Crows are self-aware just like us, says new study

Crows have their own version of the human cerebral cortex.

crow in tree
Credit: Amarnath Tade/ Unsplash
  • Crows and the rest of the corvid family keep turning out to be smarter and smarter.
  • New research observes them thinking about what they've just seen and associating it with an appropriate response.
  • A corvid's pallium is packed with more neurons than a great ape's.

    • It's no surprise that corvids — the "crow family" of birds that also includes ravens, jays, magpies, and nutcrackers — are smart. They use tools, recognize faces, leave gifts for people they like, and there's even a video on Facebook showing a crow nudging a stubborn little hedgehog out of traffic. Corvids will also drop rocks into water to push floating food their way.

      What is perhaps surprising is what the authors of a new study published last week in the journal Science have found: Crows are capable of thinking about their own thoughts as they work out problems. This is a level of self-awareness previously believed to signify the kind of higher intelligence that only humans and possibly a few other mammals possess. A crow knows what a crow knows, and if this brings the word sentience to your mind, you may be right.

      Action-packed pallia

      Credit: Neoplantski/Alexey Pushkin/Shutterstock/Big Think

      It's long been assumed that higher intellectual functioning is strictly the product of a layered cerebral cortex. But bird brains are different. The authors of the study found crows' unlayered but neuron-dense pallium may play a similar role for the avians. Supporting this possibility, another study published last week in Science finds that the neuroanatomy of pigeons and barn owls may also support higher intelligence.

      "It has been a good week for bird brains!" crow expert John Marzluff of the University of Washington tells Stat. (He was not involved in either study.)

      Corvids are known to be as mentally capable as monkeys and great apes. However, bird neurons are so much smaller that their palliums actually contain more of them than would be found in an equivalent-sized primate cortex. This may constitute a clue regarding their expansive mental capabilities.

      In any event, there appears to be a general correspondence between the number of neurons an animal has in its pallium and its intelligence, says Suzana Herculano-Houzel in her commentary on both new studies for Science. Humans, she says, sit "satisfyingly" atop this comparative chart, having even more neurons there than elephants, despite our much smaller body size. It's estimated that crow brains have about 1.5 billion neurons.

      Fun with Ozzie and Glenn

      two crows in a tree

      Ozzie and Glenn not pictured

      Credit: narubono/Unsplash

      The kind of higher intelligence crows exhibited in the new research is similar to the way we solve problems. We catalog relevant knowledge and then explore different combinations of what we know to arrive at an action or solution.

      The researchers, led by neurobiologist Andreas Nieder of the University of Tübingen in Germany, trained two carrion crows (Corvus corone), Ozzie and Glenn.

      The crows were trained to watch for a flash — which didn't always appear — and then peck at a red or blue target to register whether or not a flash of light was seen. Ozzie and Glenn were also taught to understand a changing "rule key" that specified whether red or blue signified the presence of a flash with the other color signifying that no flash occurred.

      In each round of a test, after a flash did or didn't appear, the crows were presented a rule key describing the current meaning of the red and blue targets, after which they pecked their response.

      This sequence prevented the crows from simply rehearsing their response on auto-pilot, so to speak. In each test, they had to take the entire process from the top, seeing a flash or no flash, and then figuring out which target to peck.

      As all this occurred, the researchers monitored their neuronal activity. When Ozzie or Glenn saw a flash, sensory neurons fired and then stopped as the bird worked out which target to peck. When there was no flash, no firing of the sensory neurons was observed before the crow paused to figure out the correct target.

      Nieder's interpretation of this sequence is that Ozzie or Glenn had to see or not see a flash, deliberately note that there had or hadn't been a flash — exhibiting self-awareness of what had just been experienced — and then, in a few moments, connect that recollection to their knowledge of the current rule key before pecking the correct target.

      During those few moments after the sensory neuron activity had died down, Nieder reported activity among a large population of neurons as the crows put the pieces together preparing to report what they'd seen. Among the busy areas in the crows' brains during this phase of the sequence was, not surprisingly, the pallium.

      Overall, the study may eliminate the layered cerebral cortex as a requirement for higher intelligence. As we learn more about the intelligence of crows, we can at least say with some certainty that it would be wise to avoid angering one.

      A landslide is imminent and so is its tsunami

      An open letter predicts that a massive wall of rock is about to plunge into Barry Arm Fjord in Alaska.

      Image source: Christian Zimmerman/USGS/Big Think
      Surprising Science
      • A remote area visited by tourists and cruises, and home to fishing villages, is about to be visited by a devastating tsunami.
      • A wall of rock exposed by a receding glacier is about crash into the waters below.
      • Glaciers hold such areas together — and when they're gone, bad stuff can be left behind.

      The Barry Glacier gives its name to Alaska's Barry Arm Fjord, and a new open letter forecasts trouble ahead.

