On your next visit through the outdoor Madagascar section of the DWA, take a minute to stop and listen. Chances are you will hear someone referencing one of the following: “that paint commercial”, “Pascal”, “Rango”, and/or car insurance. Two recent films have had prominent chameleon characters – “Pascal” acting as Rapunzel’s sidekick in the Disney film Tangled, while a lizard named “Rango” serves as the main character in the Paramount Pictures animation by the same name. On the small screen, Valspar Paint has recently adopted a pair of indecisive chameleons trying out various color options, while a day gecko has served as the face of GEICO Insurance for years. It is for good reason that these specific animals have become part of our pop culture. They hail from exotic locations and have a range of unique and fascinating adaptations. Unfortunately, it becomes difficult to distinguish what we consider to be fact from fiction. For example, I don’t think anyone believes that day geckos run around talking, wearing cowboy hats, or drinking coffee; however, many people are surprised to learn that chameleons do not possess the ability to change their color to match their surroundings.
For most people, this fact tends to take a moment or two to absorb. In this instance, however, this misconception seems to be the result of misinterpreted information rather than a colorful imagination – pun intended. Chameleons do have the ability to change color, but they usually have a narrow range which is pre-determined by their specific species. These changes are usually the result of factors within their environment rather than the environment itself. All chameleons will have a standard coloration that they will display while they are at rest—usually perched on a branch or vine surrounded by vegetation. Temperature, stress, or hormonal changes are among the reasons why you might witness a color change. An anger or stress response may be witnessed while initially handling an animal or removing it from its enclosure – the change is usually instant, lasts for a short time, and then returns to “normal”. Being solitary animals, stress and the resulting color changes can also occur when two chameleons, especially males, come into visual contact with each other. Hormonal color changes, such as those indicating that a female has developing eggs, may last days or weeks.
We have two different chameleon species on display here at the DWA. The Meller’s chameleon (Chamaeleo melleri) is found on the African mainland (Tanzania, Malawi) and is one of the largest chameleon species, with individuals weighing slightly over one pound and measuring nearly two feet in length. An impressive fact is that their tongues can be up to twenty inches long- nearly the total length of the animal. This long, sticky tongue acts like a catapult, quickly capturing various insects, other reptiles, and even small birds. To help hone in on their prey, chameleons have eyes that can pivot and focus independently, allowing them to see two images simultaneously.
The island of Madagascar is home to approximately half of the world’s chameleon species, including the Panther chameleons (Furcifer pardalis) which we also have on display. There are several different color morphs, or locales, of Panther chameleons, which are identified and named to indicate where that specific lizard originated. We have two localities represented in our collection – the Nosy Be which is blue, and the Ambilobe which is green. Males and females are dimorphic- that’s to say they physically look very different. A mature female Panther chameleon is about half the size of a male and lacks the vibrant coloration associated with the males of the species. To help them move around their arboreal environment there are two physical adaptations worthy of mention. The feet of the chameleons have five digits which are grouped with two on one side and three on the other. This modified grip, in combination with sharp nails on each digit, allows them to successfully move through trees and other vegetation. In addition to their four limbs, they also have a prehensile tail which they can use as a “fifth limb” to increase stability while at rest, or even hang by, while reaching for another branch.
While lacking the ability to change color or hang by their tails, the day geckos of Madagascar have their own unique adaptations. The Aquarium has two species of day geckos on display – the Giant Madagascar day gecko (Phelsuma madagascariensis grandis) and the Gold dust day gecko (Phelsuma laticauda). Unlike most gecko species which are nocturnal, as their name implies, the day geckos are active during the day. They feed on insects as well as the occasional fruit or nectar. Where the chameleons have feet modified for gripping, the day geckos have feet modified for sticking. Noted for their ability to effortlessly move across flat, smooth surfaces, gecko locomotion and adhesion have been studied not only by biologists but by engineers and others hoping to replicate this impressive ability. This adhesive characteristic is the result of millions of microscopic setae, essentially tiny hairs, on their feet which allow them to grip even the smoothest surfaces with a force far greater than is required to keep their body in place.
Slightly less impressive, but equally important for the life of a gecko, is a self-defense mechanism known as autotomy, or self-amputation. If you’ve ever tried to grab a gecko you may have witnessed this equally disturbing and fascinating phenomenon. In response to being grabbed, a gecko has the ability to amputate all or part of its tail. The hope is that this will confuse or distract a predator, giving the gecko time to escape. What’s even more impressive is that the tail will then begin to regenerate itself from the point of amputation, and overtime will be completely restored.
The lizards of Madagascar aren’t the only lizards at the DWA with unique characteristics and adaptations. In the Rainforest you will find the Basilisk lizards (Basiliscus plumifrons and B. vittatus) that are known for their ability to run across the surface of the water, and the Caiman lizards (Dracaena guianensis), with jaws powerful enough to easily crush large snail shells. In Mundo Maya you’ll find the Beaded lizards (Heloderma horridum) which are one of only a handful of venomous lizards. While they all may not be Hollywood material, with nearly 5,000 lizard species throughout the world, there is bound to be something to interest everyone!