Functional insights into the effect of feralisation on the gut microbiota of cats worldwide

Feralisation, the process by which domesticated organisms revert to a wild state, is a widespread phenomenon across various species. Successfully adapting to a new environment with different access to food, shelter, and other resources requires rapid physiological and behavioural changes, which could potentially be facilitated by gut microbiota plasticity. To investigate whether alterations in gut microbiota support this transition to a feral lifestyle, we analysed the gut microbiomes of domestic and feral cats from six geographically diverse locations using genome-resolved metagenomics. By reconstructing 229 draft genomes from 92 cats, we identified a typical carnivore microbiome structure, with notable diversity and taxonomic differences across regions. While overall diversity metrics did not differ significantly between domestic and feral cats, hierarchical modelling of species communities, accounting for geographic and sex covariates, revealed distinct taxonomic and functional profiles between the two groups. While taxonomic enrichment was balanced, microbial functional capacities were significantly enriched in feral cats. These functional enhancements, particularly in amino acid and lipid degradation, correspond to feral cats' dietary reliance on crude protein and fat. Additionally, functional differences were consistent with behavioural contrasts, such as the more aggressive and elusive behaviour measured in feral cats compared to the docile behaviour of domestic cats. Finally, the observed enrichment in short-chain fatty acid, neurotransmitter, and vitamin B12 production in feral cats aligns with improved cognitive function and potentially contributes to their heightened aggression and elusiveness. Our findings suggest that microbiome shifts may play a significant role in the development of physiological and behavioural traits advantageous for a feral lifestyle, supporting the adaptive success of feral cats in the wild.