31 October 2013
Decades ago, the film, Jaws, was credited with
terrifying movie goers to the point that they avoided beaches for fear of being
attacked by a real version of the film’s animatronic great white shark. [image]
[1] Then, there was
a sequel with promotional trailers warning: “Just when you thought it was
safe to go back in the water.” [image]
But at least you were safe on dry land. Right?
Saturday Night Live’s writers decided to take away that
last refuge of safety by presenting a predator that could strike on land or
sea. In 1975, the first in a series of SNL sketches featured a
hapless urban dweller who hears a knock on their front door.
When the caller is asked to identify themselves, a voice on
the other side of door says “repair man” or “door-to-door salesman.”
Then, when the door is opened, in plunges the “Land Shark” (or a giant foam
rubber version of the “Land Shark”), which completely consumes the victim. [2]
[image]
[video]
Well, the Land Shark was just a joke. Wasn’t it?
It was. But, like more than a few fictional, on-screen
characters, the Land Shark seems to have an imitator.
Just when you thought it was safe to go near the
water?
Catfish in France have learned to hunt pigeons. [3]
[4] Fishermen
on the France’s River Tarn were more than shocked to witness catfish “loitering
in shallow water near sandbars populated by pigeons.” When one of the
birds wandered too near the water line, it was a “Land Shark” experience for
the bird and a meal for the catfish. [video]
When Julien Cucherousset of Paul Sabatier University heard
the story from the bewildered fisherman, he captured footage of the “event.”
The on-line video went viral. The first time I saw the video, my
reaction was almost that of an academic naturalist. “How fascinating,” I
thought.
At least, I thought it was fascinating until I learned that
these catfish were three to four feet long. So, I am only about 2 feet
longer that the largest of these “Land Catfish.” My next thought?
Would I . . . ? Yes, I assured myself. I’d win — if
caught in a shoreline struggle with an overly aggressive four-foot
catfish. Then, I reflected. Suppose I was sick and weak that day?
I didn’t try to answer that question. I just . . . thought of
something else. [5]
At first, I was comforted by the fact that this particular
species of catfish wasn’t native to France, but had been introduced to the Tarn
River about 30 years ago. I imagined some weird, predacious species of
catfish from the depths of the Amazonian jungle had been imported and
accidentally released into the river. But, when the full story unfolded,
it turned out that these were just plain old catfish. And they had been
intentionally released into the river. [6]
Over the last three decades, the waters of the Tarn became
less populated with crayfish and other smaller fish. So, the catfish
began feeding on land prey — a behavior no member of its species is known to
have engaged in before. These fish hover under the water near the shore
watching their prospective, terrestrial prey. Then, when an opportune
moment presents itself, they leap out of the water onto the dry land, grab
their prey, and leap back into the water taking there land-dwelling victim with
them. Then, the “Land Catfish” enjoys a leisurely meal in its underwater
home. [7]
Autopsies of the catfish in the area revealed that not all
of the fish were eating pigeons. However, those that were tended to
abandon their old diet of crayfish and other small fish focusing more
exclusively on land prey. [8]
Somehow, I found the casual way in which these animals
extended their hunting range disconcerting. But more disturbing was
the autopsy’s suggestion that some fish had developed a taste for land animals
— ignoring their old fare of crayfish and other small fish to focus almost
entirely on pigeons. As a land-based mammal who enjoys strolling along
the shores of natural bodies of water, I’m still not entirely comfortable with
these developments.
One writer, attempting to minimize the strangeness of it
all, noted that African crocodiles jump out of the water and grab
zebras. And whales beach themselves on the ice to nab penguins for
dinner. But these are hardly apt comparisons. Crocks and alligators
are air-breathing lizards. They just hang-out in the water. Whales
are also air-breathing mammals who have adopted a fish-like lifestyle. [9]
Neither of these examples could compare to a plain old fish
intentionally jumping out of the water to grab some terrestrial creature, drag
it into the water, and eat it. I’ve watched scenes like this in old
horror movies. I’ve always loved to stroll along the shore of almost any
waterway, but is it safe? Where I live, my favorite body of water is the
Mississippi River. After seeing this video, I checked. The
Mississippi is teaming with catfish – those same enterprising, opportunistic,
and hungry sea-beasts that are scarfing down pigeons in France!
