In addition to humans, some species of primates and birds have demonstrated, under experimental conditions, their ability to manipulate quantities in tasks that require combining or separating them, in a manner similar to addition or subtraction. Now, a study by the University of Barcelona, published in the journal
Scientific Reports, reveals that some giraffes are also capable of deciding which of two options contains more food after mentally combining two quantities, a process comparable to a simple addition. These results suggest that giraffes possess a cognitive foundation that could support more complex arithmetic skills.
This study was led by Iker Loidi and Jordi Galbany, from the Department of Clinical Psychology and Psychobiology at the Faculty of Psychology, and researchers from the UB Institute of Neurosciences (UBneuro). Researchers from the Barcelona Zoo also took part, as well as those from the Research Institute for Farm Animal Biology (FBN), Leipzig University and the Max Planck Institute for Evolutionary Anthropology in Germany.
The study also challenges the notion that complex cognitive abilities are unique to humans and other primates, and supports the hypothesis that certain sophisticated abilities may have evolved convergently across different animal lineages.
A carrot-based test to assess giraffes’ numerical abilities
Giraffes belong to the order Ungulata, a group of mammals characterized by having hooves, which includes species such as hippos, camels and deer. These animals have demonstrated strong abilities in numerical tasks, such as distinguishing between different quantities — identifying where there is more and where there is less — or performing simple statistical calculations to determine which of two options most frequently provides their preferred food.
As part of the study, the team designed a test involving four specimens from the Barcelona Zoo to see whether they were able to choose the container with the most food from two options, one of which had been changed during the process. “The change could involve adding food, as in addition; removing food, as in subtraction; or carrying out sequential operations, such as removing food from one option and adding it to the other,” explains Loidi.
Each animal was shown two different quantities of carrots in two yellow containers, which were then closed after a few seconds. They were then shown another green container, which held the amount of food that was added to one of the original containers. Once the addition was made, the animals could choose which container they preferred, without ever having seen the final result of the operation. In the subtraction task, the green container was initially empty and served to collect the items removed from the yellow containers.
The key factor is that the quantities were no longer visible to the animal after the initial presentation. “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,” notes the expert.
Finally, two of the four giraffes that took part in the study solved the quantity-addition tasks, suggesting that these animals “can remember quantities they have observed, mentally update that information following changes, and make optimal decisions based on it.”
However, none of the giraffes managed to solve the subtraction tasks or the sequential calculations. “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. Furthermore, subtraction activates areas of the brain specializing in complex, controlled processing that addition does not stimulate,” notes Loidi.
A broader look at the evolution of animal cognition
The demanding socio-ecological conditions faced by giraffes could explain the notable development of their numerical abilities. They live in communities that split into smaller groups and regroup according to environmental conditions, and their main food sources — particularly acacia trees — are scattered across the savanna, “which could encourage the need to estimate where, when and in what quantities these resources are available in order to optimize foraging decisions”, notes Loidi.
“These findings help challenge an overly anthropocentric view of cognition and highlight the importance of studying a wider diversity of groups and species in order to better understand the evolution of the animal mind,” concludes the researcher.