Detection of underground activity by the red fox

The researchers hypothesize that the fox uses not only the sense of hearing, but also the Earth's magnetic field to locate its prey

By: Dafna Haim-Langford

These days, many small talk revolves around the question of how to locate those offensive and other tunnels that threaten our daily lives and the safety of citizens and soldiers in the southern settlements and in general. In this issue we have chosen to describe one of the fascinating mechanisms that enable the hunter of invisible prey.

The Israeli Iron Dome has proven, in the current round of violence, its great effectiveness in protecting the civilian population from missiles. The next challenge facing the security forces is to develop "Iron Dome" technology against the offensive tunnels that threaten the settlements near the borders.

The quality of the terrorist tunnels and their number constitute a significant challenge for the security forces, and we are sure that the best minds are already working and developing advanced systems for locating underground tunnels. As with any challenge, this topic, of underground detection, was developed over hundreds of millions of years of evolution and is an example of one of the mechanisms mentioned here.

Red fox is the largest and most common fox in the Northern Hemisphere and is considered the most common predator in the world. The red fox feeds on small rodents, unlike other mammals, it recognizes low-frequency sound very well. During its evolutionary development, the red fox developed a sense system that allows it to hunt even in extreme weather conditions. The sensory system of the red fox is mainly based on the sense of hearing. The fox's hearing ability allows it to hear when a bird moves to another branch at a distance of 600 steps, a crow flies at a distance of about half a kilometer and the movement of a mouse at a distance of about 100 meters. The fox is able to detect sounds in the range of 3,000-700 Hz. The most interesting thing is the ability of the red fox to locate, which allows it to hunt small rodents at a depth of a meter or more under the surface of the snow even without seeing them.

Scientists claim that the wonderful hunting ability of the fox is not based on the sense of hearing alone. From hundreds of observations, it has been found that the chances of success for a fox when it faces northeast are significantly higher than in any other direction, especially when its prey is under the surface of the snow. The researchers speculate that the fox uses not only the sense of hearing, but also the Earth's magnetic field to locate its prey. When a fox follows the sound of its unseen prey, it looks for the point where the angle from which the sound is coming corresponds to the gradient of the Earth's magnetic field. When the fox finds this point, it knows the exact distance from the prey and can accurately calculate the required jump length. If the researchers are right, the red fox is the first animal known to us to use the "magnetic sense" to hunt and to estimate distance. Many animals such as ants, birds, snakes and cows sense the magnetic field and use this sensing ability for navigation and positioning.

Can we use the "magnetic sense" in combination with echolocation to identify an underground occurrence such as digging a tunnel?

A wonderful video demonstrating how a red fox hunts rodents in the depths of the snow

Technion researchers have developed a way to locate tunnels using optical fibers