      Thanks to global warming, the glacier has been retreating, so far removing two-thirds of its support for a steep mile-long slope, or scarp, containing perhaps 500 million cubic meters of material. (Think the Hoover Dam times several hundred.) The slope has been moving slowly since 1957, but scientists say it's become an avalanche waiting to happen, maybe within the next year, and likely within 20. When it does come crashing down into the fjord, it could set in motion a frightening tsunami overwhelming the fjord's normally peaceful waters .

      "It could happen anytime, but the risk just goes way up as this glacier recedes," says hydrologist Anna Liljedahl of Woods Hole, one of the signatories to the letter.

      The Barry Arm Fjord

      Camping on the fjord's Black Sand Beach

      Image source: Matt Zimmerman

      The Barry Arm Fjord is a stretch of water between the Harriman Fjord and the Port Wills Fjord, located at the northwest corner of the well-known Prince William Sound. It's a beautiful area, home to a few hundred people supporting the local fishing industry, and it's also a popular destination for tourists — its Black Sand Beach is one of Alaska's most scenic — and cruise ships.

      Not Alaska’s first watery rodeo, but likely the biggest

      Image source: whrc.org

      There have been at least two similar events in the state's recent history, though not on such a massive scale. On July 9, 1958, an earthquake nearby caused 40 million cubic yards of rock to suddenly slide 2,000 feet down into Lituya Bay, producing a tsunami whose peak waves reportedly reached 1,720 feet in height. By the time the wall of water reached the mouth of the bay, it was still 75 feet high. At Taan Fjord in 2015, a landslide caused a tsunami that crested at 600 feet. Both of these events thankfully occurred in sparsely populated areas, so few fatalities occurred.

      The Barry Arm event will be larger than either of these by far.

      "This is an enormous slope — the mass that could fail weighs over a billion tonnes," said geologist Dave Petley, speaking to Earther. "The internal structure of that rock mass, which will determine whether it collapses, is very complex. At the moment we don't know enough about it to be able to forecast its future behavior."

      Outside of Alaska, on the west coast of Greenland, a landslide-produced tsunami towered 300 feet high, obliterating a fishing village in its path.

      What the letter predicts for Barry Arm Fjord

      Moving slowly at first...

      Image source: whrc.org

      "The effects would be especially severe near where the landslide enters the water at the head of Barry Arm. Additionally, areas of shallow water, or low-lying land near the shore, would be in danger even further from the source. A minor failure may not produce significant impacts beyond the inner parts of the fiord, while a complete failure could be destructive throughout Barry Arm, Harriman Fiord, and parts of Port Wells. Our initial results show complex impacts further from the landslide than Barry Arm, with over 30 foot waves in some distant bays, including Whittier."

      The discovery of the impeding landslide began with an observation by the sister of geologist Hig Higman of Ground Truth, an organization in Seldovia, Alaska. Artist Valisa Higman was vacationing in the area and sent her brother some photos of worrying fractures she noticed in the slope, taken while she was on a boat cruising the fjord.

      Higman confirmed his sister's hunch via available satellite imagery and, digging deeper, found that between 2009 and 2015 the slope had moved 600 feet downhill, leaving a prominent scar.

      Ohio State's Chunli Dai unearthed a connection between the movement and the receding of the Barry Glacier. Comparison of the Barry Arm slope with other similar areas, combined with computer modeling of the possible resulting tsunamis, led to the publication of the group's letter.

      While the full group of signatories from 14 organizations and institutions has only been working on the situation for a month, the implications were immediately clear. The signers include experts from Ohio State University, the University of Southern California, and the Anchorage and Fairbanks campuses of the University of Alaska.

      Once informed of the open letter's contents, the Alaska's Department of Natural Resources immediately released a warning that "an increasingly likely landslide could generate a wave with devastating effects on fishermen and recreationalists."

      How do you prepare for something like this?

      Image source: whrc.org

      The obvious question is what can be done to prepare for the landslide and tsunami? For one thing, there's more to understand about the upcoming event, and the researchers lay out their plan in the letter:

      "To inform and refine hazard mitigation efforts, we would like to pursue several lines of investigation: Detect changes in the slope that might forewarn of a landslide, better understand what could trigger a landslide, and refine tsunami model projections. By mapping the landslide and nearby terrain, both above and below sea level, we can more accurately determine the basic physical dimensions of the landslide. This can be paired with GPS and seismic measurements made over time to see how the slope responds to changes in the glacier and to events like rainstorms and earthquakes. Field and satellite data can support near-real time hazard monitoring, while computer models of landslide and tsunami scenarios can help identify specific places that are most at risk."

      In the letter, the authors reached out to those living in and visiting the area, asking, "What specific questions are most important to you?" and "What could be done to reduce the danger to people who want to visit or work in Barry Arm?" They also invited locals to let them know about any changes, including even small rock-falls and landslides.

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