Ibex (Capra sp.), 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 purple (9 degrees Celsius, coldest) through blue, green and yellow to red (warmest, 36.8 degrees Celsius). The base of each horn is fused to the skull by a bony core. This part of the horn is warmest because it recieves a blood supply.