In the eyes of other predators, earthworms are obviously an easy, low-defense meal, but you may not know how delicate the senses of earthworms are.
Although there is no hard grip and outer shell for protection, earthworms can travel in the soil for 600 million years and naturally they will not be a fuel-efficient lamp.
In addition to having an amazing reproduction speed ( see the data chart ), below we will explain how earthworms use a variety of senses and characteristics to help them escape from death’s door.
Where are the eyes/ears of the earthworm?
Earthworms are afraid of light and have no eyes. Because they grow in dark and humid soil, the eyes do not play a role for worms, so they gradually degenerate.
However, other sensory organs of earthworms are very sensitive, such as the earthworm’s skin with light-sensitive cells.
If you have raised earthworms, you know that after you grab them out of the soil and into sunlight, they’ll try and go right back into the soil within a few seconds.
Because of this, many farmers still use the artificial light method in the video below to separate earthworms from their eggs or castings (feces).
The experiment used a relatively large species of earthworms that move slowly. You can see that only the tail is irradiated by the flashlight and there will be soil drilling.
Here I have shared a few methods for separating earthworms, earthworm eggs, and worm feces.
Similarly, earthworms have no ears, so they can’t hear sounds.
However, they can sense sound produced by the vibration in their environment.
Whether it is walking, talking, or digging, there will be vibrations, and the earthworms will perceive it and escape in advance.
The earthworm’s body also has fine bristles that are barely visible.
These bristles are mainly to assist movement and to increase friction for travel on smooth surfaces.
But they can also help earthworms to better perceive the subtle vibrations around the soil.
To see how they use vibrations to escape, let’s use the example of moles.
Moles love to burrow and are also the number one natural predator of earthworms.
Vibrations occur when the mole is digging a hole into the soil, so the earthworm will immediately begin to make an escape or even attempt to get out of the earth before it becomes lunch.
In some countries, a type of vibration called worm grunting, is used by people to catch earthworms in the wild.
You can see worm grunting in action here.
A clever example of an earthworm predator using worms sensitivity to vibrations against themselves, is the herring gull.
A European herring gull, likes to use its feet to stomp on the ground constantly to produce vibrations, forcing earthworms to crawl out of the soil, only for the worm to become lunch for the clever bird.
Earthworms have a high degree of tactile, chemical and thermal sensitivity
Let’s get a bit more “sciencey”.
The earthworm body is covered with what is known as epidermal sensor cells, epidermal receptors, and each cell contains thousands of hair-like sensors that transmit messages to nerve fibres.
This means the earthworm has a high degree of perception to stimuli in its surroundings such as perception to touch, chemicals, and temperature changes.
Then there is another sensory cell located in the mouth called the “buccal” receptor.
These cells also allow earthworms to have a developed sense of taste and smell.
Finally, the photoreceptor cells that detect light are mostly located on the dorsal surface (the top) of the worm, and they get fewer under the abdomen and the closer you get to the tail.
Do you ever wonder, do earthworms have mouths? And can it eat bits of food like banana pieces? See our article above, we discuss the mouth of worms and how they eat.