Namaqua Chameleon - MS

NAMAQUA CHAMELEON'S THERMOREGULATION

The Namaqua chameleon is a ground-living species, found in western desert regions of Namibia, South Africa and Angola.  The namaqua chameleons therefore aim to heat up as quickly as possible  in the morning as this is   the only time of the day it is cool enough for them to be active. Most ectotherms bask in the heat to warm and go into the shade to cool down as a way to maintain body temperature; however, Namaqua chameleons take this several steps further.

 Firstly, they bask in the sun with their body positioned to be on the side towards the sun, hence exposing the maximum amount of surface area to the heat source. Additionally, the chameleon will darken the side exposed to the heat source to maximise heat absorption as darker colours are better absorbers of thermal energy. They also lighten the opposite side in order to retain heat once absorbed, as light surfaces are poor emitters of heat. This lightening of the side in shade also acts as camouflage as any predator looking from below the chameleon would find the lighter side harder to see. They also dig holes in the desert to aid the process of thermoregulation.

 The chameleons also alter the shape of their body as they have hinged ribs which allow them to flatten their body, thus increasing the surface area of the side exposed to the heat source, allowing them to heat up at a faster pace.



Chameleons also have the ability to alter their blood flow rate as their heart beats significantly faster when warming up than when cooling down. This results in the increased heat transfer between the warm surface and the cool core. Once the Namaqua chameleon has warmed up its internal temperature, the heart rate slows down to reduce heat loss and the chameleon begins the daily task of hunting for food.

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<p class="ecxmsonormal" style="margin: 0cm 0cm 0pt;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10pt;">Reaching an optimal temperature is important for Namaqua chameleons as it directly influences their ability to hunt, capture and digest prey as the chameleons move quicker, are more accurate with their tongue and have faster and more efficient digestion when at their optimal temperature.

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