Danger! Snail On The Prowl
By Bill Frank
Euglandina rosea (Férussac, 1821) Rosy Wolfsnail - Mating

A pair of Euglandina rosea (Férussac, 1821) mating

    Here in northeast Florida the temperature has warmed considerably over the past month, spring is in the air, and quite likely there is a sex-charged killer is lurking outside your door. This fearsome beast is none other than the Rosy Wolfsnail [Euglandina rosea (Férussac, 1821).
    Euglandina rosea is the largest terrestrial snail found in northeast Florida and is the only of our recorded 70 native species which feeds on other snails. The natural range of this species is the Southeast United States where it can grow to a length of over 60 mm. Henry Augustus Pilsbry (1946 - Land Mollusca of North America (North of Mexico)) recorded a 76 mm. specimen from Palatka but normally the specimens found locally are much smaller (40-50 mm. range). Long recognized by man for its prowess in hunting down and killing other snails, Euglandina rosea has been intentionally introduced to a variety of islands in the Pacific and Indian Oceans, Bermuda, and the Bahamas ostensibly to control undesirable snail species such as the Giant African Snail [Lissachatina fulica (Bowdich, 1822)]. To put it succinctly, these introductions haven’t worked out as they were envisioned. The Euglandina have been blamed for the extinction of endemic species and have been heavily implicated in the extinction or at least decline of other species of snails wherever they have been introduced, notably in Hawaii.

Euglandina rosea (Férussac, 1821) Laying Eggs

Euglandina rosea (Férussac, 1821) Eating

Laying eggs

Eating a Bradybaena similaris

    Considering all the tales of woe associated with this species, one might be inclined to believe that the lawns and forests of northeast Florida are literally over-run with Euglandina. However, based upon the experiences of this scribe, that is certainly not the case. In fourteen years of “snailing” my extensive yard as well as those of my neighbors and other adjacent environs, less than two dozen living specimens have been found. Whether this low number found is a result of them being somewhat rare or because they keep a low profile, is not entirely clear at this point.
    My latest foray into the world of the Rosy Wolfsnail began during a balmy evening this past March on my front patio when in the darkness I kicked “something” crawling across the outdoor carpet. Fortunately, this “something” turned out to be an adult Euglanding rosea and not a “something” which bites. From past experience I knew that when one finds a single Euglandina on the prowl there are likely others nearby. This was born out soon enough when two additional specimens were quickly located in other parts of the yard. The threesome was transferred to a covered bucket for storage while a five-gallon terrarium was prepared for more permanent observations.
    Far from being stressed by their temporary new home, the Euglandina immediately seized on the opportunity of like companionship by immediately mating. This is an observation I’ve made in the past when I was fortunate enough to have collected a pair at the same time. The actual mating is usually preceded by some tentacle waving and caressing – a mating ritual of sorts.
    Through diligent searching over the following week, two additional Euglandina were found and added to the terrarium. With each new terrarium introduction, the established residents mated with the newcomers. While most mating events involved two snails, threesomes were also observed.

Deroceras laeve (Müller, 1774) Meadow Slug

Bradybaena similaris (Férussac, 1821) Asian Tramp Snail

Meadow Slug Asian Tramp Snail
[Deroceras laeve (Müller, 1774)]  [Bradybaena similaris (Férussac, 1821)]
    Keeping the five fed has proven to be a daunting task – especially with the year’s dry weather. My success in finding the Euglandina is more than likely due in part to the fact that my immediate neighborhood is over-run with the alien Asian Tramp Snail [Bradybaena similaris (Férussac, 1821)]; a medium sized (up to about 12 mm.) species. This species has proven to be the Euglandina’s preferred prey. Despite the fact that Assistant Editor Harry Lee has dissected the guts of Euglandina and found the remains of our local small Meadow Slug [Deroceras laeve (Müller, 1774)] and other small snails, my fearsome five have ignored the Meadow Slugs and smaller snail species that they were offered preferring instead the Bradybaena.
    Observing the Euglandina on the prowl for food is a study in efficiency. Their ability to quickly find the prey combined with their speed (yes some snails are rather quick) makes the whole event rather brief and showcases all the traits which led to their ill-advised world-wide introductions. In the case of the Asian Tramp Snails, they are reduced to an empty well cleaned shell in minutes. No matter how many live specimens were introduced into the terrarium prior to my retiring for the night; only empty shells remained the next morning.
    Considering that the group spends an inordinate amount of time tending to the business of reproduction (as well as feeding), I’m hoping that in the future that eggs and baby Euglandina may be on the agenda. Only time will tell.
    Club member Carol Ruckdeschel of Cumberland Island, Georgia reports that Euglandina are quite common on the island, and she has found their eggs, with calcareous shells similar to those of lizards, for which she initially mistook them.