Mice are supposed to strike terror into the hearts of elephants - at least if Disney cartoons are to be believed.
But Dumbo's tormentors are actually even smaller, scientists claim.
Researchers have discovered that ants are the bane of elephants' lives, with the giants of the African savannah steering clear of trees infested with them just in case they crawl up their sensitive trunks.
The experts who made the discovery believe ants act as 'bodyguards' for some plants to keep trampling elephants at bay.
Dr Todd Palmer of the Mpala Research Centre in Kenya and the University of Florida said: 'It really is a David and Goliath type of story, where these little ants are up against these huge herbivores, protecting trees and having a major impact on the properties of the ecosystems in which they live.
'Swarming groups of ants that weigh about 5mg each can and do protect trees from animals that are about a billion times more massive,' Dr Palmer said.
'It's yet another example of how the little things run the world.'
The idea that elephants fear mice has long been a staple of cartoons, and features in the 1941 Disney classic Dumbo.
However, animal behaviourists say there is no evidence of rodent-phobia among any mammal.
The discovery that elephants dislike ants came when Dr Palmer and colleague Dr Jacob Goheen noticed elephants avoiding a species of acacia tree in the Kenyan plains.
The trees are found across the African savanna and are normally devoured and trampled by hungry elephants. However, they stayed away from acacia drepanolobium trees if they were home to guardian ants.
'The elephants avoided those trees like a kid avoids broccoli,' Dr Palmer said.
'It seems that elephants simply do not like ants swarming up the insides of their trunks, and I can't say I blame them.
'An elephant's trunk is a truly remarkable organ, but also appears to be their Achilles heel when it comes to squaring off with an angry ant colony.'
The scientists believe that adding ant colonies to vulnerable plants in Africa could prevent deforestation and protect crops.
Elephants have such large appetites they can soon convert woody areas into open grassland.
'A big issue in east Africa is elephants damaging crops, which is one reason elephants have been harassed and sometimes killed,' he added.