Analyzing the DNA of more than 4,000 elephant tusks from 49 seizures of illegally traded ivory dating back to 2002 suggests that just a few criminal networks control ivory trafficking out of Africa. Poachers repeatedly target the same elephant populations, according to research led by University of Washington conservation biologist Samuel Wasser and published Monday in the journal Nature Human Behavior. Law enforcement officials say identifying these tightly woven networks helps them build criminal cases against traffickers. The World's environment correspondent Carolyn Beeler reports.
Sign up for The Top of the World, delivered to your inbox every weekday morning.