The usual but inexplicable behavior of dogs has finally been explained

Dogs and humans have lived together for thousands of years, and researchers have studied their behavior well. Every owner noticed that dogs shake after bathing, but why - biologists did not know. Scientists found the answer to this question.

A team from Harvard Medical School found out that a receptor in the skin of mammals - C-LTMR - is responsible for "wet shaking" in dogs. It is this receptor that causes not only dogs, but also cats, mice and other animals to tremble when drops of liquid fall on the back of the head.

According to one of the authors of the study, Dawei Zhang, all animals shake with the same frequency and according to a similar pattern: three back-and-forth movements at a time. Previously, scientists did not know exactly which receptors and nerves trigger this behavior, but now they have figured out this mechanism.

Genetically modified mice were used for experiments. In some mice, the receptors that recognize mechanical influences were turned off, in others - those responsible for temperature changes. Mice that don't sense temperature still shivered if water came on them. But those whose mechanoreceptors were blocked did not shake.

Further analysis revealed that three receptors that respond to light touch are responsible for this behavior. Using optogenetics – a method in which nerves are activated by light – the scientists stimulated these receptors without using liquid. Stimulation of the C-LTMR receptor was found to cause tremors in mice.

When the scientists created mice without the C-LTMR receptor, they shook 58% less than normal mice when exposed to water. Zhang explained that for a long time these receptors remained a mystery: for 80 years they were associated with the sensation of tickling, but the mechanisms of operation remained unknown. Humans have similar receptors, called C-mechanoreceptors, which elicit pleasant sensations from light touch.

The researchers believe that C-LTMRs transmit signals from the follicles of the animal's undercoat. This helps them detect small stimuli such as water droplets or parasites.