News / Africa

Satellites Help Explain Zebra Migration

Multimedia

Audio
Joe DeCapua
Every year, zebras in Botswana begin a 580-kilometer migration looking for food. Even though it’s an annual event, researchers only had a general idea when it would start and they didn’t know which route the animals would take or why. That is, until now.


Sometime in September, zebras begin their trek from Botswana’s Okavango Delta to the Makgadikgadi Salt Pans. Pieter Beck, a research associate at the Woods Hole Research Center, was among those studying the migration.

“Like most large herbivores that naturally migrate, zebra migrations have been under threat. Across the globe, most of the big migrations already are under threat. So, conserving the ones that exist is of course important; and finding ways where people and wildlife can live together is critical if you want to achieve that,” he said.

One big mystery was how do zebras choose the route to the salt pans? It was not because the knowledge had been passed down from one generation to the next. Researchers knew that between 1968 and 2004 veterinary fences were built across potential migration routes. The fences were put up to help prevent wild buffalo from transmitting disease to cattle.

Within three years of the fences being taken down, the zebras began to migrate. Now, keep in mind that the fences were up for 36 years and that zebras usually live no more than 12 years in the wild.

“The fences were up longer than the lifespan of the zebra. So the zebra that we tracked making this hundreds of miles of migration – they couldn’t have learned it from their parents. So they actually rediscovered it using probably exploratory walks. It’s a very fascinating story in that sense and sort of a good news story in conservation. And these are unfortunately rare these days,” said Beck.

So, researchers turned to the U.S. space agency NASA and took a close look at some of its satellite images and data.

“The NASA instruments that we worked with orbit the Earth and they give us a global picture of rainfall and of vegetation productivity. So those are the two metrics we extracted. The rainfall data you can get for the tropics in particular. And we can see every six hours from satellites an estimate of how much it rained. For the vegetation data we can see globally every day, if there are no clouds, how productive the vegetation is. Is it green or is it wilted or is it dry?”

What Beck and his colleagues found was that when enough rain has fallen there’s a “surge in the greening of grasses.”

Beck said, “We do see that rainfall is what gets them going. That was very clear. But then, once they’re on the move, they appear to rely both on rainfall and the productivity of vegetation because the leg of migration we looked at is at the end of the dry season. So when we look at the vegetation that’s surrounding them and how green it is, really, we can tease out how fast the animals will migrate.”

And they’ll follow the greening vegetation. But Beck said the zebras are in tune with the environment and don’t simply move blindly in one direction.

“If the rains then abate or you get an interruption, then they’ll actually reverse their migration, which is something that had only very rarely been documented. They’ll reverse their migration and wait for the next spell of rains. Same thing when they return from the very productive grasslands where they are in the wet season. If you get a very late rain spell, they’ll actually reverse again and extend the period that they can graze in the grasslands,” he said.

So researchers wanted to know whether being in tune with their environment would help the zebras – and possibly other migrating animals -- adapt to climate change.

Beck said, “In our research we assessed the chance of those weather systems becoming decoupled and really the cues that animals rely on now not becoming reliable anymore in the future – and whether the animals’ behavior is adaptable enough to cope with that.”

That kind of knowledge could help in the conservation of wild animals. He also says knowing which migration routes animals will take may help game park rangers and others better protect them from poachers. Beck and his colleagues presented their findings in the Journal of Geophysical Research – Biogeosciences.

You May Like

India PM Modi's Party Distances Itself From Religious Conversions

BJP under fire for being slow to rein in hardline affiliate groups allegedly trying to promote Hindu-dominant agenda by luring Muslims and Christians to convert More

Anti-Whaling Group Found in Contempt of Court

Radical environmentalists who threw acid and smoke bombs at Japanese whalers in the waters off Antarctica continue their campaign to disrupt Japan's annual whale hunt More

UN's Ban Urges End to Discrimination Against Ebola Workers

Ban was speaking in Guinea on the second day of a whistle-stop tour aimed at thanking healthcare workers of the countries at the heart of the epidemic More

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
US Decision on Cuba Underscores Divisions Among Miami Cubansi
X
Sharon Behn
December 19, 2014 9:34 PM
For decades, older, more conservative Cubans have been gathering at Café Versailles on the corner of Calle Ocho to eat Cuban food and talk politics. After hearing of President Barack Obama’s decision, a number of them gathered in front of the café with posters to protest. VOA's Sharon Behn reports on the situation.
Video

Video US Decision on Cuba Underscores Divisions Among Miami Cubans

For decades, older, more conservative Cubans have been gathering at Café Versailles on the corner of Calle Ocho to eat Cuban food and talk politics. After hearing of President Barack Obama’s decision, a number of them gathered in front of the café with posters to protest. VOA's Sharon Behn reports on the situation.
Video

Video Three Cities Bid for Future Obama Presidential Library

President Barack Obama still has two years left in his term in office, but the effort to establish his post-presidential library is already underway. The bid for the Obama Presidential Library is down to four locations in three states -- New York, Hawaii, and Illinois. As VOA’s Kane Farabaugh reports, each of them played an important part in the president’s life before he reached the White House.
Video

Video Cuba Deal is Major Victory for Pope’s Diplomatic Initiatives

Pope Francis played a key role in brokering the US-Cuba deal that was made public earlier this week. It is the most stunning success so far in a series of peacemaking efforts by the pontiff. VOA religion reporter Jerome Socolovsky has more.
Video

Video Fears of More Political Gridlock in 2015

2014 proved to be a difficult year politically for President Barack Obama and a very good year for the U.S. Republican Party. Republican gains in the November midterm elections gave them control of the Senate and House of Representatives for the next two years -- setting the stage for more confrontation and gridlock in the final two years of the Obama presidency. VOA National Correspondent Jim Malone has a preview from Washington.
Video

Video Sudan School Becomes Target of Aerial Attacks

The school dropout rate is at an all-time high in Sudan's South Kordofan state because many schools have been destroyed during the three-year civil war between the government and SPLA-N rebel forces. Adam Bailes visited Sudan's Nuba Mountains' region and reports many children are simply too scared to go to school
Video

Video VOA Reporter Tours Devastated Peshawar School

Islamist militants wearing military uniforms and strapped with explosives attacked a military run school Tuesday in the northwestern Pakistani city of Peshawar. At least 141 people were killed in the horrific attack, most of them young students. VOA reporter Ayaz Gul visited the devastated school and attended the funeral of the principal who courageously tried to save her students from the deadly attack.
Video

Video Nigerians Fleeing Boko Haram Languish in Camp Near Capital

In its five-year effort to impose Islamic law in northeastern Nigeria, the Boko Haram extremist group has killed thousands of people and forced hundreds of thousands to flee. Some of those who ran for their lives now live in squalor on the edges of the capital, Abuja. Chris Stein reports for VOA.
Video

Video Aceh Rebuilt Decade After Tsunami, But Scars Remain

On December 26, 2004 there was an earthquake in the Indian Ocean so powerful it caused the Earth’s axis to wobble a few centimeters. Onshore on the island of Sumatra, the resulting tsunami was devastating. A decade later, VOA Correspondent Steve Herman reports from Banda Aceh, Indonesia, where although there is little remaining evidence of the physical devastation, the psychological scars among survivors remain.

All About America

AppleAndroid