They Know Who You Are: How City Animals Recognize People

In the heart of the city, dominated by human-made material, animals face more than cars and concrete—they face humans. And to survive, some of them have developed a surprising skill: reading human behaviour and recognizing people. They learn who feeds them, who ignores them, and most importantly, who poses a threat to them. They need to be able to distinguish the dangerous from the non-dangerous humans. This way urban animals can reduce overreacting (and associated costs) to innocent stimuli, while still reacting to genuinely threatening stimuli.

Remember the good and the bad ones

Some urban birds like the feral pigeon (Columba livia) have learned to distinguish neutral from hostile humans by assessing the threat and respond accordingly. They use stable individual characteristics to distinguish one human from the other and recognize them. Pigeons used this knowledge learned from interactions with humans to maximize the profitability of the urban environment (Belguermi et al. 2011).

American crows (Corvus brachyrhynchos) take recognizing familiar faces to a whole other level. They quickly and accurately learn to recognize the face of a dangerous person and continue to do so for at least two and a half years. They scold and mob individual people that had wronged (e.g., trapped) the birds in the past, even when these people were among a crowd. What is even more impressive is that the crows recognize people even when they are wearing a mask while they didn’t at the time of the wrongdoing, and vice versa. Crows and other birds are even able to recognize faces upside down, something that mammals are less capable of (Marzluff et al. 2010).

Responding to human behaviour

Magpies (Pica pica) have a faster risk assessment when the approaching person looks directly at the bird, regardless of the perceived risk. The decision to continue foraging or to fly away when the person approaches is faster when the person makes eye contact with the bird. The direct gaze reveals more information about the person’s intentions , enabling the magpie to respond more quickly. This fast threat assessment is vital in a city where life moves fast, humans are everywhere and behave unpredictably. If you’re too slow and you might get killed, or if you’re too fast you stress about nothing (Lee et al. 2013).

Another important cue for risk perception is irregular behaviour, especially when combined with direct gaze. Squirrels in the metropole of New York City usually pay little attention to humans. As long as humans that pass by stay on the footpath and don’t look directly at the squirrels, the squirrels mostly ignore the passerby. However, if the human deviate from the path and looked at the squirrel, almost all of the squirrels run away. Squirrels are thus desensitized to human activity, as long as humans perform predictable behaviour, such as staying on the footpath. This adaptation reduces unnecessary escape responses, saving energy and increasing the ability of the squirrels to live in the busy urban environment (Bateman and Fleming 2014).

Identifying individual humans and judging their intentions is not only important to avoid harm or unnecessary loss of energy. It can also yield food or help from humans. A person that has fed or helped an animal before is more likely to do that again than another random person. Identifying that person and “befriending” them can give an animal resources that would otherwise cost more energy if they had to acquire it themselves. Especially in the fast-paced chaotic urban jungle, knowing who to trust—and who to avoid—can make all the difference.

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References

Belguermi A., Bovet D., Pascal A. et al., 2011 – Pigeons discriminate between human feeders. Anim Cogn 14, 909–914. https://doi.org/10.1007/s10071-011-0420-7

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, Issue 3, 699-707. https://doi.org/10.1016/j.anbehav.2009.12.022

Lee S., Hwang S., Joe Y. et al., 2013 – Direct look from a predator shortens the risk-assessment time by prey. PLOS one. https://doi.org/10.1371/journal.pone.0064977

Baterman P.W. and Fleming P.A., 2014 – Does human pedestrian behaviour influence risk assessment in a successful mammal urban adapter? Journal of Zoology 294, Issue 2, 93-98. https://doi.org/10.1111/jzo.12156

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Featured image: “Large-billed Crow (Wild Crow) Hiledole Height Tarkeshwor Municipility Kathmandu Nepal Rajesh Dhungana (7)” by Rajesh Dhungana. https://openverse.org/image/a51e46ef-efad-489a-b9ec-b910e3d8adb9?q=crow+stare&p=29