This study examines the diversity and evolution of chemoreceptor genes in vertebrates, focusing on six families of G protein-coupled receptors: *OR*, *TAAR*, *VIR*, *V2R*, *T1R*, and *T2R*. By analyzing 1,527 vertebrate genomes, the researchers found significant variations in the number and composition of chemoreceptor genes across different vertebrate groups. Amphibians, followed by mammals, have the largest chemoreceptor repertoires. The study also reveals that chemoreceptor gene families are co-evolving and highly dynamic, with lineage-specific expansions and losses. For example, *OR* genes are expanded in tetrapods, *TAAR* and *T1R* in teleosts, *VIR* in mammals, and *V2R* and *T2R* in amphibians. The number of *OR* genes correlates with habitat in mammals and birds, and with migratory behavior in birds, while the taste receptor repertoire correlates with diet in mammals and with aquatic environments in fish. The transition to a marine lifestyle has led to a reduction in chemoreceptor genes in marine tetrapods, and the loss of *TIR* genes in marine mammals is associated with dietary adaptations rather than high ocean sodium concentrations. The study provides insights into the ecological and morphological correlates of chemoreceptor evolution and highlights the importance of considering all six chemoreceptor families together.This study examines the diversity and evolution of chemoreceptor genes in vertebrates, focusing on six families of G protein-coupled receptors: *OR*, *TAAR*, *VIR*, *V2R*, *T1R*, and *T2R*. By analyzing 1,527 vertebrate genomes, the researchers found significant variations in the number and composition of chemoreceptor genes across different vertebrate groups. Amphibians, followed by mammals, have the largest chemoreceptor repertoires. The study also reveals that chemoreceptor gene families are co-evolving and highly dynamic, with lineage-specific expansions and losses. For example, *OR* genes are expanded in tetrapods, *TAAR* and *T1R* in teleosts, *VIR* in mammals, and *V2R* and *T2R* in amphibians. The number of *OR* genes correlates with habitat in mammals and birds, and with migratory behavior in birds, while the taste receptor repertoire correlates with diet in mammals and with aquatic environments in fish. The transition to a marine lifestyle has led to a reduction in chemoreceptor genes in marine tetrapods, and the loss of *TIR* genes in marine mammals is associated with dietary adaptations rather than high ocean sodium concentrations. The study provides insights into the ecological and morphological correlates of chemoreceptor evolution and highlights the importance of considering all six chemoreceptor families together.