What if we could understand what animals are really saying? At UW, scientists are breaking barriers in animal communication, uncovering the hidden languages of bats, rats and mice.
Dr. Ellen Covey, a Neural Systems and Behavior professor at UW is a leading neuroethologist specializing in bat echolocation.
When a bat sends an outgoing call, such as a tongue click, it uses the returning echo to gather detailed information about its surroundings, she explained. Echolocation allows the bat to determine the location, movement and characteristics of objects in its environment. According to Covey, the calls are emitted in such a way that directs the sound in a narrow beam, ensuring it is only received by the bat that sent it.
One of the things scientists study, Covey said, is the development of echolocation calls in baby bats.
“When a baby bat is born, it first emits what’s called an isolation call,” Covey said. “It’s like a ‘Come get me!’”
The mothers, she explained, can identify the calls of their own babies because there are subtle differences the bats can pick up on.
“And then they start doing what’s equivalent to babbling in human babies,” Covey said.
These random noises gradually evolve into the communication and echolocation calls used by their peers. Each bat species has its own distinct set of calls. The young bats observe and learn these calls from those around them, eventually adopting them as well. Bats are also able to easily distinguish between each other’s communication sounds and echolocation calls.
“It would be like being able to tell the difference between somebody speaking to you and somebody singing,” Covey said.
Besides vocal communication, bats also communicate via smell, touch, and sight. With numerous scent glands located across various parts of their bodies, they often rub against each other as a form of communication. Bats engage in tactile interactions such as grooming, touching wings, and licking to convey information. Covey also suggested that bats may communicate visually to some degree, though she is still uncertain about the extent of its role in their overall communication.
Echolocation research has contributed to modern advancements in artificial systems for range-finding. Robotics, Navy research, and autonomous vehicles have all drawn inspiration from bat echolocation. This strategy of clicking or making some kind of noise and listening to the echoes that come back has even been adopted by blind individuals, Covey said.
As a self-proclaimed opportunistic activist for the bats, Covey urges readers to protect the bats, their habitats and their food source.
“And by the way, bats are not blind . . . You would be blind too if you were in a cave with no light,” Covey said.
Another professor making waves in understanding animal communication is Research Assistant Professor and Acting Instructor at the Neumaier Lab, Dr. Kevin Coffey.
Under the Neumaier Lab, Coffey, then a postdoctoral fellow, and alumni Laboratory Technician Ruby Marx developed DeepSqueak, an AI system designed to analyze mouse and rat vocalizations. The scientists published their research on this technology in 2019.
The program can detect, classify, and analyze ultrasonic vocalizations (USVs) in rats and mice.
“DeepSqueak uses machine vision… the same tech that lets a self-driving car identify a person vs. a stop sign, to detect vocalizations in audio files,” Coffey said.
These audio files are converted into images also known as a spectogram. USVs emitted by rats and mice are above the human hearing range so they need to be converted to images to be analyzed by humans, Coffey explained. While the program was originally designed for rat and mouse calls, it has now been trained in different labs to identify dolphins, whales, birds, lemurs, zebras, and monkey calls.
This technology offers a unique perspective into the emotional states of rats and mice. As highly social animals, these rodents use vocalizations as part of their social interactions, Coffey said. While they have distinct alarm calls for survival, they also have calls used during play that help determine social hierarchy, as well as for activities like courtship or maternal pup retrieval.
“Rats in particular enjoy rough and tumble play and communicate continuously during [these interactions],” Coffey said. “I think that it’s highly analogous to fun.”
DeepSqueak aids in identifying which vocalizations are associated with emotions like happiness, aggression, anxiety, and more. Yet, Coffey noted that “relating those calls back to behavior to provide semantic meaning is still an ongoing process.”
With a primary focus on the study of chronic fentanyl use, Coffey developed DeepSqueak in part to better understand opioid withdrawal in humans.
“Say we believe manipulating a particular brain circuit will reduce opioid withdrawal symptoms, with USVs we can let the rodents directly express how they feel,” Coffey said. “This is much more direct than trying to interpret emotional state from behavior, and will make it easier to translate our work to humans in the future.”
Other than USVs, rodents use body language, scent cues, physical interaction and audible vocalizations to communicate.
“They are also very capable of communicating with humans,” Coffey said. “I often get asked if tools like DeepSqueak will help us communicate with animals, but the reality is we do this all the time. You know when your dog [or] cat is happy, hungry, has to go out because they are always communicating with you.”
Classifying USVs simply provides additional understanding of rodent communication, he clarified.
Technology is advancing to understand animal communication more than ever, but Coffey cautions we might not be able to talk to rats quite yet about inflation.
Reach contributing writer Marina Blatt at [email protected]. X:@Mblatt02
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