. >> reporter: scientists across the globe, including bill ziegler at brookfield have questioned the findings of the research. still, the potential backlash against these endangered animals is worrisome. >> my concern is if we don't word it right and people become afraid of pangolins, they may go out and if they find a pangolin in the wild in which case there is no real issue there, it's not a danger to you as far as transferring a disease, they would kill it anyway, because they're afraid of it. >> reporter: even though it's illegal worldwide, these odd-looking animals are heavily poached for their prized meat and their scales which are believed to have medicinal value, earning them a title as the most trafficked mammals on the planet, and causing some populations around the globe to drop to critical levels, something ziegler's team is trying to change. the brookfield zoo is one of seven groups in the u.s. working to breed pangolins, and they're one of the most successful, with nine births over the past four years. but here's what scientists are up against. it's estimated up to half