Crows and several other species belonging to the Corvidae family are famous for their intelligence within birds, with individuals from particular species observed using tools to access their favourite resource. But how smart crows really are, and how they got to be this smart🤔?
𝐶𝑜𝑟𝑣𝑢𝑠 𝑚𝑎𝑐𝑟𝑜𝑟ℎ𝑦𝑛𝑐ℎ𝑜𝑠 (Wagler, 1827), known as the large-billed crow or jungle crow, one of the 34 species of crows, is commonly found across Asia, from North-Eastern China to Indonesia🐦⬛. This species is omnivorous, eating nuts, seeds, dead animals and also hunts small animals like lizards. In cities, crows will scavenge, tearing rubbish bags open in search of food scraps🍖.
They live in flocks consisting of hundreds of individuals, and communicate with each other with their calls. Sociality is a factor often promoting the evolution of more complex brain functions, potentially contributing to the intelligence observed in crows today. This allowed them to use tools, develop long-term memories, and form complex social relationships. Unsurprisingly, they have the largest brain to body ratio among birds, but it takes more than that to explain their intelligence🧠. Like humans, crows spend a long period living with their parents, and even after they become independent they still live in large, complex social groups, which sometimes contain non-family members. This gives them plenty of opportunities to learn important skills from their parents and groupmates🧐.
Jungle crows especially are very social creatures and form relationships within their groups. They recognise each other’s appearance and calls, and such calls are passed down through generations, being even unique to a particular geographic region. They will form social hierarchies within their groups, preventing fights when foraging, with a submissive crow letting a dominant crow take food first🙇. When their friends or family members are losing a fight with another crow, they will provide support and help them out. These social interactions may be where their remarkable intelligence comes from🎓.
Jungle crows may be able to recognise their friends but other crow species can also recognise their enemies. If you have offended an American crow (𝘊𝘰𝘳𝘷𝘶𝘴 𝘣𝘳𝘢𝘤𝘩𝘺𝘳𝘩𝘺𝘯𝘤𝘩𝘰𝘴, Brehm, 1822), it would memorize your face and scold or even attack you in the future🥊. What’s more, the crow will warn its friends and family members about you, resulting in a familial grudge that could last for decades. Unless you want to be harassed by crows for years, we’ll recommend treating them with respect and to be nice to them.
Some crows are even capable of doing something many humans struggle with: self-control. When given a choice between a small, instant reward (some food) and waiting to swap for a greater reward (food they prefer), Carrion crows (𝐶𝑜𝑟𝑣𝑢𝑠 𝑐𝑜𝑟𝑜𝑛𝑒, Linnaeus, 1758) are able to control their impulses and trade for the preferred food. This ability to control their impulses is related to the ability to set future goals and making complex decisions, which further demonstrates their intelligence🎓.
The intelligence and the generalist diet of crows means they are not limited to forests, and can thrive in newer environments such as cities as well. Urban crows have been found snatching food from people near snack stalls, or even eating small pieces of plastic bags and aluminium foil when scavenging in garbage bags. This has led to an accumulation of toxic dioxin in their livers, causing thyroid gland diseases😵. Though living in cities presents its challenges, crows learnt to take advantage of it. Jungle crows have been seen building their nests on street poles using wire hangers, and placing walnuts on roads to use oncoming cars as nutcrackers. This shows just how adaptable and intelligent these birds are💪!
Come to the Hong Kong Biodiversity Museum to salute our crow specimens; no risks for offense here😉!
Text: Elgar
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