The ability of animals to understand numbers might surprise more than one observer. From insects to mammals, this aptitude turns out to be far more widespread than one might imagine.
Research shows that many species possess an innate sense of quantities. This system, called the approximate number system (ANS), allows for quickly distinguishing quantities without precise counting. Bees, for example, use this mechanism to memorize the number of landmarks leading to nectar-rich flowers.
Crows can count out loud and understand the concept of zero.
Some animals go further in their understanding of numbers. Crows, in particular, are capable of producing a precise number of calls in response to stimuli. This ability, observed in few species, suggests a form of counting more elaborate than simple ANS.
Studies on primates and parrots reveal even more advanced skills. Alex, an African grey parrot, could manipulate numbers and perform simple additions. These cases, however, remain exceptional.
The difference between ANS and human counting lies in the understanding of symbols and their order. While ANS allows for quick estimations, human counting requires lengthy learning. This distinction explains why so few animals truly master numbers.
What is the approximate number system (ANS)?
The ANS is a cognitive mechanism that allows animals to quickly estimate quantities without precise counting. It relies on specialized neurons called 'number neurons' that respond to specific quantities.
This system is present from birth in some species, like chicks, suggesting an innate basis. It makes it easier to distinguish distant numbers, like 4 and 8, than close numbers, like 7 and 8.
The ANS follows Weber's law, which states that the perception of differences depends on ratios rather than absolute values. This characteristic explains why animals perform better with small numbers.
Despite its limitations, the ANS offers a major evolutionary advantage, particularly for food searching or predator avoidance. It represents a form of adaptive intelligence shared by many species.
How do animals use numbers in their daily lives?
Animals exploit their sense of numbers in various contexts, from hunting to reproduction. Lionesses, for example, assess the number of roars from a rival pride before deciding to attack or flee.
Nephila clavipes spiders keep track of the number of insects trapped in their web. This ability allows them to optimize their hunting effort based on their environment's richness.
In túngara frogs, males use sound sequences to attract females. These acoustic duels, where each male adds an extra sound, illustrate a sophisticated use of numbers in communication.
These few examples show that the sense of enumeration is an essential skill for survival and reproduction in the animal world.