Social Distancing in Animal Populations


Charlie Desnoyers, Staff Writer

In a time where social distancing is expected during this pandemic, humans feel as if it is unnatural or forced compared to our usual daily routines. We are expected to separate ourselves from other people, infected or not, and infected individuals are to be distanced from everyone. As unnatural as this feels, in nature it is almost the normal as we see many animal populations distance themselves from infected animals. Whether it be detecting diseased animals through chemicals in urine to separating themselves from infected individuals, animals are able to make the decision to change their interactions based on a disease in their community. 

Ecologists call this behavior of social distancing in nature “behavioral immunity”. Psychologist Mark Schaller coined the term when talking about groups of animals who adapted to recognize a disease within a population and use different tactics to get rid of said disease. This process came to be as animal and human ancestors came in contact with many different pathogens including parasites, diseases, viruses, etc. The thousands of years of contact with these pathogens came for many animal populations to develop a suite of psychological responses to an animal being infected. These responses include a wide variety of tactics which varied based on where the certain population lives. 

One major animal population we see take measures to end a disease within a population are social insects. These insects such as ants, bees, wasps, and termites have complex social and physical interactions which allow for a complex understanding of the other insects in their population, allowing them to know when one has a disease. In a study conducted by Nathalie Stroeymeyt, a lecturer at the University of Bristol’s School of Biological Sciences, found when a fungal disease was introduced into a garden ant population, the ants separated themselves from the infected ants. This proactive approach is efficient and substantially decreases the spread of the certain disease within the ant population. Another example of this proactive approach is in certain lobster populations. Lobsters are able to detect chemicals in other lobsters urine which can tell if they are infected or not. This then allows the lobsters to distance themselves from the infected lobster. While the detectable chemicals in urine are not a trait for all animals, the idea of quarantining sick animals and staying away from sick ones are still present.

These tactics we see are the best option compared to an immunological approach such as herd immunity or vaccination. Depending on the pathogen, an animal population may not be able to successfully do herd immunity due to its severity. If you are not familiar with the term, herd immunity is when a population gains immunity from a pathogen due to previous infection or vaccination. However in an animal population, vaccination is not a viable option, so a majority of the population has to be infected and recovered to be immune. This is a way to eradicate a disease from a population if the disease does not kill the population quickly. If the disease has a high mortality (death) rate, the infected individuals would not be able to recover quickly, meaning the desired effects of herd immunity could not be achieved. 

Would we be able to learn a thing or two from the animal populations we see naturally social distance and quarantine from sick individuals? That all depends on if people actually want to put in the effort to end this global epidemic. We need to wear masks, stay socially distant from other people, wash hands, and avoid close contacts with numerous people. If lobsters do it, we can too.