At a maximum size of about 60 cm (24 inches), the Horse Conch, Triplofusus giganteus (Kiener, 1840), is the largest marine snail living in the Atlantic Ocean. Horse Conchs are known to feed on a number of other mollusks, including Lightning Whelks, Tulips, Fighting Conchs, large clams, and others. In this great photo by Amy Tripp, taken at low tide near Kice Island, Florida, a Horse Conch (let’s call it “Mighty”!) is about to pounce on a stranded Lightning Whelk. The Horse Conch’s siphon can be seen lining the shell anterior canal. The head is visible atop the large foot, which is starting to grab the whelk. Horse Conchs use their foot to completely envelop the prey prior to feeding. This smothering behavior triggered the local conventional wisdom that Horse Conchs kill their prey by asphyxia. While it is true that the conch’s tight embrace isolates the prey from its immediate environment, it is also possible that this is used by the conch to create an isolated “death chamber” that focuses and expedites the action of relaxing or paralyzing substances secreted by the predator prior to feeding. Read more about mollusks and their shells in the Museum’s Southwest Florida Shell Guide and Shell Blog.
