Giraffes possess a capacity for simple mental arithmetic, according to a new study that indicates these long-necked mammals can mentally combine quantities to determine which of two options offers more food. This cognitive ability is comparable to performing basic addition sums and suggests a potential foundation for more complex mathematical skills.
The researchers hypothesize that these advanced cognitive skills may have evolved as a survival mechanism in response to the demanding savanna environment, where giraffes live in dynamic social groups and their primary food source, acacia trees, is often scattered.
"If this information were available to the giraffes, we could not conclude that the subjects are performing mental operations, as they might base their choice solely on the perceptual information available after the manipulation," explained co-author Iker Loidi, a PhD student at the University of Barcelona. "The key is that the quantities were kept hidden from the giraffes after those initial few seconds, meaning they need to keep track of the numbers entirely in their heads."
Scientists conducted experiments with four adult giraffes at the Barcelona Zoo. In the study, published in the journal Scientific Reports, giraffes were presented with two yellow containers, each holding a specific number of carrots. After a brief period, the containers were closed, and the giraffes were then shown a green container with additional carrots. These carrots were then added to one of the original yellow boxes without revealing the updated quantity.
Alternatively, the green container was shown empty before carrots were removed from one of the yellow boxes and placed into it, demonstrating subtraction. The giraffes' task was to identify which container held the most carrots by mentally calculating the combined quantities.
Despite the stringent experimental conditions, two of the four giraffes consistently succeeded in identifying the container with the most carrots. This indicates that giraffes can remember observed quantities, update that information mentally when quantities change, and make decisions based on these calculations.
However, the giraffes did not perform as well on subtraction tests or sequential operations, such as moving food from one container to another. "These results are consistent with what we observe in humans: there are individual differences in numerical problem-solving and, in general, subtraction is more difficult than addition," noted Loidi. He added that subtraction engages brain areas associated with complex, controlled processing, unlike addition.
These findings contribute to a growing body of evidence suggesting that sophisticated cognitive and quantitative skills are not exclusive to primates. Previous research has shown numerical abilities in other species, including chimpanzees, African grey parrots, crows, pigeons, monkeys, certain fish, and even bees, which have demonstrated the ability to learn simple mathematical problems.
"This study builds upon a broader research program where we have previously demonstrated that giraffes possess an array of cognitive abilities, including object permanence, quantity discrimination, and the capacity to make statistical inferences," said co-author Dr Álvaro López Caicoya of the Research Institute for Farm Animal Biology. "Altogether, this contributes to the growing evidence that complex cognitive and quantitative skills are not exclusive to primates, but may emerge in other species in response to their own socio-ecological demands."