• Like humans, whales and monkeys pick up feeding habits from friends

    Erica van der Waal

    Adults and a vervet monkey baby snack on corn kernels dyed pink.

    By Nidhi Subbaraman

    Humans aren't the only species swayed by fashion trends and peer pressure. Two newly published studies say vervet monkeys and humpback whales learn eating preferences and feeding techniques from their social groups, too.

    Erica van de Waal, a researcher at Scotland's University of St. Andrews, trained four groups of wild vervet monkeys to choose their meals from different colors of dyed corn. In some groups, buckets of blue corn were mixed with a bitter-tasting additive, so the monkeys in that group snacked on the pink kernels. In others, the bitter flavoring was swapped, so monkeys ate only the blue corn.

    Here's the big question: Would vervet monkey babies pick up the corn color preference from their mothers? Once new broods of babies started eating solid food, the bucket pairs with color-separated kernels were reintroduced. This time, there was no bitter additive in either bucket. Still, the mums went back to eating the corn they remembered tasted good. Twenty-six of the 27 babies, without trying to experiment, followed suit.

    But when the monkeys traveled to other groups, with different eating habits, many picked up the local favorites. Ten wandering males, in search of mates, found themselves in the awkward company of a group that ate a different colored type of corn. Without missing a beat, all but one of them smoothly switched to the local flavor — the very first time they ate from the tub. 

    The researchers describe the choice as a "When in Rome ..." impulse. It's possible the males switched to the local chow because they didn't want to stick out as newbies, and it might have helped win the favor of the females they'd eventually try to court, the group explained in a paper published in this week's issue of the journal Science.

    Frans de Waal, a primatologist at Emory University, said the results of the studies were "striking," particularly because the primate research community had never seen something like the the double-dyed corn study before. "It hints at a level of conformism that most of us had not held possible," he wrote to NBC News in an email, and suggests that "primates are much more cultural creatures than [other] small-scale experiments thus far have indicated."

    Jennifer Allen/Whale Center of New England

    Lunch time for a humpback whale.

    Off the coast of New England, humpback whales have also shown evidence of social learning. 

    When stock of their favorite herring crashed, whales in that area switched to gulping down schools of sand lance. Possibly to help gather the fish, they slapped the surface of the water with a tail fluke, and then dove underneath and blew bubbles into the school before lunging to swallow. Scientists who have been watching the whales for 27 years found that the tail-flicking habit has caught on in other whale groups. Whale behavior experts at the University of St. Andrews parsed decades' worth of observational data from 650 humpbacks, and traced the spread of this unique "lobtail" feeding trick through the whale groups.

    Jennifer Allen, the first author of the study published in Science, confessed that the dataset is older than she is. "We have a chronological sequence of what each whale is doing and when," she told NBC News. "It's a very complete written picture of what the scientists were looking at at the time." 

    It isn't clear why lobtail feeding is so popular among humpbacks. Allen said they haven't noticed that lobtail feeders are any healthier or having more babies. They seem to have picked up the trick from each other just because they could. There was only one explanation: "No matter how you slice it, the only model that fit this data well was social learning," she said. 

    "These kinds of studies give us ideas about the mechanism that are involved in the acquisition of new behavior," Diana Reiss, a professor at Hunter College who studies cognition in dolphins and marine mammals, told NBC News. "They're watching the other humpbacks around them and learning by observing others in their peer group," rather than learning from their mothers, or being genetically wired to feed that way. 

    Beyond explaining animal behavior, these findings have some implications for how people have traditionally understood human culture.

    "Although our behavior is very distinctive, it didn't appear from nowhere — it has some very ancient roots," Andrew Whiten, who led the vervet monkey study, told NBC News. The usual assumption is that "we are the cultural species par excellence on the planet," he said, "but that didn't come out of the blue. We share some of that — that wanting to learn from others — with our primate relatives as well, and larger groups of mammals and maybe birds."

    In addition to Whiten and van de Waal, the authors of "Potent Social Learning and Conformity Shape a Wild Primate's Foraging Decisions" include Christele Borgeaud.

    In addition to Allen, the authors of "Network-Based Diffusion Analysis Reveals Cultural Transmission of Lobtail Feeding in Humpback Whales" include Mason Weinrich, Will Hoppitt and Luke Rendell.

    Nidhi Subbaraman writes about science and technology. Follow her on Twitter and Google+. 

  • Religious norms may alter animal life in Amazon

    Jose Fragoso / Courtesy of Stanford University

    Two Wapishana women maintain traditional rock carvings at a spiritual site.

