Tag Archives: rosy wolfsnail (Euglandina rosea)

Meet Rosy

I met a stranger one morning.  I call her Rosy.  Some might call her The Plague or The Pestilence or more accurately, The Destroyer of Dawdlers.  Let me introduce you to her.

A close-up of a rosy wolfsnail (a.k.a. cannibal snail; Euglandina rosea) (2009_05_03_017028)

That’s Rosy’s look of consternation.  She displayed it each time I moved her.  Or when I got too close.  Or when I took a profile shot, something she hates because it makes her look translucent.  She thinks opaque is more her style.

Rosy’s a little tiger.  Actually, she’s more a wolf—a rosy wolfsnail (a.k.a. cannibal snail; Euglandina rosea).  She’s native around these parts.  In fact, she’s endemic from Latin America into Texas and east along the Gulf of Mexico to Florida.  She even has a minor presence from Georgia to North Carolina.

I discovered Rosy on my patio.  She was hunting these:

A tiny baby snail in the palm of my hand

No, she wasn’t hunting my hand.  Silly, silly people…  She was hunting the tiny baby snail I’m holding.  Several dozen of these minuscule mollusks had climbed my patio fence to seek shelter from the rising water created by severe storms.

As I investigated the scene, I found Rosy searching for prey at the bottom of the fence.  I promptly decided she needed her portrait taken.  So I fetched her from the damp earth and put her atop the wooden latticework where I could more easily snap a few images—or at least where I could take pictures without having to kneel under a tree during a thunderstorm.

A rosy wolfsnail (a.k.a. cannibal snail; Euglandina rosea) crawling along the edge of my patio fence (2009_05_03_017070)

Rosy happens to be a voracious predator.  She and her ilk have endangered and wiped out native snail species around the globe where she’s been introduced.  Why did we provide free first-class air travel to exotic locales, plenty to eat both on the way and upon arrival, and lots of siblings to play with once she reached her various destinations?  In feeble attempts to control the likewise introduced East African land snail (a.k.a. giant African land snail; Achatina fulica).  We humans are so daft, are we not?  That idea was akin to dowsing a fire with gasoline.

Like wolf spiders and their canine namesakes, she gets her moniker by actively chasing down and overcoming prey.  Obviously she’s chasing other snails, otherwise she’d be an evolutionary failure.  She moves at a snail’s pace while looking for clues that will lead her to lunch: the mucus trails left behind by snails and slugs.  Once she finds such a path, she no less than doubles her speed to catch up with the unsuspecting critters.  And under the best circumstances she moves five times faster than other snails.  She’s the hare to their tortoise, albeit one that remains painfully slow from our much larger vantage.

A rosy wolfsnail (a.k.a. cannibal snail; Euglandina rosea) climbing on top of another rosy wolfsnail (2009_05_03_017185)

Rosy is nicknamed the “cannibal snail” not only because she eats other snails, but because she has no problem eating her own species.  It’s common for hatchlings of her kind to seek out and consume smaller or slower siblings.  Late bloomers are toast.  But later in life she’s less inclined to eat her own and more inclined to mate with them.  You see, she’s a cross-fertilizing hermaphrodite: she can do the dirty with any other wolfsnail, and that can result in one or both individuals becoming pregnant.  Usually, though, the smaller one gives up the goods to the larger one and lets her play housewife on her own.

Rosy is an equal opportunity huntress: she takes out snails of any size.  She can manipulate larger snails into positions that allow her to nibble their tender bits, and her body shape empowers her to reach into their shells to fetch the next bite.  Yes, she does have a slender figure, does she not?  And unlike we humans, she maintains that figure no matter how much she eats.  (It’s okay to be jealous.)

But Rosy needs to consume snails whole if she’s to continue expanding her own domicile.  She metabolizes the homes of others and recycles the shell material for her personal building efforts.  Hence she failed to control the African snail she was introduced to kill.  To keep growing, she ate more of the smaller native snail species than she did the larger invaders.  Oops!

A rosy wolfsnail (a.k.a. cannibal snail; Euglandina rosea) crawling along my patio fence (2009_05_03_017155)

She’s been introduced in places like Hawai’i, Japan, Guam, Madagascar, Sri Lanka, Bermuda and at least a dozen other places.  What a horrible mistake.  Instead of doing what we wanted her to do, Rosy set about causing the extinction of other snail species whilst pretty much ignoring the job description we’d laid out for her.  She can be rather contrary.

She’s also a prolific breeder.  Rosy can multiply her numbers up to five times more quickly than most of the snails she hunts.  Mind you, her own cannibalism somewhat tempers those numbers, but her adaptability and her proclivity to procreate at high volume means she’s a menace in ways our silly ape minds never imagined when we begged her to clean up the other messes we’d made.

Rosy can grow to be a large gal.  A few years ago I found one of her ancestors on my patio who was about five inches/12 centimeters long with a shell about three inches/seven centimeters long.  That version of Rosy later perished of a self-inflicted shell wound after falling off the patio wall.  Very unfortunate…

A rosy wolfsnail (a.k.a. cannibal snail; Euglandina rosea) crawling along the side of my patio fence (2009_05_03_017053)

After our little photo session, I let Rosy go.  Well, her and Rosy 2.0, the second wolfsnail that sneaked up on us while I was entranced by another shiny bauble that caught my eye.  (It was a mushroom, damn it, if you must know.  Like a ferret, I’m easily distracted by the next trinket, the next sparkly thing.  So sue me.)

