What Is It Like to Be a Bat?

What is it like to be a bat?

I frequently thought about this question while I studied bat echolocation while pursuing my Ph.D. at Brown University. "What Is It Like to Be a Bat?" is the name of a philosophy paper written by Thomas Nagel in 1974. The paper isn't really about the sensory world of bats; it's a critique of reductionist theories of the mind. Nagel argues that consciousness has a subjective aspect, and that understanding other mental states is difficult or impossible for those not able to experience those mental states.

Nagel chose bats for a reason. They are mammals, and relatively closely related to humans. We have a great deal in common with bats: We are warm-blooded, care for our young, and have similar basic anatomy. But "anyone who has spent some time in an enclosed space with an excited bat knows what it is to encounter a fundamentally alien form of life," Nagel writes. He goes on to say that bats experience a range of activity and possess a sensory apparatus so different than ours that imagining what their experiences are like is an exceptionally challenging rhetorical question.

This philosophical question stayed in the back of my mind. When applying for grants, I would say that studying bat echolocation could help the Navy design better sonar systems, or help future researchers better understand how sounds are turned into neural signals in the brain. But what interested me were the bats themselves. What was it like to be a bat? What is it like to perform aerial acrobatics, live most of your life in complete darkness, and acquire nearly all of your information about the world from echoes bouncing off objects and back to your ears?

Neuroethology

Although my degree is in psychology, my research and my interests fall into the field of neuroethology, a multidisciplinary field made up of neurobiology (the study of the nervous system) and ethology (the study of natural behavior). Neuroethologists seek to understand how the brain translates stimuli into natural behaviors.

The emphasis on natural behavior, sometimes referred to as instinctive or innate behavior, sets neuroethology apart from other branches of neuroscience. You can think of natural behavior as those behaviors developed over the course of a species' evolution, like navigation, locomotion, predator defense, and mating. Studying naturally occurring behavior often means observing animals on their own turf. Unlike behaviorism, in which animals' reactions to artificial stimuli in a laboratory are studied, neuroethological studies often begin with the analysis and categorization of an animal's behaviors in the field. If the experimenter chooses to perform more controlled experiments in a laboratory, he or she makes an effort to mimic the natural context as closely as possible.

Another characteristic delineating neuroethology from other fields is the wide range of animal subjects. It's not just mice and fruit flies. Neuroethologists often choose to study animals that are specialists in a particular type of behavior (for example, bat echolocation or moth pheromone signaling). The neuroethological approach arises from the idea that animals' nervous systems have evolved to solve problems relevant to those animals in their environmental niche. Therefore, different nervous systems can be best understood in the context of the problems they have evolved to address.

On this blog, I want to share the sense of wonder and excitement I still feel when I read about an animal's behavior or abilities that I didn't know about. Some animals have such foreign ways of interacting with their environments: Honeybees see ultraviolet light, dogs can smell disease on human breath, sea lions can track fish in unlit waters by detecting turbulence trails with their whiskers. What is it like to sense the world this way?