Researchers have found that social rank affects how carefully monkeys eat their food. Footage shows dominant and low-ranked macaques eating quickly, often ingesting sand along with their food. Middle-ranked monkeys were more meticulous, washing their food in the sea to remove sand. A study by researchers at Dartmouth College in New Hampshire highlights how social rank influences eating habits among long-tailed macaques. Published in the journal eLife, the research was conducted on Thailand's Koram Island in Prachuap Khiri Khan province and observed distinct behaviours based on social status. The study indicated the eating habits may be linked to long-term health considerations such as preserving tooth enamel and maximizing reproductive success. Nathaniel Dominy, the study's corresponding author and Charles Hansen, Professor of Anthropology at Dartmouth, highlighted the significance of these findings in understanding how animals navigate trade-offs between immediate needs and long-term benefits. The study supports the disposable soma hypothesis, suggesting that animals sometimes prioritize immediate survival and reproduction over longevity. Amanda Tan, co-author and assistant professor of anthropology at Durham University, pointed out the role of social structure in shaping these manners. She also highlighted the rarity of food-washing among primates and its cultural transmission, similar to the conduct seen in Japanese macaques on Kojima Island. The study sheds light on the complexity of animal behaviour and the adaptive strategies within hierarchical groups, providing insights into evolutionary pressures and social behaviour.