The vast majority of animals with ocular media, including fish, amphibians, insects and other invertebrates, reptiles, birds and some mammals are capable of seeing ultraviolet light. Goldfish, mantis shrimp, butterflies and eagles are a few examples, while hedgehogs are one of the most UV-sensitive mammals.
Prior to several studies published in 2014, the nature of UV-sensitive mechanisms in animals, particularly mammals, was unknown. Most animals that can see into the ultraviolet spectrum possess ocular lenses that let UV light into the eye where a pigment sensitive to UV absorbs it. However, even without these pigments, all examined photoreceptors in the animal kingdom exhibit some sensitivity to UV radiation if this light reaches them. Cats, dogs, red pandas, cattle, reindeer and okapi are a few of the mammals that a study proved could, at least partially, see UV light.