Eyeshine

Eyeshine or tapetum lucidum is when an animal's eyes glow in the dark.

When light goes into the animal's eye, it hits a web of cells called the tapetum behind the light collector. These cells reflect the light like a mirror. The light goes through the animal's light collector twice, once on the way in and once on the way out. This helps the animal see in the dark.^[1]

Most animals with eyeshine are animals with fur, but bullfrogs and some spiders have eyeshine too.

Different animals' eyes glow different colors:

• Alligator - red-orange
• Deer - green
• Cat - gold or green
• Barred owl - bright red^[2]

1. ↑ Ilo Hiller (1983) "Eyeshine." Young Naturalist. The Louise Lindsey Merrick Texas Environment Series, No. 6, pp. 40-42. Texas A&M University Press, College Station. cited in Texas Department of Parks and Wildlife Young Naturalist webpage
2. ↑ Asher Elbein (October 26, 2018). "Is the Mothman of West Virginia an Owl?". Audubon Society. Retrieved August 8, 2021.