14. Long-Tailed Macaques
Certain populations of long-tailed macaques have been observed using stones to crack open shellfish and nuts, demonstrating their ability to utilize tools for accessing food resources. Additionally, in Lopburi, Thailand, these macaques have been seen using human hair as dental floss, a behavior that appears to be a learned cultural practice within specific groups. (pubmed.ncbi.nlm.nih.gov) These behaviors vary between groups, providing insights into culture and learning among primates. (ox.ac.uk)