Friday, July 21, 2023

On breathing and pooping snails

This little snail was crossing my driveway, almost under my front tire. Not a safe place, little one! I put him in a bowl of lemon balm to take a few photos before I relocated him to the lawn, a good distance from my flower beds.

He didn't like the lemon balm.

Grove snail, Cepaea nemoralis

And quickly found his way out of the bowl, away from those lemony leaves.

On his way.


And onto my desk. Where he made a wild dash for freedom, pooping as he went.

Yes, that is snail poop.

I had never actually watched a land snail in the act of excreting before, and looking at this photo, it seemed to me that the poop was leaving through the pneumostome, the breathing pore, which is always on the right side, (in the slugs, too) near the edge of the shell. In the diagrams I found of snail anatomy, the anus is close to this hole, but farther inside the shell.

But no, I was not seeing things:
Snail poop is discharged from the anus, which is near to and connected to the lung and breathing hole. This implies that when a snail poops, it does so in its shell. The poop then falls through the breathing hole and out of the shell’s side, falling to the ground or whatever surface the snail is crawling on. (Garden Tips)
Snails are weird. but this, I had to confirm. And there's a page dedicated entirely to snail poop, where I found: 
The breathing hole supplies the lungs with air. The anus is also on this same side. So apart from its usage for respiratory purposes, the breathing hole also serves as an outlet for passing the snail poop out of the body. The bottom line is:
Snails have internal organs, including an anus that secretes digestive waste inside the shell, not outside. 
The poop, after release, passes through the breathing hole and comes out from the side of the central opening of the shell. (A-Z Animals)

There's always more. While I looked at diagrams and descriptions of snail anatomy, I found this:

The sense of sight of snails is useful but only detect changes in the intensity of light to recognize whether it is night or day; They can move their tentacles up or down to improve their ability to see. However, they are practically deaf since they have no ears nor ear canal. To compensate this absence of hearing they have an excellent associative thought which helps them remember the places where they were or where the objects of their surroundings are. (Snail World - Snail Anatomy)

I hope this guy remembers that my driveway is not a good place to be.


Este caracolito cruzaba mi camino de entrada, muy cerca de mi llanta delantera. —¡No es un buen lugar para pasear, chiquito! — Lo puse en un platito con hojas de toronjil para sacarle unas fotos antes de soltarlo en mi césped, a buena distancia de mis flores.

No le gustó el toronjil, y se apuró a salir del plato, y escapar, deslizándose sobre mi escritorio.


1,2,3: el caracol rayado, Cepaea nemoralis.

#4: Va dejando su excremento en camino.

Nunca antes había observado a un caracol terrestre en el momento de producir sus heces, y me pareció extraño que el excremento salía del sitio donde se encuentra el neumóstomo, el poro respiratorio; este poro siempre se encuentra en el lado derecho del caracol (y también de sus parientes, las babosas), cerca del borde de la concha. Busqué mapas de la anatomía de los caracoles; el ano se sitúa cerca del neumóstomo, pero dentro de la concha.

Pero no veía mal:

Las feces del caracol se emiten del ano, el cual está cerca y conectado con el pulmón y el poro respiratorio. Esto significa que cuando el caracol excreta, lo hace dentro de la concha. Las heces entonces caen desde el poro respiratorio saliendo desde el borde de la concha, y cayendo al suelo o a cualquier superficie en el cual se mueve el caracol. (Garden Tips)

Los caracoles son algo extraño, pero más valía asegurarme. En una página dedicada enteramente a excrementos de caracol, encontré esto:

El poro respiratorio proporciona aire a los pulmones. El ano se localiza en el mismo lado del cuerpo. Así que, además de su uso para propósitos respiratorios, el poro también sirve de punto de salida por donde el excremento del caracol deja el cuerpo. En fin: Los caracoles tienen órganos internos, entre los cuales es el ano, que secreta deshechos digestivos adentro de la concha, no afuera. El excremento, después de salir del ano, se escapa por medio del poro respiratorio y sale por el lado de la apertura central de la concha. (A-Z Animals)

Siempre hay algo más. Mientras buscaba entre diagramas y descripciones de la anatomía de los caracoles, encontré esto:

El sentido de la vista de los caracoles es útil, pero solamente puede distinguir los cambios de la intensidad de la luz, como para saber si es noche o dia. Pueden mover los tentáculos para mejorar la vista. Pero en cambio, son casi totalmente sordos, ya que no tienen orejas ni órganos de la audición. Para compensar esta falta de audición, tienen un "pensamiento" asociativa excelente, lo cual les ayuda a recordar los lugares donde han estado, o donde se encuentran los objetos de su medio ambiente. (Snail World - Snail Anatomy)

Ojalá este caracolito se acuerde de que bajo las llantas de un coche no es buen lugar para pasear.


  1. Lawns aren't very safe habitat for them, because of the lawnmowers.

    1. I hadn't thought of that. Next time I find a snail, I'll move it to a treed area where it is never mowed.

  2. Looks like your guy is a Cepaea nemoralis, a grove snail. They come from Europe originally.


I'm having to moderate all comments because Blogger seems to have a problem notifying me. Sorry about that. I will review them several times daily, though, until this issue is fixed.

Also, I have word verification on, because I found out that not only do I get spam without it, but it gets passed on to anyone commenting in that thread. Not cool!

Powered By Blogger