On calmer reflection, I realized that the Land Catfish is
actually engaged in the mirror image of human sea diving. Somehow, I’d
always thought that land creatures dived into the water to feed on unsuspecting
sea creatures. Not the other way around. And human beings had
the distinction of being the only creature that could learn to dive into the
water for food (and maybe a few pearls). Now, the Land Catfish has turned
the tables on us.
But the Land Catfish isn’t the only sea creature that feels
free to promenade out onto the dry land to pick up a meal.
A few decades ago, I remember strolling along a Sarasota
beach at midnight — my feet kicking through the white sand. In those
distant days, you could still find yourself quite alone on the beach at
night. Absolutely taken with the beauty of the Gulf, I remember thinking
how nice it would be to just stretch out on the sand and sleep in the
cool breeze off the water until sunrise.
All those years ago, I would still have been quite safe from
human interference, but I would never have thought of the possibility of
something coming up out of the sea. I can imagine the psychological
trauma I would have experienced if, in the middle of that peaceful night’s
sleep, I had stirred awake and opened my eyes to see an eye looking back at
me: the “dominant eye” of a local octopus.
The
creature wouldn’t have been interested in me. It would have just been
“passing by.” But, after an experience like that, I would have moved to
the top of a mountain — as far away from the water’s edge as I could get.
Not long after I saw the “Land Catfish” video, a story broke
about a “Land Octopus.” The terrestrial excursions of the octopuses have
stayed pretty much out of the public eye until recently when one of these
strange creatures was caught in the act – on video. [video] An octopus
was seen grabbing lunch, not while roaming where it belongs – underwater —
but, instead, crawling around on the beach casually grabbing a few
snacks. The witnesses got a video camera and the rest is internet
history. [10]
How long has this sort of thing been going on, I
wondered? Well, octopuses have been doing this since . . . forever.
The Land Octopus starring in the San Mateo County,
California video was not engaged in any particularly unusual behavior.
Marine biologist James Wood explained that several species of octopuses make
brief forays onto land for a meal. [11]
Most discomforting was his explanation of why the public is so ignorant of this
particular octopus behavior. Octopuses leave the water all the
time. They just do it when they won’t be seen. Wood explained that
most octopuses are nocturnal, sneaking out of the water at night to enjoy their
meals unobserved. [12]
Well, with this factoid, my nocturnal seashore walks are over.
The octopus caught on video was probably engaged in the
octopus version of grocery shopping. Julian Finn, a senior curator of
marine invertebrates at the Museum Victoria in Australia explained that
octopuses frequently emerge and hunt in tidal pools when the tidal waters
recede. The octopus examines these “grocery shelves” either with its
eyes, (octopuses have rather good vision), or feel for food with its
outstretched arms (tentacles?). [13]
However, not so typically, the cephalopod shopper in this
video is seen discarding an empty crab shell during its shopping spree — after
eating the occupant. Either this octopus was particularly hungry and
couldn’t wait to get home, with the crab serving as a kind of fast food snack
or, even with eight arms, carrying all those groceries got to be too
taxing. If the “groceries” get too heavy, octopuses often stop and eat
their way to a lighter load. [14]
However, shopping isn’t the only thing that brings octopuses
out of the water and onto dry land. Finn explained that octopuses also
“lurch” out of the water onto land to escape danger. Wood recalled an
incident in which he was chasing and photographing a common octopus “when it
crawled out of the water, across eight feet of rocks and went back into the
water” apparently hoping this maneuver would confuse the pursuing photographer.
[15]
Mercifully, octopuses aren’t interested in eating
people. Hostile interactions between octopuses and people happen when the
octopus perceives a person as a threat rather than as a potential meal.
Still, even if I’m not on the menu, I wouldn’t like to
encounter an octopus as I was strolling or resting on dry land. Imagine
if I’d paused to catch my breath on that eight foot expanse of rocks when the
Land Octopus jumped out of the water in its attempt to shake the pursuing James
Wood. After literally running into an octopus on dry land, you can bet
that it would be a long time before I thought it was safe to go
anywhere near the water.
Mark Grossmann of Hazelwood, Missouri & Belleville,
Illinois
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