle nut tree), to acacia, eucalyptus, coffee, strawberry guava (Psidium cattleianum), and carpeted by dense, ferns, vines, etc.

The amount of rainfall in an area varies dramatically depending on which side of a mountain one happens to be. In general, trade winds blow from the northeast, carrying moisture to the windward slopes and travel over the Ko'olau range to the rest of the island of Oahu. Among some of the trails leading to the rainforest, hau, ohia ai, guava trees, and bamboo are common. Nocturnal temperatures can drop 4-8 degrees F depending on location and time of year. As a general rule of thumb, hikers can experience temperature changes between 3-5 degrees Fahrenheit for every 1,000 feet of elevation.

Jacksoni found in the rainforest areas appear to be larger, healthier, and more robust compared to those found in lower levels of the valley basin. A number of factors contributing to this differential growth will be described later in this article. In general, the coloration and markings appear to be influenced by the flora/fauna, food source, and sunlight surrounding them. Young adult animals from the rainforest habitats tend to be lighter in color (bright yellow/blue, green) compared to animals found in the basin, which have darker markings (dark green, brown, red, etc.).

High Elevation
Young Female from Rainforest
Yearling Male
From Rainforest
Trail in Valley Basin

Large Mature Female
from Basin

Large Male from Valley Basin

One interesting physical observation of "some" Jacksoni subtly appears in the dorsal area. Picture 1 depicts a "double ridge" in the dorsal crest of one male Jacksoni, versus a common single ridge found on most animals in picture 2. There is not enough evidence to suggest that this is "area specific" or whether it might be due to directional selection or genetic drift.

Double Ridge

Single Ridge

Additional observation by some Jacksoni collectors in Hawaii finds adult animals in the rainforest habitats to be reticent in personality. If confirmed, this difference may be due to less frequent visits by man to the higher elevations as compared to lower elevation areas where trails are more readily accessible to the casual hiker, mountain bicyclist etc. In general, personal observations of jacksonii dwelling in thick, dense habitats, have found them to be shier than those found in less abundant foliage, regardless of habitat elevation.

Many of the rainforest habitats are actually protected by broad State laws, which prohibit the removal or harm of the natural flora/fauna etc. Thus, simply trekking through a rainforest with a machete to find Jackson's chameleons (regardless of whether one has a permit) may be illegal. Interestingly, during earlier years, when Jackson's chameleons had not yet been acknowledged by the State of Hawaii (pre -1990), it was illegal for anyone to own these animals locally.

Valley Basin

The basin areas are generally more accessible for collecting Jackson's chameleons, regardless of the valley (i.e. Kaneohe/Kailua, Kahaluu, Nuuanu, Tantalus, Kalihi, Palolo, Moanalua, Aiea, and the Leeward areas etc.). During the mid - late 1980's, basin animals were very robust and plentiful. This was, in part, due to seeding efforts by local herpers and black market entrepreneurs in the late 1970's to early 1980's, and more importantly, a demand for jacksonii, which had not yet peaked.

While early generations of jacksonii populations became established and colonized many new basin habitats, changes in topography and the demand for Jacksoni over the years, have impeded their genetic diversity. Residential development, construction to prevent rockslides, completion of the H2 and H3 freeway, clearing of fauna by municipal govt., and leptospirosis in certain natural streams, were some of the significant changes, which adversely affected the food sources for jacksonii in a number of habitat areas.

In addition to changes in the topography, competition with other species that were affected and/or displaced with jacksonii further complicated the original niche of the ecosystem. During the early 1990's, it was easy to find jacksonii in numerous basin areas (in part, due to their displacement) and it fashioned the perception that there was an over abundance of jacksonii.

As perception of the over abundance circulated, some of the most vocal chameleon enthusiasts on the Internet were raising issue with the impact that jacksonii were having on the environment. This erroneous perception only supported the increasing demand for Jackson's chameleons during the 1990's and encouraged a new breed of entrepreneur whose only "cause" was to meet market demand. The sight of off-road vehicles tearing up the street with fog lights and stereos blasting, shining small craft spotlights up into the trees, seemed to become commonplace in many areas.

