Why Crows Are as Smart as 7 Year Old Humans

In 2014 New Caledonian crows were presented with various tubes filled with water with a treat floating on top which they couldn’t quite reach where the crows knew to drop rocks into the water-filled tube to raise the water level to reach the treat and ignored the tube with sand where the authors believe that their skill level at deciphering and completing these tasks is similar to five to seven year old children demonstrating how corvid problem-solving capabilities rival young human cognitive development representing convergent evolution of intelligence across distant taxonomic groups.

New Caledonian crows can build tools and not just simple ones but ones with multiple parts where when given objects that were too short to retrieve food from a puzzle box the crows combined elements by inserting one stick into the hollowed opening of another to make a tool long enough to reach the food where one crow even made three and four part tools demonstrating how compound tool construction represents hierarchical planning and mental representation abilities previously associated exclusively with human and great ape cognition.

In a study published in 2020 New Caledonian crows were first shown one of three puzzle boxes that they already knew how to open each requiring a specific tool where after selecting an object and waiting 10 minutes they were allowed back into the test area where the researchers discovered that not only did the birds choose the correct tool that would open the corresponding puzzle box but they would remember to bring the tool with them demonstrating how episodic memory and future planning enable corvids to make present decisions based on anticipated future needs matching cognitive abilities emerging in 5-year-old human children.

Birds and mammals split on the evolutionary tree 320 million years ago where before the evolutionary split both birds and mammals evolved a large pallium but after their lineages split the mammalian pallium evolved into a layered structure known as the cerebral cortex while birds don’t have a cerebral cortex but a study published in 2020 found that the fibers and circuitry in the bird pallium are organized very similarly to a mammalian neocortex demonstrating how convergent evolution produced functionally equivalent neural architectures through radically different developmental pathways enabling comparable cognitive capabilities across distantly related vertebrate lineages.

In a 2016 study researchers measured the number of neurons in various bird and primate species where they found that some birds like corvids have twice as many neurons as primates with similar sized brains with numbers closer to that of larger primates demonstrating how tightly packed neurons lead to better communication between them enabling corvids to achieve primate-level intelligence despite dramatically smaller absolute brain size representing efficiency advantage through miniaturization and dense packing.

One theory is that corvid intelligence has to do with the way they are raised where unlike other species corvids spend more time with their parents where New Caledonian crows are fed by their parents for up to two years where during this time they have ample access to role models who are making and using tools and have the opportunity to use these tools themselves demonstrating how extended parental care enables cultural transmission of complex skills through observational learning creating cumulative knowledge transfer across generations.

Adult corvids may rarely live in wide social groups but often juveniles do where before pairing up with a mating partner during their teenage years some species of corvids live in larger flocks aptly called juvenile gangs where these gangs work exactly like they sound where a bunch of teenagers hang out and bully each other and fight where in these angsty years corvids like ravens for example form the many relationships that they have to keep tabs on demonstrating how adolescent social complexity drives intelligence development through relationship management and social navigation comparable to primate juvenile socialization patterns.

Outside of Yellowstone National Park certain ravens have been seen interacting with wolves especially wolf pups where the animals have been seen playing tug of war and the ravens tease and entice the puppies to jump and grab sticks where sometimes the ravens will even pull the wolves tails where by all accounts it looks like the animals are playing where some scientists think that individual ravens may even develop special bonds with individual wolves within a pack demonstrating how corvid social intelligence extends beyond conspecifics enabling mutualistic interspecies relationships that provide scavenging benefits through bond formation and cooperative play.

This propensity to interact with other species has some groups wondering how we may be able to cooperate with corvids where one idea is to train crows and other corvids to pick up cigarette butts or garbage where a few different companies are developing devices that will autonomously train the birds giving them a treat once they place the trash into the device demonstrating how corvid intelligence and trainability enable practical human-wildlife cooperation through operant conditioning creating environmental benefits while leveraging natural problem-solving abilities for anthropogenic waste management.