 mice communicate through chemical signals which can be detected by their urine. Protein and metabolite levels in urine were compared across different environments, sexes and subspecies of mice. The results showed that environment had a strong effect on protein and metabolite levels while males had more sex-specific proteins than females. Machine learning was used to identify combinations of metabolites and proteins that could be used to predict certain characteristics of the mice. This study provides insight into how chemical signals are used for communication in mice, as well as how environmental factors affect the composition of these signals. This article was authored by Romana Stopkova, Teresa Machková, Alicia Doudakova, and others.