Research led by Kyoto University has sought to ‘lift the veil’ on disease avoidance strategies in multiple animal species, including humans

Life for all animals, including humans, would be simpler if diseases had a sign saying ‘Beware!’ with flashing lights and blaring alarms.

Instead, we humans have developed an emotional reaction called ‘disgust’. Do other animals share similar protective mechanisms?

While fear and predator avoidance have captured much attention in the field of animal behaviour, in comparison, little has been published regarding avoidance of disease.

An international team of scientists has now set up a framework to test disgust and its associated disease avoidance behaviours across various animal species, social systems, and habitats.

Lead author Cécile Sarabian, a former JSPS postdoctoral fellow at Kyoto University, said: “Over 30 species have been reported to exhibit disease avoidance strategies in the wild.

“We provide predictions for seven others that were previously overlooked and that could serve as new model species.”



Disease risk


With these predictions, the team accounts for models of specific ecological niches, sensory environments and social systems for a number of species including the native common octopus and the invasive red-eared slider, which are both relevant to Japan.

Co-author Andrew MacIntosh, associate professor at Kyoto University Wildlife Research Center, said: “The various costs and benefits involved in experiencing disgust and avoiding illness depend on the social system and ecology of the species.”

Disgust can be triggered by sensory cues associated with disease risk, such as the sight of diarrhoea, which releases a set of behavioural or physiological responses that help animals avoid parasites, pathogens, and toxins.

The levels of disgust behaviour vary also from species to species depending on their social systems and ecological niches.

Since solitary species have relatively fewer social interactions and resulting disease transmission, they are less adapted than group-living species in recognising and evading such life-threatening risks.

MacIntosh added: “Some species living in colonies, such as rabbits and penguins, go further in tolerating diseased mates since a community immunity strategy ensures the colony’s survival.”

The implications to human health are significant since expected disgust-driven behaviours can be applied to the study of the Covid-19 pandemic.

For example, a model of coronavirus infections that considers social distancing flattens the curve predicting the number of positive cases, in contrast to the exponential curve for cases without social distancing.

Sarabian concluded: “Beyond fundamental research, it’s important to keep promoting the creation of a database that gathers disease-avoidance evidence in animals and its applications in relevant conservation and wildlife management strategies.”

Image: The Adélie penguin, one of the species studied. © Jason Auch (CC-BY 2.0)

Research Aether / Earth Uncovered