A team of scientists has shown that crows can ‘count’ out loud – producing a specific and deliberate number of caws in response to visual and auditory cues. While other animals such as honeybees have shown an ability to understand numbers, this specific manifestation of numeric literacy has not yet been observed in any other non-human species.

The ability to count aloud is distinct from understanding numbers. It requires not only that understanding, but purposeful vocal control with the aim of communication. Humans are known to use speech to count numbers and communicate quantities, an ability taught young.

This competency in crows also mirrors toddlers’ enumeration skills before they learn to understand cardinal number words and may therefore constitute an evolutionary precursor of true counting where numbers are part of a combinatorial symbol system.