Scientists observing chimpanzees applying insects to the wounds of their fellow apes have concluded that this previously undocumented behavior is proof that apes show empathy in the same way that humans do.

Researchers have been studying a specific group of chimpanzees, which share 99 percent of their DNA with humans, in the Loango National Park in Gabon for seven years.

In November 2019, Alessandra Mascaro and Lara Southern observed chimpanzees grabbing insects from the air and applying them to each other’s wounds. Mascaro captured the behavior on camera.

A year later, as the research team continued to monitor the chimpanzees, Southern observed a similar wound-tending event. She saw an adult female seize an insect and hand it to an adult male, dubbed Littlegrey, who had a deep open wound on his leg. After Littlegrey applied it to his injury, the female chimp was joined by two other chimps in touching the wound and rubbing the insect on it.

“The three unrelated chimpanzees seemed to perform these behaviors solely for the benefit of their group member,” said Southern.

The research team from Osnabrück University in Germany and the Ozouga Chimpanzee Project published their study in the journal Current Biology.

The team has focused for years on a band of about 45 chimpanzees at Loanga, examining their relationships, interactions and disputes with other groups, as well as their cognitive and communicative skills, hunting and tool use.

Study co-author Simone Pika of Osnabrück University called the wound-tending behavior clear evidence of prosocial behavior, or behavior invested in the interests of others, rather than just oneself.

“This is, for me, especially breathtaking because so many people doubt prosocial abilities in other animals,” she said. “Suddenly we have a species where we really see individuals caring for others.”

Wound-tending behavior was observed among chimps in the past but was limited in scope. “Self-medication — where individuals use plant parts or non-nutritional substances to combat pathogens or parasites — has been observed across multiple animal species including insects, reptiles, birds and mammals,” said Pika. Bees, bears and elephants are known to do it, too.

“Our two closest living relatives, chimpanzees and bonobos, for instance, swallow [the] leaves of plants with anthelmintic properties and chew bitter leaves that have chemical properties to kill intestinal parasites,” said Pika. In the past, chimps have been observed using twigs, for example, to extract tasty termites from rock-solid termite mounds. However, no one had observed chimps treating not only themselves but also others.

Humans are known to use several insect species to stave off sickness, Pika said, citing evidence dating back to 1400 B.C. She noted that insects can have antibiotic, antiviral and antiparasitic effects. The team theorized that applying insects to wounds may have an anti-inflammatory, antiseptic, analgesic or pain-relieving effect in the chimps.

An alternative explanation for the behavior is that if it has no beneficial effect, it may reflect the local chimpanzee culture in much the same way that human cultures do.

Going forward, the researchers want to identify the insects the chimps are using and observe which of them are applying the insects to others. “Studying great apes in their natural environments is crucial to shed light on our own cognitive evolution,” said study co-author and primatologist Tobias Deschner. Given apes’ importance to humanity, Deschner pleaded for their protection and the preservation of their habitats.

“We now aim to investigate the potential beneficial consequences of [their] surprising behavior,” he said.

“For me,” Pika said, “being interested in the cognitive skills of chimpanzees, it was particularly striking to witness that individuals not only treat their own but also the wounds of other nonrelated individuals. Such examples of clear prosocial behaviors are rarely observed in nonhuman species, but these observations may now also convince the skeptics.”

Edited by Siân Speakman and Kristen Butler

While megalodon sharks were indeed prehistoric giants, their shape may have differed from modern sharks, according to a new study.

Otodus megaladon hunted in the world’s oceans 15 to 3.6 million years ago. So far, they are known only by some vertebrae and enormous teeth, which resemble the smaller teeth found in modern great white sharks. Scientists have conjectured that the megalodon was 65 feet long, even though no complete skeleton has ever been found.

“The cartilage in shark bodies doesn’t preserve well, so there are currently no scientific means to support or refute previous studies on O. megalodon body forms,” said Phillip Sternes of University of California-Riverside. Sternes is the lead author of a study on the subject published in the journal Historical Biology. So far, paleontologists have inferred the body shape of megalodon from what they know about modern sharks.

Great white sharks (Carcharodon carcharias) are unlike other fish because they are partially warm-blooded. “Great whites are among the fastest swimming sharks, so Megalodons were likely also big, fast sharks you would not want to run into in the open ocean,” said Sternes. The megalodon, he believes, may have been similarly warm-blooded.

There are 17 species of sharks within the seven shark families of the Lamniformes order. By averaging the fin and body shapes of five species of warm-blooded Lamniformes, previous researchers came up with a general model for the megalodon behemoths. Scientists believed this meant that the megalodon belonged to the Lamniformes order.

Great white sharks belong to the Lamnidae family, or lamnids, as do longfin and shortfin mako, porbeagle and salmon sharks. The new study examined whether these five species differ in shape from the rest of the order, which includes sharks that are cold-blooded. They also compared the five species to each other and to the rest of the Lamniformes order. Based on detailed drawings from the field, they made quantitative comparisons of their fins, heads and body shapes.

The authors did not find any general pattern among the body-shape differences. “Warm-bloodedness does not make you a differently shaped shark,” Sternes said.

“This new study shows that there are currently no scientific means to support or refute the accuracy of any of the previously published body forms of O. megalodon. All previously proposed body forms of O. megalodon should be regarded as speculations from the scientific standpoint.”

“Any meaningful discussion about the body form of O. megalodon would require the discovery of at least one complete, or nearly complete, skeleton of the species in the fossil record,” study co-author Jake Wood said.

Instead of using actual organisms or photos to make comparisons, Sternes pioneered the use of two-dimensional drawings to compare specimens, some of which are hard to access.

“The purpose of field guides is to identify a species, so the drawings must be accurate representations,” he said. “It’s a technique widely used in biology and works well for sharks.” It can also be used to study snakes and birds, for example, and other specimens are difficult to collect.

The authors believe that, two-dimensionally, there is no relationship between warm- or cold-bloodedness and body form within the Lamniformes order.

“Although it is still possible that O. megalodon could have resembled the modern great white shark or lamnids, our results suggest that the two-dimensional approach does not necessarily decisively allow the body form reconstruction for O. megalodon,” said Wood.

“This study may appear to be a step backward in science,” said co-author and paleobiologist Kenshu Shimada of DePaul University. “But the continued mystery makes paleontology, the study of prehistoric life, a fascinating and exciting scientific field.”

Edited by Siân Speakman and Kristen Butler