Shutterstock/Agus_Gatam
Sara I. Paisa
Bucharest, Romania
I am a keen birdwatcher and in the past year or so, I have observed that magpies and doves can recognise individual people. I have also read that other corvids have this ability too.
They go through a process of active learning. Initially, they tend to be afraid of humans. As time goes by, caution turns into curiosity, then into interest. We know that magpies are fond of shiny objects, so me seeing them near my window isn’t a surprise, especially during sunny days. The doves, I suspect, have a nest near my home, like the family of magpies, and go through the same process of recognising individuals. Both species are clearly capable of distinguishing me and my family from other people in this area.
On a trip to the Tower of London, I greeted one of its ravens with a simple “Hello!”. It tilted its head in the same way that dogs do when paying close attention to something, indicating that the raven was actively engaging with me.
“
Given the variety of sensory worlds they inhabit, animals may even use senses we would never expect to tell people apart
“
Francesca Cornero, Willa Lane and Nicky Clayton
University of Cambridge, UK
Studies and anecdotal evidence both suggest that most mammals – including great apes, dolphins, elephants, polar bears, dogs, cats, horses, sheep and pigs, among others – recognise individual people. Birds do as well, signs of which are found in a variety of species, although some of the most convincing scientific evidence has been from the parrot and corvid families. For example, in laboratory studies, crows have learned to identify the faces of threatening humans and they continue to mob them over years – even crows that hadn’t experienced the harassment learned to target the same humans.
Individual recognition isn’t limited to the mammalian or avian worlds, however. Octopuses sometimes spit water at people they dislike. Their cuttlefish cousins are also probably capable of recognising individual humans: one of us noted that a cuttlefish in a laboratory stopped reacting to a specific researcher who always moved quickly, but would ink or jet away if other people moved at the same fast pace. There is also evidence that fish such as archerfish and sea bream, reptiles like tokay geckos and corn snakes, and insects including honeybees and wasps can learn to recognise individual humans. This is probably a natural extension of their existing ability to discriminate between safe and unsafe features of the physical and social dynamics of their environment – for example, to categorise friends and foes.
As research continues, we will probably find even more species that are capable of recognising individual humans. Given the variety of sensory worlds they inhabit, they may even use senses we would never expect (or haven’t yet discovered!) to tell people apart.
To answer this question – or ask a new one – email lastword@newscientist.com.
Questions should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. We reserve the right to edit items for clarity and style. Please include a postal address, daytime telephone number and email address.
Â鶹´«Ã½ retains total editorial control over the published content and reserves all rights to reuse question and answer material that has been submitted by readers in any medium or in any format.
