Jonathan Lambert

Chinmay and his colleagues published a big analysis of all this work in the journal PNAS in June, looking for broader patterns on how scavenging species influence health, and also how those scavenging species are doing.

They looked at over 1,300 species and found that up to 36% are declining or threatened with extinction.

Yeah, it's a combination of habitat loss, hunting, and the wildlife trade.

But they found that not all scavengers were equally at risk.

The biggest, most specialized scavengers, things like vultures or hyenas, were more likely to be threatened.

Smaller or less specialized scavengers who sometimes eat carrion but can eat other things, too.

Think things like rats or mice or in India, feral dogs.

Chinmay actually thought that going into his study, but he and his colleagues ended up finding that these smaller scavengers just aren't as good at scavenging as what they call apex scavengers.

Yeah.

And smaller scavengers like rats or dogs are more likely to carry pathogens themselves.

Plus, humans are a lot more likely to come into close contact with those than, say, a vulture.

Chinmay says basically that a world with fewer apex scavengers is one that could make humans sicker.

Other researchers I spoke to agreed.

Here's Christopher O'Brien, a biologist at Maastricht University.

Conservation, basically.

Chinmay and his colleagues argue that taking steps to conserve top scavengers by protecting their habitat or restricting their hunting could help preserve some of the benefits they provide.

But what happened to India's vultures offers a cautionary tale of sorts.

Yeah, so the Indian government banned the use of that toxic painkiller by veterinarians in 2006.

But the vultures are still struggling to get back to anything close to their old numbers.

Yeah, and this all just shows how dependent our collective health is on the natural world, and parts of it that we often ignore.