Why Do Animal Eyes Glow? Search for the Answer – Play online

Read the sources

One night, Sofia shined a flashlight under her porch and saw two glowing eyes. They belonged to a raccoon, which quickly waddled away. The next day, Sofia posted two questions on her class Wonder Wall: "Why do some animals' eyes glow in the dark?" and "Why do people's eyes look red in some flash photos?" Her teacher's rule is to answer with a source written by experts. Read the three sources Sofia found online.

Source 1: Search Results

Search: why do animal eyes glow at night

Result 1: Night Light Outlet (Ad)
Big sale this week! Shop bright flashlights for camping, hiking, and more.

Result 2: Eyeshine: Why Some Animals' Eyes Glow
Riverside Nature Center. Learn how a special layer at the back of the eye helps many animals see at night.

Result 3: Ten Fun Facts About House Cats
Pet Corner Blog. Cats love boxes, chase string, and nap in sunny spots.

Result 4: Glow-in-the-Dark Animal Masks
Craft Time. Make animal masks with paint that shines after dark.

Source 2: Article "Eyeshine" from the Riverside Nature Center Website

1What Is Eyeshine?
Eyeshine is the glow you see when a light shines on the eyes of certain animals in the dark. It happens because many animals have a special layer of tissue at the back of each eye. This layer works like a mirror. Its name is the tapetum lucidum (tuh-PEE-tum LOO-sih-dum).

2How the Layer Helps
Light enters the eye and passes through the retina, the part of the eye that senses light. In an eye with the mirror-like layer, light that passes through the retina bounces back and passes through it a second time. This second chance helps the animal see better in dim light. The layer does not let an animal see in total darkness, though. Every eye needs at least a little light to see.

3Which Animals Have It?
Many animals have eyeshine, including cats, dogs, raccoons, and deer. A lot of these animals are active at night or in the dim light of dawn and dusk. Humans do not have the mirror-like layer, and neither do many animals that are active mainly during the day.

4Colors of Eyeshine
Eyeshine can look green, yellow, blue, white, or even red, depending on the kind of animal.

Source 3: Video Page "Night Eyes Explained" from the Riverside Nature Center

Video length: 7 minutes, 45 seconds
Chapters:
0:00 Welcome
0:40 Spotting eyeshine on a night walk
2:10 Inside the eye: the mirror layer
3:55 Why eyeshine comes in different colors
5:05 Why people get red eye in photos
6:30 How to look for eyeshine safely

Part of the transcript, starting at 5:05
People do not have the mirror layer, so why do our eyes sometimes look red in flash photos? In a dark room, the pupils of your eyes open wide to let in more light. When the camera flash goes off, its light shines through the open pupils and reflects off the back of the eye, which has many tiny blood vessels. The blood vessels make the reflected light look red.

Part of the transcript, starting at 6:30
To spot eyeshine, hold your flashlight close to your eyes and shine it toward bushes or tall grass. The light bounces back toward where it came from, so you see the glow best when the light is near your own eyes. Always stay a safe distance away, and never try to touch or follow a wild animal.

Search smart

Decide where Sofia should look before she reads closely.

Which search result should Sofia open first to answer her question about glowing eyes?

A. Result 1: Night Light OutletB. Result 2: Riverside Nature CenterC. Result 3: Pet Corner BlogD. Result 4: Craft Time

Why is Result 1 a poor choice for Sofia's question?

A. It explains eyeshine, but only for animals that live in the ocean.B. It was written by experts who study raccoons and other wildlife.C. It is an ad that is trying to sell flashlights, not explain eyes.D. It is about cats, so it cannot tell her anything about raccoons.

Sofia has more questions. Match each question to the part of a source that answers it fastest.

Sofia wants to skip to the part of the video about why eyeshine comes in different colors. Write the time where that chapter starts.

The chapter starts at .

Find the answers

Go back to the sources to locate each answer.

Read paragraph 2 of Source 2, "How the Layer Helps." Underline the sentence that tells what happens to light that reaches the mirror-like layer.

Sofia's dog's eyes glow in her flashlight beam, but her brother's eyes do not. Which detail from the sources explains why?

A. Eyeshine can look green, yellow, blue, white, or red.B. Every eye needs at least a little light to see.C. The glow is easiest to see with a light near your eyes.D. Dogs have the mirror-like layer, but humans do not.

Which TWO details from the video explain why people's eyes can look red in flash photos? Choose two.

A. The pupils open wide in a dark room.B. People have a mirror-like layer in each eye.C. Flash light reflects off tiny blood vessels.D. The glow is brightest when a light is near you.

Each fact below is stated in only one of these two sources. Sort the facts by the source that states them.

Before class, Sofia has two minutes to check one more fact: Can a raccoon see when there is no light at all? What is the fastest way to find out?

A. Watch the whole video from the very beginning.B. Open each search result one at a time.C. Read the article section "How the Layer Helps."D. Read the article section "Colors of Eyeshine."

10.

Sofia writes her answer for the Wonder Wall. Complete it with words from the word bank.

Many animals have a layer at the back of the eye that works like a . Light passes through the a second time, so the animal can see better in dim light.

11.

Explain which source answered each of Sofia's two Wonder Wall questions, and why the search results alone were not enough. Use details from the sources.