The statement provided in the question is FALSE. Gamma rays are indeed a form of electromagnetic radiation, like light, microwaves, and X-rays, but their defining characteristic is not primarily defined by their wavelength in the range of $10^{-6}$ to $10^{-5}$ cm. Instead, gamma rays are on the extreme high-energy end of the electromagnetic spectrum and are characterized by their very short wavelengths and high frequency.

Specifically, gamma rays have wavelengths less than about $10^{-10}$ meters (or 0.1 nanometers). This means they are on the order of picometers ($10^{-12}$ meters) and even shorter, which is much shorter than the wavelength range mentioned in the question. Gamma rays typically come from nuclear reactions, radioactive decay, or processes occurring in celestial objects under extreme conditions, such as supernova explosions or the regions around black holes.