In a thunderstorm you can watch the rain pelting the neighbors’ rooftops, while you sniff the damp dirt, hear the crackling thunder, taste the moist air, and revel in the water running down your face. A simple rain shower can engage all five senses. With each sense we can experience the wonderful world Hashem has made, We rely on our senses to tell us accurately about our surroundings. However, our five senses cannot detect everything. The world is full of information beyond our reach, but many animals have “sixth senses”—super senses that enable them to experience other dimensions of our world. These bonus senses help these creatures survive and thrive in their habitats.

One special sense is called mechanoreception. This sense allows web-spinning spiders to perceive minute pressure on their exoskeleton. Spiders have specialized organs called slit sensilla. These organs are small grooves at the spider’s joints, which change shape under stress. As the spider sits on its web, the slightest movement on the strand causes a slit to change shape, and mechanoreceptors in the slit detect the change.

The slit sensillum is so precise that the spider can determine the creature’s size and weight, or establish if the strain was just a passing breeze. The slit sensillum and other special senses are possibly as important for survival as the spider’s own eyes.