An elephant herd travels near Mount Kilimanjaro in Tanzania in Africa.

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The Elephant Detective

Samuel Wasser uses science to fight the illegal ivory trade

COURTESY OF UNIVERSITY OF WASHINGTON CENTER FOR CONSERVATION BIOLOGY

Tusks are extremely helpful when you’re an African elephant. You can use them to scrape tasty bark off trees or to dig for water underground. If a lion attacks your calf, you can use your tusks to fight it off.

Unfortunately, some people value tusks too. Every year, as many as 40,000 African elephants are poached, or hunted illegally, for their tusks. Poachers sell the tusks to be carved into jewelry and other objects.

Samuel Wasser has seen this problem firsthand. He’s a biologist at the University of Washington in Seattle. In the 1980s, he was studying monkeys in eastern Africa. He kept finding elephants that poachers had killed. “I realized I needed to shift what I do,” says Wasser.

Since then, Wasser has been studying African elephants. What he learns is helping authorities track down poachers.

African elephants need their tusks. They use them in many ways. They scrape bark off trees for food. They dig for water underground. If a lion attacks a calf, elephants fight back with their tusks.

Unfortunately, some people value tusks too. Every year, as many as 40,000 African elephants are poached. This means they are hunted illegally. Poachers sell the tusks. The tusks are carved into jewelry and other objects.

Samuel Wasser has seen this problem up close. He’s a biologist at the University of Washington. It’s located in Seattle. In the 1980s, he was studying monkeys in eastern Africa. He kept finding elephants killed by poachers. “I realized I needed to shift what I do,” says Wasser.

Since then, Wasser has been studying African elephants. He helps authorities track down poachers.

Hunted Down

Courtesy of University of Washington Center for Conservation Biology

Elephant tusks are made of a hard white material called ivory. Before plastic became popular in the 1940s, people used ivory to make everything from hairbrushes to piano keys. This devastated the African elephant population. In the early 1800s, about 26 million elephants lived on the continent. Now only about 400,000 are left.

In 1990, it became illegal to sell African elephant ivory. But  people do it anyway. Buyers pay thousands of dollars per tusk. Elephants roam huge areas, making it hard for rangers to protect them from poachers. In most cases the criminals aren’t caught.

Occasionally, inspectors at shipping ports spot illegal ivory. That’s what happened in May 2015, when police in Singapore found more than 1,000 African elephant tusks in a shipping container. But the officials didn’t know where the smuggled ivory came from. That’s where Wasser could help.

Elephant tusks are made of a hard white material. It’s called ivory. Before plastic became popular in the 1940s, people used ivory to make everything from hairbrushes to piano keys. This devastated the African elephant population. In the early 1800s, about 26 million elephants lived in Africa. Now only about 400,000 are left.

It became illegal to sell African elephant ivory in 1990. But people do it anyway. Buyers pay thousands of dollars per tusk. 

Elephants roam huge areas. It’s hard for rangers to protect them from poachers. In most cases the criminals aren’t caught.

Sometimes, inspectors at ports at spot illegal ivory. That happened in May 2015 in Singapore. Police found more than 1,000 African elephant tusks in a shipping container. But they didn’t know where the ivory came from. That’s where Wasser could help.

tobkatrina/Shutterstock.com

Only about 400,000 African elephants remain in the wild. Poaching has reduced their numbers.

On the Case

To investigate the ivory shipment, Wasser’s team sawed a sample the size of a jellybean off some of the tusks. They isolated each sample’s DNA—a material inside the cells of all living things. They compared the DNA from poached tusks to DNA collected from living elephants across Africa. This helped them determine where a poached elephant came from.

By the end of 2015, Wasser had enough data to identify two areas in central Africa where many elephants were being hunted. He shared what he learned with law enforcement officials.

To investigate the ivory shipment, Wasser’s team sawed a sample from the tusks. It was about the size of a jellybean. They took DNA from each tusk. This is the material inside the cells of all living things. They compared the DNA from poached tusks with DNA collected from living elephants across Africa.

This helped them find where a poached elephant came from. By the end of 2015, Wasser had a lot of data. He could identify two areas in central Africa where many elephants were being hunted. He shared what he learned with law enforcement officials.

Kate Brooks/Redux

Samuel Wasser can track where an elephant was poached using DNA, or genetic information, from its tusk.

Catching Criminals

Unfortunately, identifying the danger zones wasn’t enough to stop the poaching. Wasser has expanded his work. In 2017, his team realized that tusks from one elephant are often split into different shipments. By finding these pairs, Wasser can figure out which shipments were made by the same criminal groups. Authorities use this evidence to identify top poaching suspects.

Wasser hopes his efforts will help elephants. If poaching continues at this rate, the animals could die out. Even the loss of one elephant affects the whole herd, says Wasser. “Elephants are very smart,” he says. “They need each other. That’s why I do what I do.”

But this didn’t stop the poaching. So Wasser has expanded his work. In 2017, his team realized that tusks from one elephant are often split into different shipments. By finding these pairs, Wasser can figure out which shipments were made by the same criminal groups. Authorities use this evidence to identify top poaching suspects.

Wasser hopes his work will help elephants. If poaching like this continues, the animals could die out. Losing one elephant affects the whole herd, says Wasser. “Elephants are very smart,” he says. “They need each other. That’s why I do what I do.”

Scientists can use the distance around the base of a tusk, called its circumference, to tell how old an elephant was when it died. The line plot above shows this measurement for one group of tusks taken from poachers in 2013. Which circumference was the most frequent?

A. 3/5 foot

B. 4/5 foot

C. 1 foot

D. 1 1/5 feet

Scientists can use the distance around the base of a tusk, called its circumference, to tell how old an elephant was when it died. The line plot above shows this measurement for one group of tusks taken from poachers in 2013. Which circumference was the most frequent?

A. 3/5 foot

B. 4/5 foot

C. 1 foot

D. 1 1/5 feet

How many of the tusks were  foot long?

A. 0

B. 1

C. 2

D. 3

How many of the tusks were  foot long?

A. 0

B. 1

C. 2

D. 3

Tusks that are from the same elephant have the same circumference. So Wasser identifies pairs of tusks so that he only needs to test the DNA from one. Which tusks in Group A could NOT come from the same elephant as another tusk in the group? Explain how you know.

Tusks that are from the same elephant have the same circumference. So Wasser identifies pairs of tusks so that he only needs to test the DNA from one. Which tusks in Group A could NOT come from the same elephant as another tusk in the group? Explain how you know.

Scientists analyzed another set of tusks with the following circumferences: 1 foot, 3/5 foot, 4/5 foot, 1 1/5 feet, 4/5 foot, 1 foot, 1 1/5 feet, 1 2/5 feet. Create a line plot displaying these tusk circumferences for the elephants in Group B.

Scientists analyzed another set of tusks with the following circumferences: 1 foot, 3/5 foot, 4/5 foot, 1 1/5 feet, 4/5 foot, 1 foot, 1 1/5 feet, 1 2/5 feet. Create a line plot displaying these tusk circumferences for the elephants in Group B.

The older an elephant is when it dies, the greater the circumference of its tusks. Which group of tusks came from older elephants: Group A or Group B? Explain your reasoning.

The older an elephant is when it dies, the greater the circumference of its tusks. Which group of tusks came from older elephants: Group A or Group B? Explain your reasoning.

Bonus Article

Continue your lesson with an earth science connection!

 

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