Blind Cave Fish Find Food

How is bat guano controlled in caves, and how do blind cave fish find food? Like all natural balances, there is a relationship between these two questions.

With vast numbers of bats in caves, over many years, their droppings could fill the caves if there were no natural ways to reduce the volume. Dr. Josh Gross at the University of Cincinnati has discovered that blind cave fish actually eat bat guano. It provides food for the fish, which would otherwise have nothing to eat.

What the fish get from the guano depends on what kind of bats live in the cave. Fruit bats will have some sugar in their guano, and bats that eat insects will have some protein in theirs. The next question is, how do the fish find the guano that will nourish them? The answer is that the fish have taste buds under their chin and on top of their heads.

The fish avoid destructive bacteria that might be in the guano because some of the taste buds can detect lactones in the bacteria that would taste bitter. These taste buds are called tuft cells, and in addition to harmful bacteria, they can detect dust mites and mold.

Everywhere we look in the natural world, even in the darkest caves, we see God’s design and handiwork, even in how blind cave fish find food. Romans 1:20, “We can know there is a God through the things He has made,” has special meaning when we see examples like this.

— John N. Clayton © 2024
References: “A Matter of Taste” in Scientific American for November 2024, page 16 and Nature Communications Biology