You’ve heard about the canary in the coal mine. And frogs as signals of environmental degradation. The latest animal to serve as a harbinger of toxic exposures to humans may be: monkeys. That’s according to research in the American Journal of Physical Anthropology.

Macaques live in close quarters with people in parts of Nepal. So scientists thought that the monkeys might be “sentinels” for human lead exposure. Lead can have multiple deleterious health effects, from impairing neurological development to kidney, liver, and circulatory and respiratory problems.

The research team wanted to avoid stressing the animals, so they took a few strands of hair from individuals living around a temple in Katmandu. It’s in a densely populated area that contains old lead batteries, flaking lead-based paint, and lead-contaminated soil, a by-product of leaded gas. Lead levels varied in the macaques, but the highest concentrations were in the young—like human children, young macaques tend to pick up objects and stick them in their mouths.

Scientists say they’ll next try to nail down whether macaque lead levels are indeed predictive of lead poisoning in humans. The hope is that monitoring macaque lead can improve conditions for humans and monkeys alike.

—Cynthia Graber

[The above text is an exact transcript of this podcast.]