A reader wrote to us about a strange thing that happened to him. His message was quite detailed and full of relevant information, so we will include the entire message with a little bit of editing: “I just had the weirdest thing happen. I found a worm in the middle of the floor of my room. It was about 1-1/2 inches maybe when fully extended. It was brown with a pink tip on one end and and a yellow tip on the other end. As I picked it up and took it outside, it excreted a black goo from the yellow tip, almost like ink. This inky excretion occurred several times, at least 3 or 4. I’ve never seen anything like it, searched high and low for an answer online but couldn’t find one. Unfortunately I have no picture, I didn’t even think about it. I live in eastern Pennsylvania. Hope you can help!”
We aren’t sure what kind of worm our reader has discovered. We aren’t familiar with any brown worms that have one pink tip and one yellow tip, and without a photo we can’t make an identification. However, we have a hunch that the worm is a caterpillar, which is the larva of a moth or butterfly!
Certain species of caterpillars are known to excrete a dark liquid as a defense mechanism. The regurgitated liquid serves as a repellent to predators, and can even be poisonous. This act of excretion is very costly in terms of energy, so it is often used as a last resort. Assuming our reader found a caterpillar, it was probably desperate to defend itself when it started excreting its inky goo. We hope our reader returned the caterpillar safely back outside.
In summary, one of our readers discovered a worm that appeared to vomit up black goo when he picked it up. We think he might have discovered a caterpillar that was regurgitating liquid as a defense mechanism.