There are a myriad of visual signals ranging from pigmentation to postural displays. Pigmentations are one of the ways animals can display colour. Melanin is a pigment that produces a range of colours from black to brown. Prairie warbler males deposit melanin in their wings to strengthen them, and females use these melanin stripes as an indication of the male’s health. Carotenoids are an orange pigment that animals acquire from plants. Pterins are a red pigment produced by lizards, such as in anoles’ dulaps. Porphyrins are pigments with multiple qualities. Firstly, in the visual spectrum, porphyrins produce browns, reds, and greens. Secondly, porphyrins under UV light produce a bright red colouration. Porphyrins are a good example of the fact that animals have their own way of perceiving the world, some can detect UV and so would see porphyrins differently than we do. Another way animals can produce colouration is through structure. Hummingbirds’ iridescent plumage is the result of refraction in their feathers. The microscopic structures in their feathers act as prisms that reflect only certain wavelengths of light, resulting in shiny, metallic colours. Blue jays don’t have blue pigment in their fathers, but have microscopic air bubbles that refract light to produce different shades of blue. Animals also produce visual signals through posture, gestures, displays, and facial expressions. Posture and gesture are different as posture involves the whole body whereas gestures only involve arms and hands. An example of a posture is dog bowing, where the front of the body is arched downwardly, the rear is raised, and the tail is wagging, which indicates the desire to play. Gestures are much more present in animals with hands, such as primates. Chimpanzees for example have 66 unique gestures without idiosyncratic use, that is, they conserve the same function for all chimpanzees. In addition, some of these seem to be evolutionarily conserved, as other primates like orangutans and gorillas share 24 of these gestures with chimpanzees. Displays are present throughout the animal kingdom. The penguin mating display in Gebes involves the fanning of head feathers and the presentation of a piece of aquatic vegetation. Facial expressions have been well-studied in humans and it has been shown that there are 7 pan-culturally recognised facial expressions. These expressions are: anger, joy, fear, sadness, surprise, disgust, and contempt. Though, contempt is an exception in that it isn’t present in all cultures.
Recent comments