Panther chameleon

The panther chameleon was first described by French naturalist Georges Cuvier in 1829.[3] Its generic name (Furcifer) is derived from the Latin root furci meaning "forked" and refers to the shape of the animal's feet.[4] The specific name pardalis refers to the animals' markings, as it is Latin for "leopard" or "spotted like a panther".[5] 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".[6] This lends to the common English name of "panther chameleon".

Male panther chameleons can grow up to 20 centimetres (7.9 in) in length, panther chameleons have a typical length of around 17 centimetres (6.7 in). Females are smaller, at about half the size. In a form of sexual dimorphism, males are more vibrantly colored than the females. Coloration varies with location, and the different color patterns of panther chameleons are commonly referred to as 'locales', which are named after the geographical location in which they are found. Panther chameleons from the areas of Nosy Be, Ankify, and Ambanja are typically a vibrant blue, and those from Ambilobe, Antsiranana, and Sambava are red, green or orange. The areas of Maroantsetra and Tamatave yield primarily red specimens. Numerous other color phases and patterns occur between and within regions. Females generally remain tan and brown with hints of pink, peach, or bright orange, no matter where they are found, but there are slight differences in patterns and colors among the different color phases.[7]

Like all chameleons, panther chameleons exhibit a specialized arrangement of toes. On each foot, the five toes are fused into a group of two and a group of three, giving the foot a tongs-like appearance. These specialized feet allow the panther chameleon a tight grip on narrow branches. Each toe is equipped with a sharp claw to gain traction on surfaces such as bark when climbing. The claws make it easy to see how many toes are fused into each part of the foot. On the forelimbs, there are two toes on the outer (distal) side of each foot and three on the inside (medial). On the hind legs, the arrangement is reversed: two toes are fused medially and three distally. [8]

Their eyes are the most distinctive among the reptiles and function like a gun turret. The upper and lower eyelids are joined, with only a pinhole large enough for the pupil to see through. They can rotate and focus separately to observe two different objects simultaneously; their eyes move independently from each other. It in effect gives them a full 360-degree arc of vision around their bodies. When prey is located, both eyes can be focused in the same direction, giving sharp stereoscopic vision and depth perception. They have keen eyesight for reptiles, letting them see small insects from a long (5–10-m) distance. Ultraviolet light is part of the visible spectrum for chameleons.

Panther chameleons have very long tongues (sometimes longer than their own body length) which they are capable of rapidly extending out of the mouth. The tongue extends at around 26 body lengths per second. The tongue hits the prey in about 0.0030 sec. The tongue of the chameleon is a complex arrangement of bone, muscle and sinew. At the base of the tongue, a bone is shot forward, giving the tongue the initial momentum it needs to reach the prey quickly. At the tip of this elastic tongue, a muscular, club-like structure covered in thick mucus forms a suction cup.[9] Once the tip sticks to a prey item, it is drawn quickly back into the mouth, where the panther chameleon's strong jaws crush it and it is consumed.

It is a common misconception that chameleons of any kind can change color to match any color of their environments. All chameleons have a natural color range with which they are born, and is dictated by their species. It is affected by temperature, mood, and light. If, for example, the color purple is not within the range of colors to which their particular species can change, then they will never turn purple. Like most species of chameleons, the panther chameleon is very territorial. It spends the majority of its life in isolation, apart from mating sessions. When two males come into contact, they will change color and inflate their bodies, attempting to assert their dominance. Often these battles end at this stage, with the loser retreating, turning drab and dark colors. Occasionally, the displays result in physical combat if neither contender backs down.[3]

Gravid female, Réunion Island

Panther chameleons reach sexual maturity at a minimum age of seven months.[3]

When gravid, or carrying eggs, females turn dark brown or black with orange striping to signify to males they have no intention of mating. The exact coloration and pattern of gravid females varies depending on the color phase of the chameleon. This provides a way to distinguish between locales.[3]

Females usually only live two to three years after laying eggs (between five and eight clutches) because of the stress put on their bodies. Females can lay between 10 and 40 eggs per clutch, depending on the food and nutrient consumption during the period of development. Eggs typically hatch in 240 days.[10]

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  Male, Nosy Be locale
• 
  Female, Réunion
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  Female, Montagne d'Ambre National Park
• 
  Female, Anjajavy Forest

• Ferguson, Gary W.; Gehrmann, William H.; Karsten, Kristopher B. (January 2003). "Do panther chameleons bask to regulate endogenous vitamin D3 production?". Physiological and Biochemical Zoology. 76 (1): 52–59. doi:10.1086/374276. PMID 12695986. S2CID 32215833.
• Dierenfeld, Ellen S.; Norkus, Edward B.; Carroll, Kathryn; Ferguson, Gary W. (27 June 2002). "Carotenoids, vitamin A, and vitamin E concentrations during egg development in panther chameleons (Furcifer pardalis)". Zoo Biology. 21 (3): 295–303. doi:10.1002/zoo.10039.