In terms of senses, the Lesser Antillean iguana (Iguana delicatissima) has excellent daytime vision and a highly developed taste - thanks to the multiple taste buds of its tongue - but poor hearing compensated by its sensitivity to vibrations. Its double-cone cells allow it good color vision up to ultraviolet, an ability particularly useful to absorb enough UVA and UVB to produce vitamin D3 in sunlight. It can also distinguish shapes and movements over long distances. The reptile's vomeronasal organ, or Jacobson's organ, which it feeds by repeatedly deploying its tongue, allows it to analyze the molecules present in its environment more precisely than by its sense of smell. Its nasal orifice is common to the sense of smell and this organ. A photosensitive third eye, called pineal or parietal eye, is located on top of its skull. It enables the iguana to perceive the intensity of light, a decisive factor in the ecology of this poikilothermic reptile capable of varying the color of its skin and its heart rate to maintain its body temperature.