Herpetoculture is the keeping of live reptiles and amphibians in captivity, whether as a hobby or as a commercial breeding operation. "Herps" is an informal term for both reptiles and amphibians, shortened from the scientific umbrella term “herptiles”. It is undertaken by people of all ages and from all walks of life, including career herpetologists, professional reptile or amphibian breeders, and casual hobbyists. The origin of the word "herpetoculture" is credited to Tom Huff, who devised the word to distinguish what he, as a self-described "herpetoculturist", was doing—working to keeping reptiles and amphibians alive and healthy—from what herpetologists of that era were generally doing, namely, collecting specimens for preservation in museum collections. The word itself comes from the Greek language origin , which means "to creep". Though traditional glass aquariums and terrariums are still widely used, in recent years glass and fiberglass cages designed specifically for herps have become more widely available. Many herpetoculturists prefer these newer enclosures as they come in larger sizes, are more secure, can be stacked, and are more easily modified to included heat and humidity sources. At one time it was commonly accepted to keep multiple creatures in a small enclosure; however, current cage size recommendations discourage this. These size recommendations differ depending on the species and its natural environment. As reptiles are cold blooded they generally need to be kept in climate-controlled enclosures, especially when kept in regions further away from the equator. A standard enclosure usually incorporates a thermostat and a heat emitter; usually a heating pad, heat tape or an incandescent light bulb. Hot rocks can be used, but as a secondary heat source, as they often provide uneven heating. Some reptiles also require some form of Ultraviolet radiation which can be provided through a UV bulb. The lighting can be set to a timer to simulate a day/night cycle.