Crows fear death and assess risk by learning from the remains of other crows, according to a recent study in the journal of Animal Behaviour.
Researchers from the University of Washington showed that crows associate dead crows with danger and will remember people who they see near a dead crow for up to six weeks.
Learning about the risk of death from looking at the corpses of a dead member of the same species is something humans do routinely, according to the research.
Elephants, bottlenose dolphins and chimpanzees are among other species that gather around and touch their dead relatives, but the reasons behind the behaviour are not often studied.
The latest research looked at the behaviour of common urban crows that “mob” and squawk around the remains of dead crows.
The research “suggests that dead crows and predators are equivalent at triggering fear” among live crows.
In a series of experiments, crows were presented with a dead crow near their main food source. In some cases, the remains were accompanied with a person or a second predator, a red-tailed hawk.
When the crows found a dead crow near the food source, they were slower to approach to eat, even after the threat was removed.
If the crows spotted a human and a dead crow, a hawk and a dead crow or a hawk on its own near the food, they would hold off on approaching for up to 72 hours later.
Crows have a good ability for recognising individual humans, according to previous research quoted in the study, and can even recall the faces of people who captured them and are attentive to gaze.
In the cases where humans were involved, the study showed that crows will “scold” a human that they see holding a dead crow, by mobbing or diving. According to the researchers, the crows immediately “learned and remembered humans that were associated with danger”.
The person that appeared “complicit” in the crow’s death was scolded for up to six weeks after the exposure, in some cases.
Researchers highlighted the intelligence and complex social structures among crows, but also mentioned practical implications for humans.
Specifically, the study said people should “conceal” their identity when removing a crow’s remains and ensure there are “no visible crows present” to witness the act.