Animals show off because they want to attract a mate. As an example peacocks have a large plumage of feathers and when near a female ( called a peahen) they show off their feathers by fanning them out. The female sees the colors on the peacock and if the colors are bright and vivid than she will chose him. The peahen will chose the male with the brightest colors because if they have bright colors than that means that they are happy and healthy and the peahen wants only the best for her offspring.
