In Japan, deer will usually walk onto train tracks to lick the railings for iron particles. This has proven fatal for deer that get so engrossed in licking the tracks that they do not realize a train is coming. To reduce collisions, train companies have employed some unorthodox tactics.

They have smeared lion feces on the tracks in areas where deer are often spotted. That plan failed because rain washed the feces away. A second plan involved the the use of ultrasonic waves which only switched on when a train was nearby.

The Railway Technical Research Institute (RTRI) came up with another ingenuous idea. They simply installed a speaker to play deer and dog sounds on a train. The speaker makes the snort sounds of a deer for three seconds whenever a deer is spotted. This sound is used to get the deer’s attention.

The snort is quickly followed by 20 seconds of a barking dog that will usually cause the deer to scamper for safety. During tests, the number of deer that remained near the tracks when the train approached was halved. The institute also plans to install permanent speakers of barking dogs in areas where deer are often spotted.