Hungry Mouths, Part 2 - Piranha Boogaloo (The Most Misrepresented Fishy?)

Piranhas have one of the worst reputations amongst our fishy friends, but is it deserved?

Strangely enough, we may have Teddy Roosevelt to thank for these fish being unnecessarily ill-regarded.

Local folk heard the president and author was coming for a visit, so they netted a bunch of piranhas and held them for a number of days without food so they could give Roosevelt quite the show. The starved fish devoured a cow lowered in the water in mere moments! Roosevelt took this story back to America and his stories of these voracious fish spread far and wide.

Most piranha are omnivorous, eating what is available, not needing live prey. Most of the meat they eat is carrion, and they just as happily eat other things. Some species, and especially their cousins, the pachu, are either strictly or almost exclusively vegetarians.

While they have the strongest bite force of any animal (scaled, of course) if we think about it, flesh is relatively easy to bite through. But for eating tough and fiberous vegatation and unpeeled fruits, all of a sudden, sharp and strong jaws make a bit more sense.

Some fun piranha facts:

Some piranhas prefer to eat not whole fish, but just the scales of other fish! They are shiny and attractive, and covered with nutrient rich secretions of the host fish. They will charge and give the target fishy a strong whack, but other than having to grow back a few missing scales, the fish gets away just fine and the piranha gets its prize.

They stay in large groups, not for feeding frenzies, but for protection. They are far from apex predators, having many other fish, birds, crocodiles, and people that will gladly eat piranha. The larger and older fish stay near the middle of the huddle, while the young are the cannon fodder. Studies have been done on the fish stress levels by using a (fake if I'm remembering right) cormorant and examining their breathing response.

Piranha shed their teeth, but not individually like shark, they do it in sections, about a quarter of the jaw at a time.

For some more neat facts and further details, see my links above, see this Smithsonian list of 14 piranha facts, or here is the video I watched last night to inspire this post.