Since Rosy and her kith and kin are native to my area, I felt no shame in releasing them so they could continue their search for breakfast.  Meanwhile, I grabbed a bit of puddle water and rubbed down the base of the fence.  To give the baby snails a chance.

— — — — — — — — — —

One thing that makes Rosy so unpopular is that she ranks #35 on the Top 100 List of Invasive Species.  She’s responsible for causing the extinction of all native tree snails in French Polynesia.  She’s also done in most of the native land snails in Hawai’i.  And that’s just two of the many places where she’s been introduced.

Rosy’s designation is that of a terrestrial snail.  While taxonomically that’s correct, no one told her about the limitation.  Fast on the ground, she’s also fast in the trees and underwater.  She didn’t exactly sit at the base of trees in French Polynesia tapping her pseudopod waiting for lunch to come to her.  She climbed those trees and ate the snails she was hunting.  Likewise, she has no problem following and consuming lunch below the surface of aquatic habitats.  Did I already mention she’s an equal-opportunity killer?

But even monsters like Rosy come from a place where they’re native, and destructive critters like her don’t lose their homeland beauty simply because we’ve let them loose in places where they promptly devastated the local ecosystem.  Remember this: She didn’t swim to Japan or Madagascar or Hawai’i, and neither did she hitch a ride to those places unbeknownst to us.  We took her there, along with a bunch of her friends and family, and we set her free.

Mind you, had I photographed her in any of the places where she’s wiped out or endangered a great many native species, the tone of this entry would have been a wee bit different.

[cross-posted to The Clade]

Aliens abound in this corner of the universe

Perhaps not so much aliens as alien, as in alien things.

We the occupants of North Texas were blessed recently with a bit of dry air that helped reduce the overnight temperatures dramatically, so mornings around these parts have been cool and comfortable.  It is in stark contrast to the hot and humid mornings we just left behind and will again meet in just a few days.  That means we enjoy it while we can.

Knowing it was more than pleasant outside, I stepped out to the patio early in the morning for a bit of fresh air.  I already fed the various outside cats and visited with those who graced me with their presence.  That meant I was on my own to enjoy the unseasonably cozy weather sans interruption or obligation.

With a cup of coffee in tow, I stood quietly and listened to nature as it likewise started its morning.  This is one of the great pleasures of living right here on the lake: I need only step through the door to be surrounded by wildlife and natural beauty (or, at the cost of only a minute or two, I can walk down to the lake to be completely separated from the urban landscape).

Birds were singing their good mornings and beginning to fill the sky with activity.  Aside from that, very little was happening, and that didn’t bother me a bit.

As I stood absorbing my surroundings, my eye chanced upon a very large shell of some kind resting on the bottom of the fence.  It was approximately 2 inches (5 centimeters) long and 1.25 inches (3 centimeters) wide.  (Note that width in this case refers to the diameter of the shell, so it also indicates its height.)  The color was a dead-leaf brown in the shadows of morning.

I approached the shell to investigate as it was rather large, and it was then I noticed a large snail pulling it along as he made his way toward the patio floor.  It amazed me to see such a large snail—he was at least 5 inches (12.5 centimeters) long and half an inch (just over a centimeter) wide.  His movement was unhurried to say the least, at least in that way for which snails are known.

Insomuch as just the day before I spread Sevin dust around the inside perimeter of the patio fence to halt the ant onslaught, watching this enormous creature work his way slowly toward that thin line of death caused me to pick him up and move him so that he would not come into contact with the barrier.  While I was at it I decided I might as well get some pictures, so I set him upon the fence and snapped a few, followed by capturing some video of the beast.

During this brief session, I noticed another one of the same species, albeit about half the size of the first one.  The second snail was making its way up the fence in the corner.  Deciding both were in danger on the patio due to the insect toxin, I fetched the newcomer and set them both down by the tree outside of the fence.

Only later did I identify the slimy visitors as rosy wolfsnails (Euglandina rosea).  They are nicknamed cannibal snails because they are carnivorous; they eat other snails.  They are also the largest native species of land snail in North America and the second largest in the world.  They rank in the top 100 list of invasive species and are responsible for the extinction of innumerable snail species around the globe.

Had I known all of that before letting them go, instead I would have preferred to put them together and let them duke it out (wouldn’t that have made for some interesting photos and videos…).  Sadly, I didn’t know any of this until it was too late.  You see, one of my nightly visitors (most likely a raccoon or opossum) ate both snails overnight and left their damaged shells right there for me to see.  Oh well.

In any case, here’s one of the photos I took.  There are more below the fold.  I will also post one or two videos of this behemoth as soon as I get them edited and ready for consumption.

What you’ll notice is the six tentacle-like protrusions on its head.  Two of those are actually its mouth (the two at the bottom).  You’ll better appreciate those once I get the videos posted as they’re fascinating to watch.

Close-up of a rosy wolfsnail (Euglandina rosea) (148_4895)
Rosy wolfsnail (Euglandina rosea) (149_4914)
Rosy wolfsnail (Euglandina rosea) (149_4909)
Rosy wolfsnail (Euglandina rosea) (148_4899)