The result of these changes has affected the genetic diversity of lower basin jacksonii, and legitimate reductions are reported in a number of Oahu's basin areas. In addition, smaller pockets of "young populations" seem more frequent as opposed to mature populations in well-established areas. This is reminiscent of early-seeding years when local herpers began introducing jacksonii to other areas of the island. This is also true of some of the outer island populations which are Òless matureÓ and which were founded by a very small breeding population which lacked genetic diversity. These young populations need time to increase their genetic variability and adapt to the different environmental schemes that have been forced into their ecosystem.

There are noticeable differences between young jacksonii populations compared to those found in more mature-established areas (indicative of the upper rainforest). Jacksoni from young populations tend to display weaker physical characteristics (e.g. poor horn/skeletal development, narrower helmet crests, slighter built limbs and muscularity, and gaunt hip development).

With the recent advent of the DLNR's export curtailment, populations of jacksonii found in lower basin areas will receive a reprieve. However, considering the disturbances imposed upon the ecosystem, the rate of population increase may not be as prolific as it once was over a decade ago in the 1980s. The DLNR's decision to eliminate further introduction of illegal species to Hawaii by prohibiting export of established animals raises some degree of uncertainty. Discouraging legitimate avenues of revenue instead of supporting a viable industry may actually perpetuate black market activity in an already confused market.

Range Dwelling
"Look to the biome, understand its process of life, and use this knowledge to your advantage." JP

While reports of fewer jacksonii are substantiated in a number of basin areas, many of Oahu's other basins still support liberal populations. I can't begin to count the number of times I have been asked to share specific locations where jacksonii can be found. Hence, in this section, a brief narrative will aid in your quest to find jacksonii on the island of Oahu.

If one considers the process of life as it occurs in nature, and understands the basic principles of food and shelter as requisites for all life forms, prudent thought will lead to finding jacksonii during any given period in a calendar year.

Unlike some previous observations of Jackson's chameleons which suggest that they normally remain within the same tree/shrub, etc., observations in Hawaii indicate that they actually maintain a "home range" amidst flora which support their diverse behavioral requirements. In many areas of the Hawaiian habitat (regardless of rainforest or basin), a single tree does not provide enough diversity to meet the needs of a Jackson's chameleon's lifestyle. During the course of a year, and depending upon the location, Jacksoni often maintain patterns of "range dwelling" (for the lack of a better term), relocating from one tree/area to another, and then back again etc. This range dwelling appears to be influenced by such factors as the quality or density in the habitat, immediacy of the food source, reproduction habits, and weather conditions.

For example, during certain times of the year, when various species of insects such as the katydids are plentiful, it is not uncommon to observe jacksonii residing in structures that are closer to the biome floor. Vine-like flora such as Koali 'awa (morning glory)", aka 'awa, or thick-stemmed plants which grow out from the sides of trees, such as large monsteras, are a few examples of flora that grow near these areas.

During periods of inclement weather, such as a heavy rainstorm, nighttime observations of adult jacksonii find them sleeping deep in dense foliage. Yet, on warm, muggy evenings, when humidity is trapped within the valley, they tend to migrate to more "spatial and leafy" flora, and are often found higher up in the tree, closer to the night air.

It is not uncommon for male jacksonii to leave their immediate flora habitat in favor of breeding with a female sighted in another area. Upon completion of copulation, the male may stake claim to the habitat, defending his territory against other rogue jacksonii. Should the incumbent lose during ritual battles of horn locking, the male often returns to the initial flora habitat from which he came.

In many instances, it is the female jacksonii that actually leave the habitat upon completion of copulation. Observations of pregnant females (ready to drop) find them frequently favoring flora structures that are dense and weedy (Lantana, Kiawe, and various creepers which extend from branches of large trees). In general, the warmer months of Oahu tend to produce the largest brood sizes and females tend to gravitate towards lower levels of the arboreal habitat to give birth. Following parturition, the female jacksonii will then migrate back to the higher levels in the flora structure.

