"For as the eyes of bats are to the blaze of day, so is the reason in our soul to the things which are by nature most evident of all.” – Aristotle, Metaphysics

It is from this astute analogy written over 2,000 years ago that we still judge the erratic aeronautics of bats as a clear indication they are blind, hence, “blind as a bat!” Ironically Aristotle was clearly commenting on bats’ kinetic perambulations in daylight, even though bats generally venture out at twilight…

To shed a bright light on the myth, of the nearly 1,500 species of bats, accounting for roughly 20% of all mammal species on earth!, none of them are blind. All bats have functional eyes and the ability to see and spook considering they drink blood!

In fact, of the 1,500 bat species, three actually do feed exclusively on blood, a diet known as hematophagy or sanguivory: the common vampire bat, hairy-legged vampire bat, and white-winged vampire bat. Lucky for us here in Vermont, no vampire bats venture further north of Mexico. Vermont’s nine species of bats are all insectivores, and all can see!

Tricks and Treats – Cones and Rods

The human retina contains both rods responsible for low-light and black-and-white vision, and cones concerned with color and fine detail. Despite the tenor of Aristotle’s observations, bats are nocturnal animals like cats, opossums, and owls, and as such, have far more rods than cones in their retina making them highly adapted to seeing at night.

Humans are also adapted to seeing in low or dim light, though not as highly specialized as bats, owls, or ghosts, which apparitions apparently can see anything at any time of day or night! Human retinas contain approximately 120 million rod cells, which help us see in dim light after a period of adjustment.

While the human retina by contrast contains only 6-7 million cones, the photoreceptor cells specialized to see light, these cells do all the heavy lifting making humans especially adept for photopic vision, or daylight vision, thus when something goes bump in the night, or a bat flits by only a few feet away, our imperfect night vision might make us a little jumpy…

When it comes to TRICKS, bats definitely have the edge with echolocation and “heat vision”! Bats primarily navigate using echolocation, a process by which the bat emits a high frequency sound and listens for the echoes that bounce back off surrounding objects. With this information, the bat creates a map of its surroundings and can navigate with incredible agility.

Some bats can even navigate using heat vision. While not technically a visual process, bats can have special thermal receptors in their noses that can sense heat and can use this sense to seek out prey.

“I vant to suck your blood!”

Spiders have 8 eyes, ghosts can appear and disappear at will, bats can see at night much better than you, as can werewolves and black cats. It turns out, humans are at a grave disadvantage at cavorting at night, tempted to wander blindly seeking candy.

You might say that people, despite their costumes, are not at all literally but quite functionally blind!, if not so much as bats…