Are elephants afraid of mice? Well, maybe. There isn’t much evidence, unless you like sample sizes of 1 individual. However, elephants are definitely afraid of ants, and that is a much more interesting ecological story.
Last week, I posted an introduction to the symbiosis between ants and plants. One of the services provided by ants is protection from herbivores. Those herbivores may be insects, like caterpillars and grasshoppers, but they may also be megafauna, like elephants.
Elephants love munching on Acacia trees, but some Acacia species are protected by ants. With the ants removed, elephants will gladly eat species that typically have ants. But when the ants are present, the elephants avoid defended trees (Goheen and Palmer 2010). This decision to avoid getting viciously stung by hordes of ants may have far-reaching consequences in savanna ecosystems: tree community composition is affected, because defended tree species are more likely to survive in areas with many elephants (Goheen and Palmer 2010). Tiny symbionts can play big roles in ecological communities!
Goheen JR, Palmer TM (2010) Defensive plant-ants stabilize megaherbivore-driven landscape change in an African savanna. Curr Biol 20:1768–72.