Tanzania

Counting ZZZZebras

by Charlotte McGlone

Chapel Hill, NC, United States

The Serengeti National Park encompasses 5,700 miles of savannah in Tanzania. It is home to hundreds of species of African wildlife, most abundantly, zebras, gazelles, and wildebeest, as well as their ferocious predators: lions, leopards and cheetahs. Scientists and adventurers come from all corners of the globe to experience this untouched slice of the wild.

Maasai Inhabitants

Before the land was designated as a national park, it was home to the nomadic Maasai people. Since the 17th century, the Maasai have inhabited this area of Tanzania and also its next-door neighbor, Kenya. Although the British government forced them off the Serengeti in the 1920s, the Maasai still live on the surrounding land. Their livelihood is based on cattle, and each tribe moves around constantly to find new grazing fields for its herds of livestock. They also have a rich musical culture, and often engage in call-and-response style singing, which they accompany with exciting dance moves!

19th Century Exploration

In 1892, a German explorer named Oscar Baumann made his way through the exotic Tanzanian ecosystem. During his journey, Baumann took many notes on the beautiful wildlife he saw around him, as well as on the interesting culture of the Maasai. His legacy of observation and discovery has been continued with the creation of the Serengeti Research Institute, established in 1962. In fact, the word Serengeti means an “extended plain” in the Maasai language.

Counting Heads in the Herds

One of the most important jobs of this foundation is to monitor the yearly migration of around 1.5 million wildebeest, 250,000 gazelles, and 250,000 zebras. We know these numbers because scientists count them. Well, they don’t count all of them; actually, they estimate the totals. One way they estimate is through the capture/recapture technique.

Have you ever seen a scientist tag an animal? She captures an animal from the population she wants to keep track of and then attaches some sort of marker or tracking device to a part of its body. She then releases it to wander back to its family. She repeats this technique several times. Later, to estimate the individuals in an area, the scientist will isolate a few and check to see how many carry tags. This research method yields an estimate of the total number present in an area.

Migration Time

Now, back to the Serengeti. This vast herd of herbivores makes its way across the Serengeti in search of water every June when the dry season begins. These migrations can cover up to 700 miles. Along the way, the animals face numerous predators and natural threats. They are constantly trailed by hungry prides of lions, lurking crocodiles, and lighting-fast cheetahs. This trek is most dangerous for the young foals and calves in the herd. Although baby zebras are able to walk within 10 minutes of being born, and can reach the 35 miles per hour speeds of their parents at just a few days old, they are still the prime targets of the many predators stalking them.

Miraculously, the herd makes its way to new grazing fields, and they enjoy relative safety there for a few months before returning back in the direction they came. Throughout this journey, scientists are tracking their every step, and constantly making new discoveries about the amazing Serengeti and the creatures that live there.

So, the next time you are having trouble sleeping, think like a scientist on the Serengeti and count zzzzzebras.

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Math Questions

  1. A researcher wants to estimate the number of zebras in the park by using the capture/recapture technique. In March, her team captures, tags, and releases 75 zebras. The following March, her team returns and captures 130 zebras. Of those 130 zebras, 21 had a tag from the previous March. Use this information to estimate the total number of zebras in the park.
  2. Now make up your own numbers for this question and ask others in your group if they get the same result as you do!

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Extension Questions

  1. Do some research about how well protected or not the animals in the Serengeti are. Do you believe that enough is being done to preserve this unique ecosystem?

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Resources

  1. UNESCO page on the Serengeti as a World Heritage Site
  2. World Wildlife Fund page on the Serengeti
  3. Detailed migration map

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