# why don't pirhanas eat each other **URL:** \ **Category:** Factual Questions\ **Created:** [December 30, 2005, 5:36pm UTC](https://boards.straightdope.com/t/why-dont-pirhanas-eat-each-other/337750 "2005-12-30T17:36:09Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![bigtextu](https://avatars.discourse-cdn.com/v4/letter/b/94ad74/32.png) [@bigtextu](https://boards.straightdope.com/u/bigtextu)\ **Post date:** [December 30, 2005, 5:36pm UTC](https://boards.straightdope.com/t/why-dont-pirhanas-eat-each-other/337750/1 "2005-12-30T17:36:09Z")
thats the question of the ages…any input would be nice. ---
**Author:** ![Speaker\_for\_the\_Dead](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@Speaker\_for\_the\_Dead](https://boards.straightdope.com/u/Speaker_for_the_Dead)\ **Post date:** [December 30, 2005, 5:44pm UTC](https://boards.straightdope.com/t/why-dont-pirhanas-eat-each-other/337750/2 "2005-12-30T17:44:52Z")
For the same reason any pack hunters don’t: survival is based on the group. They might be vicious in their attack habits, but the school is still their social group, and thus off-limits for eating. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [December 30, 2005, 5:58pm UTC](https://boards.straightdope.com/t/why-dont-pirhanas-eat-each-other/337750/3 "2005-12-30T17:58:50Z")
They aren’t nearly as indiscriminate as most people think, anyway. Natives who live near waters populated by piranha know it’s quite safe to wade IF you are careful not to appear to be an injured or weak animal. Fluttering, panicky and uneven movements signal to the fish that an animal is in distress and that’s what triggers an attack. They will very rarely attack a healthy animal–it’s too risky and there’s generally too little gain for the effort, since a healthy animal can usually escape. Avoiding isolated pools caused by drought where a number of fish have been trapped is also advisable, since desperation will force them to attack nearly _anything_ passing through. And no, they cannot strip a horse in minutes. They normally travel in schools of between 30 and 50 individuals, not thousands as often depicted in Hollywood movies. Mostly they survive on smaller animals which are unfortunate enough to fall into the water accidentally. ---
**Author:** ![lissener](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lissener/32/6139_2.png) [@lissener](https://boards.straightdope.com/u/lissener)\ **Post date:** [December 30, 2005, 5:59pm UTC](https://boards.straightdope.com/t/why-dont-pirhanas-eat-each-other/337750/4 "2005-12-30T17:59:02Z")
Zackly. Same as why lions don’t hunt each other, and lawyers don’t sue each other. Well, it’s not a \*universal \*truth, but you get the drift. ---
**Author:** ![lissener](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lissener/32/6139_2.png) [@lissener](https://boards.straightdope.com/u/lissener)\ **Post date:** [December 30, 2005, 6:01pm UTC](https://boards.straightdope.com/t/why-dont-pirhanas-eat-each-other/337750/5 "2005-12-30T18:01:15Z")
> [@Q.E.D.](#): > > They aren’t nearly as indiscriminate as most people think, anyway. Natives who live near waters populated by piranha know it’s quite safe to wade IF you are careful not to appear to be an injured or weak animal. Fluttering, panicky and uneven movements signal to the fish that an animal is in distress and that’s what triggers an attack. They will very rarely attack a healthy animal–it’s too risky and there’s generally too little gain for the effort, since a healthy animal can usually escape. Avoiding isolated pools caused by drought where a number of fish have been trapped is also advisable, since desperation will force them to attack nearly _anything_ passing through. And no, they cannot strip a horse in minutes. They normally travel in schools of between 30 and 50 individuals, not thousands as often depicted in Hollywood movies. Mostly they survive on smaller animals which are unfortunate enough to fall into the water accidentally. Yes; natives swim in those waters pretty regularly. Piranhas mostly eat small fish. They only go after “big game” when they’re starving. ---
**Author:** ![Crandolph](https://avatars.discourse-cdn.com/v4/letter/c/7cd45c/32.png) [@Crandolph](https://boards.straightdope.com/u/Crandolph)\ **Post date:** [December 30, 2005, 6:40pm UTC](https://boards.straightdope.com/t/why-dont-pirhanas-eat-each-other/337750/6 "2005-12-30T18:40:56Z")
Professional courtesy. ---
**Author:** ![nivlac](https://avatars.discourse-cdn.com/v4/letter/n/3bc359/32.png) [@nivlac](https://boards.straightdope.com/u/nivlac)\ **Post date:** [December 30, 2005, 6:47pm UTC](https://boards.straightdope.com/t/why-dont-pirhanas-eat-each-other/337750/7 "2005-12-30T18:47:30Z")
\*\*why don’t pirhanas eat each other \*\* Have you ever tasted pirhana? That’s why. ---
**Author:** ![OliverTwistofLime](https://avatars.discourse-cdn.com/v4/letter/o/b487fb/32.png) [@OliverTwistofLime](https://boards.straightdope.com/u/OliverTwistofLime)\ **Post date:** [December 31, 2005, 9:10am UTC](https://boards.straightdope.com/t/why-dont-pirhanas-eat-each-other/337750/8 "2005-12-31T09:10:13Z")
On a visit to the Amazon last year, I watched children swimming in a tributary off the river with no concern although the waters were full of the Piranhas. I was told that they are pretty benign unless they see blood in the water. The boat guide cooked Piranhas for us to eat…Not bad eating except the fish is so thin, you have to eat a whole bunch of them to satisfy hunger… ---
**Author:** ![KlondikeGeoff](https://avatars.discourse-cdn.com/v4/letter/k/3e96dc/32.png) [@KlondikeGeoff](https://boards.straightdope.com/u/KlondikeGeoff)\ **Post date:** [December 31, 2005, 3:31pm UTC](https://boards.straightdope.com/t/why-dont-pirhanas-eat-each-other/337750/9 "2005-12-31T15:31:55Z")
The posters who pointed out that Piranhas seldom, if ever, attack people or other large animals is quite correct. However, I want to warn everybody about a horrible development with the species that The Government is trying to supress to avoid panic. It seems that vast schools of Giant Africanized Piranhas are rapidly swimming northward. Already they have decimated the manatee population in Florida and the surfer population in Southern California. What is worse, many have mutated and their fins have morphed into legs, and they are invading the entire Gulf Coast. 😃 I’ve got to stop now and finish this script for the next blockbuster disaster movie.