Pray That Climate Change Doesn't Make Us Eat What It's Making Madagascar's Lemurs Eat

The greater bamboo lemur is a small, cat-size primate living on the island of Madagascar and is considered to be one of the most endangered primates on earth. Jukka Jernvall

Sensible primates eat a lot of fruit because fruit is good for you, but a study published today in the journal Scientific Reports explains how the diets of Madagascar's lemurs contain almost no fruit, and are instead disproportionately heavy in leaves. Leaves can be kind of nutritious if they're young and fresh, but another study published last week in Current Biology describes how climate change is making those more and more scarce, leaving the lemurs with only dry tree bark. It's potentially a bleak look at how our own diets and digestive tracts might have to evolve in response to climate change.

"If I was going to relate it to humans, I'd say, well, bamboo is a grass and rice is a grass and humans eat rice, so the climate changing is going to also impact humans because of the same issues [impacting lemurs]," primatologist Patricia Wright told Newsweek. "Humans just aren't critically endangered like they are."

The studies were conducted without relation to one another, but Wright happens to be a coauthor on both. It was Wright, back in the 1980s, who discovered that the greater bamboo lemur was not in fact extinct, as had been previously believed. Now, though, the lemurs are facing starvation.

The Scientific Reports study found that regions with unusually low levels of nitrogen in their soil bear fruit that's correspondingly low in protein—with the most nitrogen-poor soil studied anywhere in Africa, Asia, or the Americas, Madagascar's fruit is just too nutritionally pointless for the lemurs to bother with. In theory the bamboo they turn to instead should be able to sustain them, but climate change is drying the more edible bits and leaving the lemurs with only the portion of the plant known as culm. This is the driest part, and essentially combines all the taste of emergency rations with all the nutritional value of wood chips.

A greater bamboo lemur infant born in the beginning of the rainy season. Jukka Jernvall

Anyone who has ever actually watched a giant panda for more than a few seconds has realized why massive quantities of nutritionally pointless food followed by lots of hibernating is not an exciting way to live. Fortunately, for us anyway, a key difference remaining between the greater bamboo lemur and humans is flexibility in diet. Lemurs are specialists, which makes them more vulnerable to the effects of climate change than species like humans, which prefer to eat all kinds of things. The Current Biology researchers observed the lemurs for 18 months and found that they subsisted 95 percent of the time on the same single species of bamboo. But they're only meant to have to resort culm in the driest part of the season, from August to November.

"But each year the dry season gets longer by I think about a day," Wright said. "So by 2070 it's going to be like two months drier … that's definitely relevant to humans."

She and her Current Biology colleagues have plans to take what they've learned and build bamboo corridors this coming January, when it'll be wetter, in the hopes of reconnecting stranded lemur populations to more fertile habitats. Continuing to observe how the lemurs' physiology and behavior adapts in the face of climate change might provide insight we could apply to humans, especially those living in the hottest and driest parts of the world — if the lemurs don't go extinct first.