A recent study – and one which I would argue is pretty important – discovered that crows can hold grudges for 17 years. They hold grudges against people who have maligned them; who have been harmful to them and who they don’t trust because of experiences and interactions that they have had with these people. They hand down their grudge to other family members and through a generation. Crows typically have a lifespan of about 7 to 8 years in the wild, but they can live significantly longer under optimal conditions. Some individuals have been known to live up to 20 years or more, particularly in captivity where they are protected from predators and have a consistent food supply. Factors such as environmental conditions, predation, and availability of food can all influence their lifespan in the wild.
Crows are very intelligent. We know that. There are other intelligent animals such as elephants, dolphins and primates to name three species and I would argue that these animals are also able to hold grudges for a long time. Humans should be cognisant of this and recognise that many animals are like humans in many respects. Once we realise that we should treat them with more respect, I hope.
In the crow study, Professor John Marzluff wore an ogre mask to capture crows and thereafter he monitored their displeasure. He was very patient. He works out of the University of Washington as an environmental scientist.
More: Crows can count back numbers through vocalisations (infographic)
He wore that mask while capturing seven crows in a net and attaching identification bands to them. He set them free unharmed but the event was traumatic for the crows and they remembered it and held a grudge against him for 17 years. This is a very patient scientist. He is preparing to publish his findings.
It also appears that crows are able to recognise facial features. When researchers wore neutral masks and fed the crows without subjecting them to trauma they did not hold a grudge.
In other experiments, volunteers wore various types of mask some looking dangerous while others were neutral. One volunteer who donned a dangerous mask said that, “The birds were really raucous, screaming persistently, and it was clear they weren’t upset about something in general. They were upset with me.”
Marzluff also conducted brain scans on the crows during his research and found that the brains of crows respond to fear in a similar way to humans. They have a region of the brain which is an analogous to the amygdala of mammals. This is the region of the vertebrate brain when negative associations are stored as memories.
Marzluff discovered that crows hold a grudge for 17 years because he persistently went back to test the reaction of the crows and “during one walk in September last year no scalding calls were lodged for the first time since the start of the experiment, 17 years after it began.” The words are those of Kaya Burgess, the science reporter of The Times. I am relying upon their report on Friday, November 1, 2024.
I have argued that it is reasonable to suggest that other intelligent animals might grudges for extended periods. Here’s some more on that. Crows are part of a small but growing list of animals—like dolphins, elephants, and certain primates—that display complex social cognition, including memory of individual faces and past interactions. In highly social animals, holding grudges can serve adaptive purposes, helping them navigate social hierarchies, avoid former aggressors, and enforce social norms.
For example:
- Elephants are known for their remarkable memory and have been observed to avoid areas or individuals associated with past traumatic events, even many years after the encounter.
- Dolphins have complex social relationships and may exhibit retaliatory behaviors toward individuals that have previously harmed them or a family member.
- Primates like chimpanzees and baboons also remember past negative interactions, which can influence social alliances and grooming behaviors for years.
The concept of holding a grudge might seem human, but in social animal groups, where relationships and interactions are key to survival, remembering negative encounters could be a way to maintain social stability and safety. So, while each species has unique social structures and cognitive capacities, it seems fair to think that long-term memory of past slights or threats might not be unique to crows and could be more widespread among intelligent, social animals.
