# Capsaicin and evolution **URL:** \ **Category:** Factual Questions\ **Created:** [May 14, 2014, 2:53pm UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438 "2014-05-14T14:53:17Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [May 14, 2014, 2:53pm UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/1 "2014-05-14T14:53:17Z")
In a recent thread on [How do we feel heat?](http://boards.straightdope.com/sdmb/showthread.php?t=723398), engineer\_comp\_geek said : > [@How do we feel heat?](https://boards.straightdope.com/t/how-do-we-feel-heat/688430/2): > > TRPV1 also reacts to capsaicin, which is why hot peppers feel “hot” to us. Many animals lack the TRPV1 sensor and can eat hot peppers without feeling the “hot”. The way I understood this situation was that pepper plants evolved to have capsaicin in the fruits - so that animals that help propagating its seeds did _not feel the heat_ and other animals _felt the heat_. Did I get this correct or did peppers always had capsaicin in them and it was actually the animals who evolved to \*not feel the heat \*? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 14, 2014, 3:05pm UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/2 "2014-05-14T15:05:13Z")
You have it correct. It’s basically mammals who are sensitive to it and birds who are not. I expect most other animals aren’t sensitive either, but most fructivores are birds and mammals. While there might be some evolutionary pressure on an animal to become desensitized, as long as there are plenty of other non-spicy food sources the pressure isn’t going to be too strong. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [May 14, 2014, 3:12pm UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/3 "2014-05-14T15:12:46Z")
> [@Chronos](#): > > You have it correct. It’s basically mammals who are sensitive to it and birds who are not. I expect most other animals aren’t sensitive either, but most fructivores are birds and mammals. While there might be some evolutionary pressure on an animal to become desensitized, as long as there are plenty of other non-spicy food sources the pressure isn’t going to be too strong. Thanks. I had a pet parrot that used to love to eat hot peppers. Its incredible how the plant figured out and evolved to make themselves attractive to birds but unattractive to animals. ---
**Author:** ![Malthus](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Malthus](https://boards.straightdope.com/u/Malthus)\ **Post date:** [May 14, 2014, 4:02pm UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/4 "2014-05-14T16:02:44Z")
I bought some "squirrel-free’ birdseed that was based on this idea - it was supposed to be too hot for those pesky beasts to eat, but birds would like it just fine. All I can say is that I evidently have the world’s only “Tex-Mex appreciating” squirrels living in my backyard - they snarfed that shit down like it was going out of style, and asked for seconds. So far, the squirrels have outsmarted all of my attempts to feed birds and not them. ---
**Author:** ![leahcim](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@leahcim](https://boards.straightdope.com/u/leahcim)\ **Post date:** [May 14, 2014, 4:15pm UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/5 "2014-05-14T16:15:38Z")
> [@am77494](#): > > Its incredible how the plant figured out and evolved to make themselves attractive to birds but unattractive to animals. Their even bigger trick is finding the one stupid mammal species that can detect capsaicin but for some reason _doesn’t_ avoid it, and enslaving that species to not only spread their seeds, but to plant, fertilize, and irrigate them as well. Diabolical. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [May 14, 2014, 5:27pm UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/6 "2014-05-14T17:27:20Z")
> [@am77494](#): > > Its incredible how the plant figured out and evolved to make themselves attractive to birds but unattractive to animals. Indeed. OTOH, it’s easy to understand why a mutation that caused a plant to produce a chemical like capsaicin would confer an evolutionary advantage, thus causing such a plant’s DNA to be disproportionately represented in succeeding generations. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 14, 2014, 7:11pm UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/7 "2014-05-14T19:11:29Z")
> [@](#): > > Quoth **am77494** : > > Its incredible how the plant figured out and evolved to make themselves attractive to birds but unattractive to animals. That’s not the only way. Blackberries and their relatives pull off the same effect using thorns. Perch on top with scrawny little legs and poke a small beak at the berries, and you’ll probably get out without a scratch. Try to poke in a whole huge big muzzle attached to an even bigger body standing on the ground, and you won’t be so lucky. ---
**Author:** ![dstarfire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dstarfire/32/5762_2.png) [@dstarfire](https://boards.straightdope.com/u/dstarfire)\ **Post date:** [May 15, 2014, 6:56am UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/8 "2014-05-15T06:56:40Z")
> [@Xema](#): > > Indeed. > > OTOH, it’s easy to understand why a mutation that caused a plant to produce a chemical like capsaicin would confer an evolutionary advantage, thus causing such a plant’s DNA to be disproportionately represented in succeeding generations. _shrug_ You say tomato, I say solanum lycopersicum. ---
**Author:** ![Peter\_Morris](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/peter_morris/32/359_2.png) [@Peter\_Morris](https://boards.straightdope.com/u/Peter_Morris)\ **Post date:** [May 15, 2014, 7:07am UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/9 "2014-05-15T07:07:01Z")
You know, I actually heard it was the other way around. Birds have very few taste buds, and everything is bland to them. But they like eating chillies because its something they actually CAN taste. So, that’s wrong then? Or maybe true of some birds? ---
**Author:** ![kaltkalt](https://avatars.discourse-cdn.com/v4/letter/k/bb73d2/32.png) [@kaltkalt](https://boards.straightdope.com/u/kaltkalt)\ **Post date:** [May 15, 2014, 8:31am UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/10 "2014-05-15T08:31:18Z")
What I don’t understand is how a lot of capsaicin can cause physical harm if all it does is immitate the sense of ‘heat’. Eat one of those bhut juloka peppers (or whatever they’re called) and you can get all sorts of physical problems aside from a red face. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [May 15, 2014, 8:59am UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/11 "2014-05-15T08:59:51Z")
> [@kaltkalt](#): > > Eat one of those bhut juloka peppers (or whatever they’re called) and you can get all sorts of physical problems aside from a red face. A physical problem for the animal. But from the plant’s point of view, its seeds have been distributed and fertilized. ---
**Author:** ![kaltkalt](https://avatars.discourse-cdn.com/v4/letter/k/bb73d2/32.png) [@kaltkalt](https://boards.straightdope.com/u/kaltkalt)\ **Post date:** [May 15, 2014, 9:47am UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/12 "2014-05-15T09:47:25Z")
Yea i get that. I’m wondering why the fake sensation of heat in the animal (as opposed to an actual fire) causes physical problems. And I don’t just mean choking. You can get actual chemical burns from pure capsaicin can’t you? Just rubbing it on your skin. And indigestion, hearthburn, etc. All from the fake sensation of heat. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [May 15, 2014, 10:43am UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/13 "2014-05-15T10:43:47Z")
The sensation of heat might be fake, but the stuff is genuinely chemically interacting with your taste buds and mucus membranes. The heat is fake, the irritation is real. ---
**Author:** ![kaltkalt](https://avatars.discourse-cdn.com/v4/letter/k/bb73d2/32.png) [@kaltkalt](https://boards.straightdope.com/u/kaltkalt)\ **Post date:** [May 15, 2014, 11:10am UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/14 "2014-05-15T11:10:42Z")
it’s interacting like any other chemical that touches my tongue/taste buds. The flavors of a banana are chemicals causing a chemical reaction. That alone doesn’t explain it. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [May 15, 2014, 12:12pm UTC](https://boards.straightdope.com/t/capsaicin-and-evolution/688438/15 "2014-05-15T12:12:13Z")
Salt can damage tissue as well in high enough concentrations, even though we need a little bit of it to survive. Some chemicals are more irritating than others, and capsaicin is one of those that in high amounts is damaging.