Why are tarantulas almost blind?

Tarantulas are almost blind due to their reliance on other senses, particularly touch and smell, to navigate their environment. Their eyes are limited in number and primarily detect light and movement rather than detailed images. This adaptation suits their lifestyle as nocturnal hunters, where sensitivity to vibrations and chemical cues in the air is more beneficial for locating prey and avoiding predators. As a result, their visual acuity is not a priority for survival.