martes, 21 de julio de 2015

3 ways ravens are among the smartest animals on the planet


Photo: Teri Franzen/MNN Flickr Group 
1) Ravens can keep track of the social status of other ravens both in their own group and in groups of unfamiliar ravens.
This is a useful strategy particularly if a raven has any plans to leave their own group and join another — they'll know just where they fit in the pecking order and also who to be submissive to in order to work their way into the group.

Researchers discovered this by experimenting with playing conversations between ravens to a subject raven, conversations that reversed the social ranking that the subject raven was familiar with.

IFLScience writes, "They found that ravens paid especial attention and seemed stressed -- displaying behaviors like head turns and body shakes -- when they hear playbacks that simulate a rank reversal in their group. They just didn’t expect a low-ranking bird to show off to a higher-ranking one -- this violates their rank relations. They were fine when the dominance structure in the playback reflects their hierarchy accurately. The ravens also responded to simulated rank reversals in neighboring groups, suggesting that they’ve figured out who’s boss among unknown birds just by watching and listening to them (since there was no physical contact between groups). It’s the first evidence of animals tracking rank relations of individuals that don’t belong to their own group -- a useful skill for a bird switching foraging units."

So, ravens learn social ranks well enough to even figure out what's what in foreign groups of ravens with whom they've never actually interacted. In other words, ravens are savvy politicians.

2) Ravens can remember individual human faces.
Researchers have experimented with wearing masks while trapping and tagging crows (extremely close relatives to ravens and also shockingly intelligent). They wore a particular mask when trapping and releasing crows, and then had another neutral mask that wasn't used when trapping. They discovered that crows learned and recognized the "face" of the trapper. And not only that — they teach their offspring and other group members just who is who so that their friends and family could avoid being trapped by the masked person.

The New York Times writes, "In the months that followed [the trapping and tagging], the researchers and volunteers donned the masks on campus, this time walking prescribed routes and not bothering crows. The crows had not forgotten. They scolded people in the dangerous mask significantly more than they did before they were trapped, even when the mask was disguised with a hat or worn upside down. The neutral mask provoked little reaction. The effect has not only persisted, but also multiplied over the past two years. Wearing the dangerous mask on one recent walk through campus, Dr. Marzluff said, he was scolded by 47 of the 53 crows he encountered, many more than had experienced or witnessed the initial trapping. The researchers hypothesize that crows learn to recognize threatening humans from both parents and others in their flock."

3) Ravens can solve puzzles.
Ravens have incredible problem-solving skills. In some experiments, they are presented with a new puzzle, which they study for a bit and then speedily solve.

Science Blogs writes about one set of experiments by researchers Bernd Heinrich and Thomas Bugnyar, "They found that some adult birds would examine the situation for several minutes and then perform this multistep procedure in as little as 30 seconds without any trial and erroras if they knew exactly what they were doing. Because there was no opportunity for the birds to be confronted with a similar problem in the wild, the simplest explanation is that they were able to imagine the possibilities and to perform the appropriate behaviors. The authors also found that successfully performing this behavior required maturity: immature birds were unable to do it while year-old birds performed a variety of trials before they were able to succeed."

So not only can they figure out puzzles surprisingly quickly, but they learn from past experience to build on their conclusions about how to get what they want. In this PBS video, a raven figures out how to pull up a fishing line to steal the catch.



This is just the tip of the iceberg when it comes to how ravens have displayed their intelligence and strategizing abilities. If you'd like to learn more, check out the book In the Company of Crows and Ravens. By the time you finish the last page, you'll never look at ravens in the same way again.


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Jaymi Heimbuch is a writer and photographer at Mother Nature Network. Follow her on Twitter, Google+ and Facebook.



ORIGINAL: Mother Nature Network
Jaymi Heimbuch
January 26, 2015

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