Sable Island Horses Share Survival-Linked Gut Microbes, With Social Ties 2-4 Times Stronger Than Genes
Updated
Updated · spacedaily.com · Aug 18
Sable Island Horses Share Survival-Linked Gut Microbes, With Social Ties 2-4 Times Stronger Than Genes
1 articles · Updated · spacedaily.com · Aug 18
Summary
2,394 fecal samples from 794 Sable Island horses showed gut microbiomes tied to survival were more similar among related animals, but social contact shaped those microbes even more strongly.
47% of variation in survival-linked microbiome traits and 38% in microbial gene families were explained by genetics, stable environment and social associations combined; direct social effects were 2-4 times larger than genetic effects.
The preprint argues this could let natural selection act on microbiomes because the traits both affect survival and are transmitted consistently through genes and social exposure, not because bacteria are hardwired in DNA.
A 2024 study by the same group linked lower methane-producing gut microbes to better winter survival, suggesting digestive efficiency can matter on the predator-free, food-limited island.
The authors say the finding is still correlational, unreviewed and based on one isolated horse population, leaving open whether the microbiome patterns persist as social relationships change over time.