Elephant, thermogram. A thermogram shows variation in temperature on the surface of an object, measured by the long-wave infrared radiation it emits. The temperature scale is colour-coded and runs from black (21.5 degrees Celsius, coldest) through blue, purple and red to light yellow (warmest, 34.3 degrees Celsius). The elephant has recently defecated, and the temperature of its excrement (lower right) is much warmer than the surrounding area.