    By Megan Gannon
    LiveScience

    Religious and cultural norms often dictate which animals should be protected, eaten or avoided at all costs. Islam prohibits consuming pork; cows are considered sacred by Hindus; and most Americans squirm at the idea of eating a horse. These varying taboos and customs can change the faunal landscape around certain groups of people.

    Researchers from Stanford University investigated how three Christian influences — evangelical, Sabbatarian and Roman Catholic/Anglican — may have altered animal treatment among converted indigenous communities in the Amazon. It turns out that missionaries might not only be changing hearts and minds in the region, but also biodiversity, the researchers say.

    Though people of the Makushi and Wapishana tribes have traditionally believed that consuming lowland tapir meat can make them sick, many of them eat the animal anyway, trusting that their shamans will cure the potential illness. But people in the tribes who converted to one of the Sabbatarian faiths, such as such as Seventh-Day Adventism, and strongly rejected shamanism were much less likely to eat tapir, because their new religion made doing so taboo, the researchers found in their survey of 9,900 individuals in the Amazon. [The Awá: Faces of a Threatened Tribe]

    While the new religions might mean fewer tapirs are killed, getting rid of shamanism, especially among evangelical and Sabbatarian groups, seems to have hit animals that once enjoyed protection under the indigenous leaders, the researchers say. Shamans often guarded and discouraged hunting in areas of land thought to be swarming with powerful spiritual entities.

    "Based on field observations, I think that the removal of shamans has translated into more killing of animals," José Fragoso, a scientist at Stanford University, said in a statement. "Our perception is that they are killing more animals that are not taboo, such as pigs, and also that they are making kills in the holy areas, which were previously off-limits."

    Fragoso and his colleagues, whose research is funded by the National Science Foundation, plan to investigate whether some animals are being killed in greater numbers, according to Stanford University. Their most recent findings were published last year in the journal Human Ecology.

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  • Chimps learn tool use by watching others, study finds

    Yamamoto S, Humle T, Tanaka M (2013) Basis for Cumulative Cultural Evolution in Chimpanzees: Social Learning of a More

    Like humans, chimpanzees display the ability to learn techniques by watching others.

    By Tanya Lewis
    LiveScience

    Chimpanzees can learn to use tools more efficiently by watching how others use them, new research suggests. The findings help illuminate ways that culture could evolve in nonhuman animals.

    "Social learning is very important to maintaining a culture," study researcher Shinya Yamamoto of Kyoto University in Japan told LiveScience. "For example, in humans, we can develop technologies based on previous techniques, and other people can learn the more efficient techniques by accumulating cultural knowledge." The new research provides insight into how cultural evolution might occur in chimpanzees.

    In the study, nine captive chimpanzees at the Primate Research Institute at Kyoto University were presented with a straw-tube they could use to obtain juice from a bottle through a small hole. Of their own accord, the chimps used one of two techniques to get the juice: "dipping" and "straw-sucking." The dipping technique involved inserting the straw into the juice and removing it to suck on the end, whereas straw-sucking entailed sipping the juice through the straw. Straw-sucking was a much more efficient means of getting juice than dipping.

    Five of the chimps initially used the dipping method and four used the straw-sucking method. The researchers then paired each of the five chimps who used dipping with a chimp who was a straw-sucker. Four of the dippers switched to straw-sucking after observing the other animal using the more effective technique. The fifth dipper switched too, but only after watching a human using it. [ See video of the chimps.]

    Chimps who paid the most attention to the straw-sucking demonstrator switched to the new method more rapidly. After switching, the animals never reverted to the dipping method.

    The apes' adoption of the straw-sucking technique shows social learning, the researchers say. The chimpanzees who were dippers "didn't learn the sucking technique by themselves, only when they are paired with the sucking individual," Yamamoto said. The one chimp that didn’t adopt the new technique right away may have been subordinate to her partner chimp, Yamamoto said. As soon as Yamamoto demonstrated the technique, however, the chimp started using it.

    The results contrast with the findings of previous studies, which have shown that chimpanzees don't always adopt an improved technique used by others. One explanation may be that unlike in previous studies, the better technique (straw-sucking) was no more physically or mentally difficult to perform than the original technique (dipping), the researchers said. Additionally, the chimpanzees in previous studies seemed satisfied with using their original technique, whereas these chimps may not have been content with their method's efficiency, the researchers added.

    This study and others like it "add to the idea that the apes are very well capable of social learning," primatologist Frans de Waal of Emory University in Atlanta told LiveScience.

    Scientists have debated for decades about whether or not animals have culture. "We cannot hold chimpanzees against the standard of modern-day human culture," de Waal, who was not involved with the research, said, but "the border is much grayer than we thought."

    The study was published online Wednesday in the journal PLOS ONE.

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