Why Do Wet Dogs Shake?

When a dog shakes off water from its fur, this action is not random or meant to intentionally wet those nearby. Many furry mammals exhibit this instinctive reflex, including rodents, cats, squirrels, lions, tigers, and bears. Researchers at Harvard University in the United States have now identified the neural circuitry that triggers the typical "wet dog" shaking behavior in mice, involving a special type of tactile sensor called "C-Low Threshold Mechanoreceptor (C-LTMR)" and neurons that connect the spinal cord to the brain. These findings were published in the latest issue of the journal Science.

In humans, tactile sensors are associated with pleasurable sensations, such as gentle hugs or soft touches. However, in mice and other animals, they serve a protective role: alerting the skin to the presence of foreign objects, whether water, dust, or parasites. Researchers state that when these stimuli cause hair bending on the skin, it activates C-LTMR, "making the skin's sensitivity extend beyond the surface".

Researchers also studied how signals from C-LTMR coordinate the shaking behavior of a wet dog through the nervous system. They traced a group of neurons in the spinal cord that connect to the periaqueductal gray region in the brain, which is involved in processing pain, temperature, and touch.

Neuroscientists suggest that the shaking behavior of a wet dog is a highly coordinated motor response, providing a solid starting point for exploring how the brain commands and controls movements.