For instance, rabies evolves slower while bats are hibernating. This means it also varies by location, since bats in the tropics don't hibernate.
Rabies viruses in tropical and sub-tropical bat species evolved nearly four times faster than those in bats in temperate regions.
"Species that are widely distributed can have different behaviors in different geographical areas," study researcher Daniel Streicker, of the University of Georgia, said in a statement. "Bats in the tropics are active year-round, so more rabies virus transmission events occur per year. Viruses in hibernating bats, on the other hand, might lose up to six months' worth of opportunities for transmission."
Understanding the relationship between host ecology and viral evolution rates could reveal details about other viruses, such as influenza, that occur across regions, infect multiple host species or whose transmission dynamics are impacted by humans.