Why do shells have holes

So-called damaged shells have much more of a story to tell than the whole ones do! Thank you for the wonderful post. I enjoyed reading it.

My husband and I arrive in sanibel in 3 days and we are super excited! It is my all time favorite place to be! FYI- Shelling Alert! If they were coming in there, they may have started coming in somewhere else as well.

Enjoy the weekend wherever you might be. I found a shell with a V on it while on Sanibel. Thank you for sharing so much of your shell-smarts with us. Hi there friend:- We made it to Blind Pass because of your post. Huge pile with a lot of happy Shellers. My husband was a foot away from a gentleman who found a gorgeous Junonia. We met another woman who found a Junonia on the Sanibel side…they were out there. It was great meeting you today. We will continue to live here in Sanibel through you.

Lisa B, so very nice to meet you today too!!! We had just talked about Blind Pass and I thought of you when I got there so glad u made it to see the difference.

Fascinating information. Since I just drilled a hundred shells for children to make wall hangers, I will surely pick up shells with holes in the future. Easiest shells to drill are scallops since most others shatter.

Fighting Conchs are also ok to drill. Yep, I learned my lesson — look for shells that already have shells. Hi Marilyn, what tool did you use to drill the holes?? Thanks for the informative post as always! Others you stand an okay chance finding either in capital or lower case form :.

I found this shell on Sanibel this morning at Pointe Santo… It is an ark that has a star that looks like it is stamped right on it. Do you know what could have done this? I am including a picture I took. I am just getting started with collecting. The only thing I know is that I have found these beautiful beach treasures. You answered questions that I wondered about.

Thank you. Your email address will not be published. Notify me of follow-up comments by email. Notify me of new posts by email. For gift tags … And I always love to see someone string them for jewelry… I would have never known where to start finding information on these cool holes in shells if Lisa from Shellabaloo 5 OMG I just realized… both Lisas from different Shellabaloos are fascinated with holes in shells too! Share with your friends! Like this: Like Loading Previous Seashells and Beach Erosion Update.

Loretta on May 16, at am. MurexKen on May 16, at am. Susan H on May 16, at am. Pretty amazing stuff! The drill holes left in fossil shells by hunters such as snails and slugs show marine predators have grown steadily bigger and more powerful over time but stuck to picking off small prey, rather than using their added heft to pursue larger quarry, new research shows. The study, published today in Science , found the percent of shell area drilled by predators increased fold over the past million years, suggesting that the ratio of predatory driller size and tough-shelled prey increased substantially.

The study's authors say the widening gap could be caused by greater numbers and better nutritional value of prey species and perhaps to minimize predators' vulnerability to their own enemies. This gives us the first glimpse into how the size of predators and prey are related to each other and how this size relation changed through the history of life.

Predation is a major ecological process in modern ecosystems, but its role in shaping animal evolution has been contentious, Kowalewski said. This study sheds light on predation's ability to drive evolutionary changes by supporting a critical tenet of the escalation hypothesis: the idea that top-down pressure from increasingly larger and stronger predators helped trigger key evolutionary developments in prey species such as defensive armor, better mobility and stealth tactics like burrowing into the sea floor.

Other than a few rare finds of predator and prey preserved mid-battle, a lack of direct fossil evidence has hindered a clearer understanding of how predators have influenced other species' evolutionary paths. Adiel Klompmaker, then a postdoctoral researcher at the Florida Museum, was working on a database of drill holes -- the marks left in a shell by a predator such as a snail or slug -- when he saw their untapped potential as "smoking gun" evidence of deadly saltwater dramas.

Drilling predators such as snails, slugs, octopuses and beetles penetrate their prey's protective skeleton and eat the soft flesh inside, leaving behind a telltale hole in the shell.

Trillions of these drill holes exist in the fossil record, providing valuable information about predation over millions of years. But while drill holes have been used extensively to explore questions about the intensity of predation, Klompmaker realized they could also shed light on predator-prey size ratios.

Just as a bullet hole indicates the caliber of gun fired, a drill hole points to the size of the predator that created it -- regardless of what kind of animal it was. By compiling these hole sizes, researchers can gain insights into million years of predator-prey interactions. To determine whether drill hole size is a good predictor of the size of the animal that made it, the researchers compiled measurements of predator sizes and the diameter of the holes they produced.

Its tongue, called a radula, is specially designed for this purpose. It is a ribbon of tiny teeth that are rubbed back and forth across the shell. The work of the radula is aided by acidic secretions that soften the shell. Once the hole is complete as shown in the picture below, the Moon snail delivers its digestive enzymes into the bivalve, breaking down the bivalve so that the moon snail can suck it up through the hole.

That all sounds very one-sided in favour of the moon snail! However, if you collect enough bivalve shells you will find some with incomplete holes as in the picture below!

This means the bivalve has managed to escape the clutches of the moon snail before it can be eaten. Some shells have grooves across their surface showing how the bivalve slowly wriggled free of the moon snail while the radula continued to carve away at its shell!

This following clip shows some different shells with holes in them. View all posts by: Jacqui Younger. Weekly Creature Feature: How did these shells get such perfect holes? Jacqui Younger. Comments are closed.