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However, if birds have the same eye size but different body masses, the larger species sings later than the smaller. This may be because the smaller bird has to start the day earlier because of weight loss overnight. [16] Overnight weight loss for small birds is typically 5-10% and may be over 15% on cold winter nights. [16]
Blindness in animals. Visual perception in animals plays an important role in the animal kingdom, most importantly for the identification of food sources and avoidance of predators. For this reason, blindness in animals is a unique topic of study. In general, nocturnal or subterranean animals have less interest in the visual world, and depend ...
Optic neuropathy is damage to the optic nerve from any cause. The optic nerve is a bundle of millions of fibers in the retina that sends visual signals to the brain. Damage and death of these nerve cells, or neurons, leads to characteristic features of optic neuropathy. The main symptom is loss of vision, with colors appearing subtly washed out ...
Tetrachromacy. The four pigments in a bird's cone cells (in this example, estrildid finches) extend the range of color vision into the ultraviolet. [ 1] Tetrachromacy (from Greek tetra, meaning "four" and chroma, meaning "color") is the condition of possessing four independent channels for conveying color information, or possessing four types ...
Bird, reptilian, and monotreme cone cells. The difference in the signals received from the three cone types allows the brain to perceive a continuous range of colors, through the opponent process of color vision. (Rod cells have a peak sensitivity at 498 nm, roughly halfway between the peak sensitivities of the S and M cones.)
List of birds. Penguins. Ostriches. This article lists living orders and families of birds. The links below should then lead to family accounts and hence to individual species. The passerines (perching birds) alone account for well over 5,000 species. In total there are about 10,000 species of birds described worldwide, though one estimate of ...
Monocular vision vision is known as seeing and using only one eye in the human species. Depth perception in monocular vision is reduced compared to binocular vision, but still is active primarily due to accommodation of the eye and motion parallax. The word monocular comes from the Greek root, mono for single, and the Latin root, oculus for eye.
Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and reddish pink or blue eyes. [ 1][ 2] Individuals with the condition are referred to as albinos . Varied use and interpretation of the terms mean that written reports of albinistic animals can be difficult to verify.