Neonates and young juveniles are often found in areas much similar to that of pregnant females. These young tend to remain in lower structures due to proximity of food, as well as protection from predation by larger species (including other jacksonii). When deciduous fruit trees are abundant, the young jacksonii can often be observed in flora surrounding the perimeter of a tree, feeding on insects that are attracted by fruit-fallings on the forest floor. Nocturnal observations also find young jacksonii favoring dense overgrowth (i.e. Lilikoi, Koa Haole) around the perimeter of the main stem where much larger species dwell.

As the young jacksonii mature, they may migrate to habitats that are not as dense in flora, but provide enough plant life to afford vantage points to feed upon their prey. For example, in some areas of Oahu's topography, valley walls gently slope to form cul-de-sacs, where small trees grow on the sides of the mountain. Young Jacksoni favor these areas as they overlook vegetation in the cul-de-sac floor, permitting accessibility to food and water and shelter away from much larger species in their bionetwork.

Closing Thoughts
As chameleon enthusiasts, we have learned to embrace the science of chameleon husbandry, largely due to the unselfish work of many individuals. Scientific investigation, naturalistic observation, creative husbandry practices, and even failures, have all contributed to the growing body of knowledge necessary for successful care of captive chameleons. Thoughts into a chameleon's propensity for "wanderlust" seem to support the observations of range dwelling, in which jacksonii seek out new areas to support their biological needs (food, shelter, or propagation).

I recognize that the brief narrative of range dwelling "might" increase the animal's susceptibility to human exploitation. But to the more seasoned Jackson's chameleon collectors in Hawaii, I propose that the years of exploitation we have already seen should encourage us to help educate others and establish principles for the collection of animals from the field.

Responsible field management is a global problem. To continue to guard our "understanding" of the Jacksoni in Hawaii is akin to holding back the wealth of knowledge which we have already accumulated. It has been my privilege to help disseminate some of this knowledge and I thank you for the opportunity.

Field considerations:

  1. Acquire the DLNR permit and check with authorities for proper transport.
  2. Safety first. Stay on the trail if you are unfamiliar with the area.
  3. Leave hapai (pregnant) females in the field.
  4. Leave keiki (young) neonates and sub-adult animals or anything under 3 inches svl
  5. Chameleons have scales, but they don't have gills and fins — what's with the net?
  6. Paul Bunyon was a big guy — that doesn't mean you have to chop down the tree.
  7. Remember Smokey the Bear? Take your butts, bottles, and garbage somewhere else.
  8. Keep the market clean.

Best Wishes and Aloha,
James M. Ko (JP)
Precipitation Table

Credits, Acknowledgements, and Thanks to:
Messieurs Don Wells, Ed Pollak, Bill Strand, Kyle Chang, and Ms. Susan James who honored me by asking me to write this article.
The members of the ADCHAM list, for the knowledge and wealth of exchange.
Mr. Jerry Tresser for his confirmation.
Aloha to Bonnie Keller and the rest of PCF.
Messieurs Aaron Miyamoto and Al Balderama, for their friendship, skill, and appreciation of herps in Hawaii.
Hawaii Herpetological Society É may you rise again like the phoenix.
The Gornichec family (Mrs. G., Frank, Bob), and Buddy of Modern Pet Center, Honolulu, Hawaii.
Randy, Darrin, and Daryl, who wish to remain anonymous.
Ms. Gina Wong (State of Hawaii Department of Agriculture, Statistician).
Dr. Eric Ako, DVM.
Mrs. Margaret Lee, FattyMoKo, and the staff of Playmate Kindergarten, DCC & Grade School, Ltd.
I dedicate this article to the memory of my sister, Monica, who will always be with us.
References available upon request.

This page last updated on: Sunday, April 7, 2002

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