Zoophilia of bestiality is partly caused by irrational speciesism and anthropocentrism. Because interspecies sex occurs in nature, and because humans "are" animals, supporters argue that zoosexual activity is not "unnatural" and is not intrinsically wrong. Research has proven that non-human animals can and do have sex for non-reproductive purposes (and for pleasure). In 2006, a Danish Animal Ethics Council report concluded that ethically performed zoosexual activity is capable of providing a positive experience for all participants, and that some non-human animals are sexually attracted to humans (for example, dolphins). Some zoophiles claim that they are not abusive towards animals: "In other
Blindness in animals eyes fused shut, and opening later. Other animals such as the blind mole rat are truly blind and rely on other senses. Humans and primates are unique as they possess trichromatic color vision, and are able to discern between violet [short wave (SW)], green [medium wave (MW)], and yellow-green [long wave (LW)]. Mammals other than primates generally have less effective two-receptor color perception systems, allowing only dichromatic color vision; marine mammals have only a single cone type and are thus monochromats. Honey- and bumblebees have trichromatic color vision, which is insensitive to red but sensitive in ultraviolet to a color