Tuesday, May 27, 2014

Snails that eat Starfish! Predation in the tropical Indo-Pacific!

In cold and temperate water habitats, starfish, especially asteriid starfish are often predatory. ESPECIALLY on mollusks! Famously on bivalves and clams but also quite a few gastropods aka snails.
But in the tropics, we often find the tables are turned! Snails, especialy giant snails, such as these Giant Tritons (Charonia sp.) are big, ol' meanie predators on several often, equally large and heavily armored (or at least well-defended) starfish species...

The Triton Vs. Crown of Thorns (Acanthaster planci
Just walked out of Godzilla and want to see two big monsters fight it out?? You've come to the right place!

The "Triton's Trumpet" is a large snail with a shell that is often up to two feet long. Because it is large and showy, it is often sought after as a souvenir.   Here we have not one but TWO videos of these giant snails attacking the very spiny Crown of Thorns starfish, a voraceous predator of corals

When the snails get to work, they often appear to be successful. But even if not, with the crown-of-thorns starfish there's *literally* many more fish (or starfish) in the sea!

this did not end well for the starfish.

The Triton vs. the "Blue Linckia" aka Linckia laevigata
Here..what you are seeing is NOT a hermit crab, but one of these giant triton snails finishing off its dinner, a blue Linckia laevigata, eating it disk first with the legs sticking out of the shell's opening..

Here's what this looks like with a bit more perspective...

The Triton vs. the Cushion Star (Culcita novaeguineae)
Another target species?  The big, round, almost pillow shaped starfish Culcita novaeguineae!

A pic to give you some perspective...

Other Indo-Pacific species include Choriaster granulatus 

Nardoa novaecaledoniae (Ophidiasteridae)

And in the Atlantic Caribbean (Cozumel), this "triton" snail attacking the tropical Oreaster reticulatus.  Honestly, I'm not sure if I've ever heard of this.. maybe something new? Will have to check...

Attacking a small specimen of Oreaster.. maybe O. clavatus?
via Wikipedia from NOAA photo library
And of course, its not always, the BIG snails.. the tiny ones can be predatory as well.. Here are individuals of Phos nodicostatum (Buccinidae) feeding on the arm of a crown of thorns..

NEXT UP! Pt. 2 to this.. SNAIL PARASITES!! 


lazyi said...

Aloha Chris,

I am glad i found your blog. I live in Hawaii. I notice that horned helmet shells (empty and live ones)have large holes which i believe to be predators other than humans, under water where i found them. Who are their predators, or who makes these holes to get at them? Mahalo

ChrisM said...

Hmm..well, you are on the right track. That sounds like snail predation but off hand I'm not sure which one.

I will look around.