When the Namaqua chameleon changes color, it's not just defensive camouflage to avoid predators. This tiny desert reptile regulates its body temperature by changing its hue, getting darker to absorb heat in the morning and lighter to reflect the sun's rays in the hot afternoon. This particular chameleon thoroughly charmed photographer Martin Gregus Jr, with its precise, mesmerizing movements as he filmed it in the NamibRand Nature Reserve in Namibia. | National Geographic