Why Are Lemurs So Weird? Maybe Because They Don't Eat Enough Fruit

Luca Santini
Luca Santini

Lemurs are weird animals. Found only in Madagascar, they're primates (like apes, gorillas, and us), but unlike all other primates, they do things like hibernate and sleep in caves—that is, when they sleep, because they don't follow the normal nocturnal/diurnal pattern. Oh, and unlike many primates, most of them aren't frugivores. Meaning, they don't eat fruit. Their diet is much heavier on leaves than other primates.

A new study in the journal Scientific Reports suggests a reason why: The fruit available on the island doesn't have enough protein in it to meet their dietary needs, so they evolved a diet that didn't include it. The researchers, an international team led by Giuseppe Donati of Oxford Brookes University, combed through 79 different studies to analyze the nitrogen content (a necessary component of protein) of fruits cross the world and compare the rates of primate communities who eat fruit in different regions.

The higher the protein content of the fruits found in an area, they discovered, the more the animals relied on them as a food source. The fruits of Madagascar are also lower in nitrogen than fruits elsewhere, and in turn, the number of lemur communities in Madagascar that eat fruit is significantly lower than the number of primates in the Western Hemisphere, Asia, or elsewhere in Africa that eat fruit. (Only two genera of lemur subsist mainly on fruit, while elsewhere in the world, even primates that eat leaves still enjoy a good fruit salad now and then.)

"Lemurs are equal parts ridiculously cool and totally bizarre in that they represent the extremes and the extremely strange in the primate world," the Field Museum's Abigail Derby Lewis, a senior conservation ecologist, said in a press release. And studying their dietary patterns suggests why they've evolved to be so strange in comparison to their other primate relatives. Unable to get protein from fruit, they had to eat more leaves. To eat more leaves, their sleep schedules had to accommodate round-the-clock eating, which would explain their odd sleep patterns. And to conserve energy, they go into hibernation.

Lemurs aren't the only primates that go for leaves over fruit. So do howler monkeys. A March 2017 study found that primates that do eat fruit tend to have bigger brains. Nutritious fruit might not be the sole factor determining how primate species evolve, but it's clear that having access to it matters significantly. 

Friday’s Best Amazon Deals Include Digital Projectors, Ugly Christmas Sweaters, and Speakers

As a recurring feature, our team combs the web and shares some amazing Amazon deals we’ve turned up. Here’s what caught our eye today, December 4. Mental Floss has affiliate relationships with certain retailers, including Amazon, and may receive a small percentage of any sale. But we only get commission on items you buy and don’t return, so we’re only happy if you’re happy. Good luck deal hunting!

3D Map Shows the Milky Way Galaxy in Unprecedented Detail


It's our galactic home, but the Milky Way contains many mysteries scientists are working to unravel. Now, as The Guardian reports, astronomers at the European Space Agency have built a 3D map that provides the most detailed look at our galaxy yet.

The data displayed in the graphic below has been seven years in the making. In 2013, the ESA launched its Gaia observatory from Kourou in French Guiana. Since then, two high-powered telescopes aboard the spacecraft have been sweeping the skies, recording the locations, movements, and changes in brightness of more than a billion stars in the Milky Way and beyond.

Using Gaia's findings, astronomers put together a 3D map that allows scientists to study the galaxy in greater depth than ever before. The data has made it possible to measure the acceleration of the solar system. By comparing the solar system's movement to that of more remote celestial objects, researchers have determined that the solar system is slowly falling toward the center of the galaxy at an acceleration of 7 millimeters per second per year, The Guardian reports. Additionally, the map reveals how matter is distributed throughout the Milky Way. With this information, scientists should be able to get an estimate of the galaxy's mass.

Gaia's observations may also hold clues to the Milky Way's past and future. The data holds remnants of the 10-billion-year-old disc that made up the edge of the star system. By comparing it to the shape of the Milky Way today, astronomers have determined that the disc will continue to expand as new stars are created.

The Gaia observatory was launched with the mission of gathering an updated star census. The previous census was conducted in 1957, and Gaia's new data reaches four times farther and accounts for 100 times more stars.

[h/t The Guardian]