More, less or the same amount? Not only humans, but also many animals can record numerical differences. A German neurobiologist is now summarizing the current state of research on this interesting topic. It illustrates how amazingly widespread a numerical quantity understanding is in the animal kingdom, what it can serve and what is known about mechanisms of perception. He concludes that more targeted research is needed to better understand the importance of this particular animal ability.
In humans, the innate sense of quantitative relationships forms the basis for our higher mathematical abilities. For a long time this was considered a unique selling point of human intelligence. But it is now clear that many animal species can at least roughly distinguish between different sets of objects, as Andreas Nieder from the University of Tübingen explains in his publication. He has already contributed to the knowledge in this area – now he has dedicated a so-called review to the topic, which clarifies the previous knowledge. For this purpose, he also collected relevant information from studies that only provide conclusions about numerical skills in animals.
Widespread skill
“Interestingly, it is becoming apparent that there are numerical skills in animals of almost all lineages,” says Nieder. “Obviously, different groups created this characteristic independently of one another. This strongly suggests that it has great adaptive value: In many cases, the ability to record differences in numbers must have conveyed a strong survival and reproductive advantage, ”said the scientist.
As he reports, many numerically gifted animal species cannot record exact numbers, but at least they understand the principle of “more or less”. This ability can have very different meanings for the respective animal species, as Nieder shows in his review: The quantity understanding can be helpful, among other things, when hunting, choosing a partner or orienting. In the end, numerical competence can play an important role in how sensibly animals make decisions, Nieder writes.
It seems comparatively unsurprising that animals such as monkeys, dogs or raven birds are considered to be particularly highly developed. However, studies on insects illustrate how widespread the ability is in the animal kingdom. Nieder emphasizes research on bees in this context. For example, you can remember the number of landmarks they flew past in search of food. This can help them find their way back to the beehive. Nieder emphasizes: “The last common ancestor of bees and us primates lived about 600 million years ago. However, these insects have developed a numerical competence that is comparable to that of vertebrates in many ways. ”
Subtle references to numerical skills
Sometimes studies seem to have to read between the lines, as it were, in order to recognize clues about the numerical abilities of animals, as the review shows. They are reflected, for example, in the croaking of some species of frog. These are “advertising” calls from males to attract females. As Nieder reports, studies have shown that the females of some species pay attention to the complexity of the calls. Specifically: the male, who can produce a particularly large number of repetitions of a certain sound element, has increased chances with the women. This in turn suggests that these amphibians can distinguish amounts.
Another interesting example that Nieder emphasizes is found in wolves. They obviously have a feel for how many pack members are needed to hunt for specific prey. It takes only six to eight wolves to kill moose, while hunting bison requires a pack of nine to thirteen wolves. The prey apparently also have a feeling for numerical sizes – in this case, to protect themselves from the predators: if elk are rarely confronted with wolves, they form only small groups. The greater the threat, the more animals they value in their communities. “So they obviously roughly record the number of individuals in their herds in order to adapt to the situation,” says Nieder.
A research field with potential
Despite many examples of numerical competence in animals, however, comparatively few researchers have specifically addressed this topic, says the biologist. “Many of these behavioral findings in the wild have mostly been collected as by-products or accidental results of other research questions,” says Nieder. According to him, targeted research is now needed to better understand the role numerical competence plays in the life of different animal species and how this ability has shaped their developmental history.
He will now devote himself to researching another interesting aspect of this topic: What is the neural basis for numerical understanding in animals? He has already done pioneering work in this area: he and his colleagues were able to show where the “data center” is in the brain of crows when the birds differentiate between point sets. The Tübingen scientists now want to build on this work. They plan to discover more precisely how animals’ brains and nerve cells process numbers.
Through his review, Nieder hopes to attract more attention to the exciting research topic: “Perhaps I can encourage behavioral researchers to specifically research numerical competence in nature and thus also open up new fields of research,” said the scientist.
Source: Cell Press, technical article: Trends in Ecology & Evolution, doi: 10.1016 / j.tree.2020.02.009