In 1983, biologist Sam Wasser and a small team were conducting field research near the Selous Game Reserve in southeast Tanzania when they came upon a grisly scene: a "kill site." The forest floor was covered in dried blood. In the carnage, Wasser noticed two elephant teeth: one a large tooth from an adult elephant, the other, a small tooth from a baby elephant. This puzzled him. Collectors have longed prized adult elephants' ivory tusks. But why the baby, whose meager ivory certainly wasn't worth the poachers' time? Then it hit him.
"What we realized is the poachers had killed the baby so the mother would come back to protect it. Then they shot her," says the 62-year-old Wasser, reflecting on the event.
This experience set the AAAS member on a path that would define much of his career and has taken Wasser from fighting poaching in the forests and savannahs of Africa to examining the ecological effects of oil extraction in the Canadian tar sands. Wasser now heads the Center for Conservation Biology at the University of Washington. Among his lab's many conservation efforts is a mission to save Africa's remaining elephants. At the heart of his research is a series of noninvasive methods Wasser developed for studying animals in the wild. The key to his research is found in scat.
While scat, or feces, is viewed with revulsion by most, for Wasser it's a treasure trove of biological and ecological information. From scat collected in the wild, Wasser has extracted DNA. Not only from the scat maker, but also from what the animal ate. He's searched for the presence of toxins such as DDT and PCBs. He's studied the level of stress hormones in caribou and baboons, to name a few. And, using new, next gen sequencing, he's even tracking the health of animals' microbiomes, the ecosystems of microbes the animals host. What results is a tapestry of data that Wasser weaves together to get a multifaceted ecological picture of what's happening in an environment.
"You can see how putting all of these things together can give you a phenomenal tool for studying community ecology on all kinds of levels," says Wasser.
To date, Wasser has used scat to do everything from studying killer whale health (whale scat floats for about 30 minutes) to monitoring northern spotted owl populations. Frequently this is done with the aid of dogs, often rescued dogs, that are trained to sniff out scat in the wild using methods similar to those employed by law enforcement-trained, drug-sniffing dogs. Law enforcement techniques have also inspired Wasser's current work tracking elephant poachers.
Employing forensic techniques similar to those used to catch murderers as well as to identify the remains of individuals from their teeth, Wasser and colleagues have teamed up with investigators at INTERPOL among others to track illegal ivory shipments back to their source in Africa. There is real urgency in this work. Researchers estimate Africa only has roughly 400,000 elephants left, and they're being killed at the phenomenal rate of about 50,000 a year, a speed not seen since the poaching sprees of the 1980s that killed roughly 700,000 elephants, raising for the first time the specter of extinction.
"We are running out of time," says Wasser.
The forensics Wasser employs exploit idiosyncrasies in the genome called microsatellites, repeating noncoding nucleotide sequences. They're not genes, as such, but "junk" DNA. But, as the saying goes, one person's trash is another's treasure. For scientists like Wasser, microsatellites are a boon. Because they accumulate mutations quickly, researchers can use microsatellites to genetically "fingerprint" individuals and even whole communities.
Comparing microsatellite data found in confiscated ivory to microsatellite data found in elephant scat found in the wild and used to make a comprehensive distribution map of Arica's elephant populations, Wasser and his team have been able to trace poached ivory back to the specific country and, in some cases, even the valley where the elephants were slaughtered. The project's latest findings were published this summer in Science. What Wasser and colleagues found surprised both law enforcement and the scientific community.
Of the 28 shipments his team was able to get its hands on, all but one were concentrated in just four areas in Africa. What's more, seizures since 2006 were largely concentrated in just two areas: Tanzania and neighboring northern Mozambique for savannah elephants and northeastern Gabon and neighboring northwestern Republic of Congo, southeastern Cameroon, and southwestern Central African Republic for forest elephants.
"Everyone thought these huge seizures were from poaching from all over Africa," explains Wasser. "What we showed is these poachers keep hitting the same areas over and over."
Now that there are definitive findings showing exactly where elephants are being hit the hardest, Wasser says his hope is law enforcement will be able to use this research to focus their efforts and stop the killing of Africa's elephants before it's too late.
"These poachers have been getting away with murder for a long time," says Wasser. "We need to stop the killing now."