Crows and Aesop’s Fable: More fact than fiction?

In Aesop’s Fable, “The Crow and the Pitcher,” a thirsty crow finds a pitcher of water, but the water level is too low for him to reach. Instead of giving up, he drops stones into the pitcher to raise the water level until it’s high enough for him to drink. The funny thing about this fable? It’s actually fact.

“Crow” is a catch-all term for the family Corvidae, the corvids. This family–or grouping of animals–includes crows, ravens, jays, magpies, rooks, jackdaws, and others, and their cognitive capabilities rival those of primates. In addition to problem-solving like in Aesop’s fable, crows have a fantastic memory, especially when it comes to human faces.

Silhouette of an American crow. Photo credit: Ryane Logsdon

Dr. John Marzluff, a researcher at the University of Washington, caught and harassed some local American crows (Corvus brachyrhynchos) while wearing a caveman mask. Before Dr. Marzluff harassed these crows, they ignored people wearing the caveman mask, but afterward, they were aggressive towards anyone wearing it. They remembered this caveman’s misdeeds for years. The crows even lashed out at people wearing the mask upside down, though they left people wearing other masks alone – a Dick Cheney mask didn’t scare them one bit. Not only did the crows remember their own personal experiences with the caveman, information about this “dangerous” person seemed to spread throughout the population. The harassed crow and his kids displayed aggression toward the caveman mask, as well as other crows in the population who had never seen the original mask.

Masks used in facial recognition study. Figure adapted from Marzluff et al. 2010. — Masks used in the facial recognition study. Figure adapted from Marzluff et al. 2010.

New Caledonia. Map image from Google Maps.

On the top of the crow-cognition totem pole is the New Caledonian Crow (Corvus moneduloides), a tool-crafting mastermind only found on the island of New Caledonia. Studied primarily by Dr. Russell Gray and Dr. Gavin Hunt at the University of Aukland, these crows not only use, but also create tools to fish grub out of nooks and crannies in logs. While tool use is widespread among the animal kingdom, tool manufacture is much rarer, and is associated with high levels of intelligence. Even more incredibly, over time, the crows have improved upon the design of their tools to make them better, a trait previously thought to be unique to humans.

Maybe being a bird brain isn’t such a bad thing!

New Caledonian Crow. Image Copyright Jolyon Troscianko — New Caledonian Crow using a hooked twig to get grub. Image Copyright Jolyon Troscianko.

This video shows a New Caledonian Crow solving a 3-step puzzle for the first time:

If you want to see more, this video shows a more complex 8-step puzzle:

Sources:

Bird, C.D. & Emery, N.J. 2009. Rooks use stones to raise the water level to reach a floating worm. Current Biology 19.16:1410-1414.

Cornell, H.N., Marzluff, J.M., & Pecoraro, S. 2011. Social learning spreads knowledge about dangerous humans among American crows. Proceedings of the Royal Society of London B: Biological Sciences DOI:10.1098/rspb.2011.0957

Hunt, G.R. & Gray, R.D. 2003. Diversification and cumulative evolution in New Caledonian crow tool manufacture. Proceedings of the Royal Society of London B: Biological Sciences DOI: 10.1098/rspb.2002.2302

Marzluff, J.M., Walls, J., Cornell, H.N., Withey, J.C., & Craig, D.P. 2010. Lasting recognition of threatening people by wild American crows. Animal Behaviour 79: 699-707

Orenstein, R.I. 1972. Tool-Use by the New Caledonian Crow (Corvus moneduloides). The Auk 89.3:674-676 Article Stable URL: http://www.jstor.org/stable/4084273