It is often said that understanding numbers is a distinct attribute of human intelligence - a characteristic that sets us apart from other animals and language. However, that's not true.
Honeybees count landmarks when navigating toward sources of nectar. Red-backed salamanders can tell the difference between one, two, and three. Mosquitofish can manage up to four. Ring-tailed lemurs can also put groups of different numbers of objects in order of size. They can tell which group is larger, but only when one group is at least twice as big as the other.
Scientists have observed that practically every animal they have studied - insects and cephalopods, amphibians and reptiles, birds and mammals - can distinguish between sets of objects or sounds in sequence.
Counting helps animals survive
Counting is not unique to humans: a vast range of animals understand numbers that help them to solve a variety of problems, such as acquiring food, navigating, defending themselves, and even finding a mate. Honeybees remember the number of landmarks they pass as they travel between a food source and their hive. The Desert Ant counts steps to track how far it has traveled from its nest on foraging trips. Counting helps River Frogs to find a mate by the pulses in their croak. They need to count the number of pulses in their croak and can do so in phrases of up to 10 notes long. It is believed that they measure the volume and length of the other croak.
Small fish benefit from living in schools, and the more numerous the group, the statistically better a fish’s odds of escaping predation.
Gray Wolves require specific numbers in their packs to hunt, depending on what they are pursuing. When it’s elk they’re after, six to eight wolves are needed to be successful; for bison, nine to thirteen are necessary. And their prey use numbers as well. The elk will split into smaller herds to avoid encountering wolves or combine into larger herds to limit their chances of being hunted. This strategy has become popularly referred to as “safety in numbers.”
Two number systems
When we think of counting, we think of "one, two, three." But that of course relies on numerical language, which young humans and animals do not possess. Instead, they use two distinct number systems.
Human infants are already familiar with numbers at the age of ten months. However, their numerical abilities are limited: they can only detect changes between one and three, such as removing one apple from a group of three apples. This skill is shared by many animals with significantly smaller brains. For large numbers, they use another internal number system specialized for approximating large numbers imprecisely—the so-called approximate number system.
Fish, birds, bees, dolphins, elephants, and primates have all been found to possess an approximate number system when they quickly pick the most bountiful food source.
Scientists have found that animals across the spectrum have a keen sense of quantity and are able to distinguish not just bigger from smaller or more from less, but two from four, four from ten, and even forty from sixty.
While we humans and animals can both extract numerical information from our environment, it is still the language that sets us apart, precisely because it helps us not only pick the bush with the most berries but also perform intricate calculations that support civilization as a whole.