Reacción a "Gibraltar macaques might ingest soil to mitigate digestive discomfort caused by food provided by tourists"

The study by Frater and colleagues provides a novel account of geophagy (soil ingestion) in the Barbary macaques of Gibraltar, a population living in a context of intense human interaction. Based on systematic observations and spatial and dietary analyses, the authors show that this behaviour is relatively common and is associated with the consumption of food provided by tourists. The work stands out for its integrative approach and for illustrating how certain behaviours can emerge and persist in highly anthropogenic environments, offering a clear example of behavioural flexibility in primates.

However, the conclusions should be interpreted with caution. All the evidence comes from a single population that does not inhabit a natural setting for the species, but rather an artificial environment with regular food provisioning and diets far removed from the original ecological conditions. Moreover, although an association is observed between geophagy and the consumption of human-derived food, the actual quantities ingested by the macaques and their physiological impact are not clearly quantified, making it difficult to conclusively test the proposed functional hypotheses. In addition, the different hypotheses are assessed using variable sample sizes and observational methodologies that are not always equivalent, complicating the interpretation of whether the observed patterns consistently support one explanation over another. Finally, comparisons with other populations bring together highly heterogeneous contexts (ranging from wild populations to zoo settings) without truly comparable data. Overall, the study provides valuable information at a local scale, but it also highlights the need for caution when extrapolating these findings to the natural behaviour of the Barbary macaque more broadly.