Shocking Truth About Piranhas Revealed!
In
the languid news week after Christmas, hungry media outlets swarmed
over a report of piranhas attacking swimmers on a river in Argentina.
“Massive Piranha Attack” cried The New York Post. “70 Christmas Day
Bathers Are Savaged” added The Daily Mail, promising “the truth about
the fish with a bite more powerful than a T. rex.” ABC News called it a
“Christmas Day feeding frenzy.” In fact, the injuries ranged from minor
cuts to at least one missing finger part — not exactly as newsworthy as,
say, the 800,000 Americans who require medical treatment for dog bites
each year.
.
Piranhas
have always been among our favorite subjects for sheer, sputtering
nonsense. Theodore Roosevelt, on a 1913 expedition in South America,
called piranhas “the most ferocious fish in the world.” More recently,
multiple “Piranha” movies have ridden this hysteria to the bank.
.
This
is an awful lot of hype for piranhas to live up to, and predictably,
they disappoint. To test the colorful mythology of the ferocious
piranha, I once climbed into a tank of hungry red-bellied piranhas at
the Dallas World Aquarium. (They fled to the opposite corner.) In the
Peruvian Amazon, I stood waist-deep in the Rio Napo while catching and
releasing piranhas on a hook-and-line. (The nibbles were strictly of the
usual kind.) In the flooded grasslands of Venezuela, I drove around
tossing a chicken carcass into various bodies of water to time how long
it took for the flesh-maddened swarms to strip it to feathers. (There
was enough chicken left at the end of the day to feed a family of four.)
.
The
point of this exercise, recounted in my book “Swimming With Piranhas at
Feeding Time,” was that piranhas do that swarming, blood-crazed,
flesh-ripping thing only in a couple of rare circumstances, both
involving a highly concentrated food source: They will swarm around bird
rookeries, where the fledglings leaving the nest often tumble straight
down into the water. And they’ll do it around docks where fishermen
clean their catch and heave the guts into the water.
Otherwise, you can swim without fear.
.
I
didn’t worry about piranhas, for instance, when the only place to
bathe, on a recent trip deep into the backcountry of Suriname, was the
river running past our camp.
Then
one day, sitting in a canoe, I watched the fish biologist on our
expedition, Jan H. Mol of the University of Suriname, pull a
12-inch-long black piranha out of the same water where we took our daily
baths. As this extremely toothy creature wriggled in his hands, Mr. Mol
started talking, in his somewhat ponderous way, about a paper he had
published on piranha-bite incidents, complete with color photos of
amputated toes.
.
Like
me, Mr. Mol believes the piranha threat is wildly exaggerated. He has
spent more than 20 years wading in South American rivers and hauling up
every imaginable fish without ever being injured by free-swimming
piranhas. “Free-swimming” is, however, the operative phrase there: If
you get careless while trying to untangle one from a net, or you let one
flop around the bottom of the boat, things can get painful.
. .
As
he spoke, Mr. Mol was using the soft pad of his index finger to hold
down the piranha’s sharply serrated lower jaw and give me a better view.
It was a formidable mouthful. But that index finger rather spoiled the
effect of another recent study, in the journal Nature, which found that
the black piranha’s bite is more powerful, pound for pound, than that of
a great white shark or a killer whale. Yes, yes, that article also
mentioned T. rex, but “pound for pound” (or as the authors put it,
“removing the effects of body size”) turns out to be another of those
pesky operative phrases.
.
We
chatted briefly about the classic studies by the Brazilian researcher
Ivan Sazima, who observed piranhas in the clear-water ponds and creeks
of South America’s vast Pantanal wetlands. Mr. Sazima found that these
generally timid little fish mainly feed by nipping off fins and scales
from passing fish, not by ripping their flesh. Mr. Sazima is also an
author of a paper with the lovely title “Scavenging on human corpses as a
source for stories about man-eating piranhas.” It concluded that when
human bodies turn up in the water with signs of piranha attack, it’s
almost certainly because the piranhas were scavenging on people who were
already dead.
.
Even
piranha specialists would struggle to come up with a dozen cases over
the past half-century in which multiple living human victims were
injured. In the two cases Mr. Mol investigated in northwestern Suriname,
one in the 1950s and the other in the early 2000s, most of the victims
suffered a single relatively minor bite on the feet or legs. He found
that in each case, there was a factor that attracted piranhas to the
area — fishermen gutting their catch nearby or holiday visitors spilling
food in the river. Mr. Mol theorized that the piranhas bit humans by
accident at first, and then, recognizing a newly abundant food source,
began to take advantage of it. Other fish specialists I spoke to or
emailed the other day argued that those incidents, and the more recent
one in Rosario, Argentina, were all cases of defensive biting.
.
Christmas
Day was unusually hot in Rosario — about 100 degrees Fahrenheit — and
people were crowding into the river. It’s also mating season for the
three local piranha species. It’s likely, said Prosanta Chakrabarty, a
fish biologist at Louisiana State University, that bathers inadvertently
wandered into male breeding territories, provoking a brief but hostile
response.
.
None
of the attacks escalated into a classic piranha swarm. It wasn’t, as
The Daily Mail reported, “like a scene from a horror film” with swimmers
being “savaged by shoals of the razor-toothed fish,” which ripped away
“chunks of their naked and exposed flesh.” Victims were able to walk
back to the beach without being attacked by other piranhas. Other
beachgoers were back in the water a half-hour later.
So
what’s the bottom line on piranhas? “If something is potentially
dangerous to humans, it will be dangerous in certain conditions,” Mr.
Mol told me, as we sat in the canoe that day in Suriname. But those
conditions are extremely rare, and the danger tends to be highly
limited.
.
We ate the piranha for dinner that night, and I continued to bathe in the river.
But — this is the thing about human nature — now and then I also paused to count my toes.
.
Richard Conniff is the author of “The Species Seekers: Heroes, Fools, and the Mad Pursuit of Life on Earth.”
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