It isn't only elephants that are suffering from humans' insatiable thirst for ivory. A new study notes hippopotamuses, already predicted by some to disappear within 100 years, may be dying at unexpected rates to fuel the trade of ivory ornaments made from hippo teeth.

Since 1975, 1.7 million pounds of hippo teeth have been traded around the world, with 90% of that trade passing through Hong Kong, according to researchers at the University of Hong Kong.

Of that 90%, 75% has come from Uganda and Tanzania. Like Hong Kong, both African countries report their legal trade volumes to CITES, an organization that monitors trade in threatened species.

What irks researchers, however, is that the reported volumes don't add up. CITES data shows Hong Kong has actually received more hippo teeth from Tanzania since 1980 than Tanzania claims it exported, and less hippo teeth from Uganda since 1991 than Uganda claims it sent, notes the study in the African Journal of Ecology.

The result is 30,860 pounds of hippo teeth—the equivalent from 2,700 hippos, or 2% of the animal's global population—overlooked, reports Quartz. "If authorities do not more diligently monitor the international trade in threatened species, those species could be exposed to unmanageable exploitation levels, which could lead to extinction," says study author Alexandra Andersson in a release.

"The fate of hippos—and a plethora of other species—could depend on it." (People are also getting ivory from … woolly mammoths.)

This article originally appeared on Newser: Hippos in Danger Because of Desire for Their Teeth