Animals, Science

Why Do Zebras Have Stripes?

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Image: André Karwath
Image: André Karwath

A new study answers a question people have long asked themselves about the animal kingdom: Why do zebras have stripes?

If you want to try guessing the answer, stop reading now.

Have you guessed? OK, start reading again.

According to a new study, a zebra’s stripes most likely help to keep annoying, biting flies off them.

Scientists have thought that might be the reason.

However, they also had other theories: that the stripes provide camouflage to help them hide from enemies; to confuse their enemies; to help them stay cool; or for a social reason such as to attract a mate.

About two years ago, scientists tested the “biting flies” theory using horse models covered in a sticky substance. Horseflies tended not to land on the fake horses that had stripes painted on them.

The researchers felt that the stripes confused the flies’ “navigational system”—the flies’ ability to steer and land.

In order to be more certain, and to answer the question of why all horse-type animals don’t have stripes, a team of researchers at the University of California looked at a lot of information (data) on zebras from many sources.

They also studied information about similar types of animals including horses, to see where the stripes were and what the stripes looked like. They mapped where zebras live.

Then they looked at information about where biting flies and zebra-enemies (like hyenas) live. They discovered that zebras tend to live in the same areas where biting flies are present, which supported their theory.

Now that the researchers are pretty certain the stripes help zebras discourage flies, they want to do more research with that theory in mind. They will observe how biting flies act around striped and non-striped animals.

The research will be published in the April edition of the journal Nature Communications.

CURRICULUM CONNECTIONS
By Jonathan Tilly

Writing/Discussion Prompt
Think of an animal that you think is interesting. Choose one feature about that animal and make a theory about why having that feature would be advantageous? Do some animals have features that are disadvantageous? Which ones?

Reading Prompt: Elements of Style
In today’s article, the author interuppted the story to give readers a chance to make a prediction before they read -on. What does this tell you about the readers style and the tone of the article? What other ways to writers communicate style and tone?

Primary
Identify some elements of style, includ- ing voice, word choice, and different types of sentences, and explain how they help readers understand texts (OME, Reading: 2.4).

Junior
Identify various elements of style – including word choice and the use of similes, personification, comparative adjectives, and sentences of different types, lengths, and structures – and explain how they help communicate meaning (OME, Reading: 2.4).

Intermediate
identify various elements of style – including foreshadowing, metaphor, and symbolism – and explain how they help communicate meaning and enhance the effectiveness of texts  (OME, Reading: 2.4).

Grammar Feature: Italics
The author of today’s story uses italics, which is a type of font that appears slanted, to step outside the story. When the author has finished making a side point, the font changes back to normal. Where else have you seen different styles used to communicate with the reader? Is using certain fonts, styles and sizes an effective way to communicate with your reader? Why do you think so?