# What's the most primitive species to have the Fight-or-Flight response? **URL:** \ **Category:** Factual Questions\ **Created:** [August 18, 2022, 3:40pm UTC](https://boards.straightdope.com/t/whats-the-most-primitive-species-to-have-the-fight-or-flight-response/969896 "2022-08-18T15:40:16Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [August 18, 2022, 3:40pm UTC](https://boards.straightdope.com/t/whats-the-most-primitive-species-to-have-the-fight-or-flight-response/969896/1 "2022-08-18T15:40:16Z")
The fight or flight response is described as : > **[Fight-or-flight response](https://en.wikipedia.org/wiki/Fight-or-flight_response)** > > The fight-or-flight or the fight-flight-or-freeze response (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. It was first described by Walter Bradford Cannon.\[a\] His theory states that animals react to threats with a general discharge of the sympathetic nervous system, preparing the animal for fighting or fleeing. More specifically, the adrenal medulla produces a hormona This res... Wondering how prehistoric is this response in life forms ? Since plants do not move or take “flight” do they have an equivalent response ? Whats the earliest known lifeform to have this response ? ---
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [August 18, 2022, 4:31pm UTC](https://boards.straightdope.com/t/whats-the-most-primitive-species-to-have-the-fight-or-flight-response/969896/2 "2022-08-18T16:31:12Z")
If you poke an amoeba, it will move away from you… but I don’t think that’s what you were looking for. Are you talking about primitive animals with a brain and a nervous system? ---
**Author:** ![Buck\_Godot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/buck_godot/32/6573_2.png) [@Buck\_Godot](https://boards.straightdope.com/u/Buck_Godot)\ **Post date:** [August 18, 2022, 5:09pm UTC](https://boards.straightdope.com/t/whats-the-most-primitive-species-to-have-the-fight-or-flight-response/969896/3 "2022-08-18T17:09:00Z")
Although it may not be what the OP is looking for, I think it illuminates the answer. Moving away from danger is such a strongly adaptive survival strategy that any creature that it would be incorporated at all levels of evolution. So if the Amoeba doesn’t count, the answer would be the first creature that has enough biological architecture to fit their definition. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [August 18, 2022, 6:20pm UTC](https://boards.straightdope.com/t/whats-the-most-primitive-species-to-have-the-fight-or-flight-response/969896/4 "2022-08-18T18:20:42Z")
> [@dolphinboy](#): > > Are you talking about primitive animals with a brain and a nervous system? No the presence of a brain and nervous system is not necessary. I am trying to understand if the earliest life (some say it was microbes that left signals of their presence 3.7 billion years back ) or the cyanobacteria that came later had the “fight or flight response” > [@Buck\_Godot](#): > > So if the Amoeba doesn’t count, the answer would be the first creature that has enough biological architecture to fit their definition. Thank you. Exactly!! I am trying to answer : If any or all entities that were (or are) alive or sentient have the “fight or flight response” ? ---
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [August 18, 2022, 6:30pm UTC](https://boards.straightdope.com/t/whats-the-most-primitive-species-to-have-the-fight-or-flight-response/969896/5 "2022-08-18T18:30:06Z")
I’m unsure what evidence there would be to prove whether a creature did or didn’t have a fight-or-flight response. It’s an automatic response to a threat. Perhaps the fact that a family of creatures has survived the longest would let you assume they must have had this response, or they wouldn’t have survived. So based on that theory, I would go with the Horseshoe Crab since most scientists agree it is the oldest living species still around today. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [August 18, 2022, 7:23pm UTC](https://boards.straightdope.com/t/whats-the-most-primitive-species-to-have-the-fight-or-flight-response/969896/6 "2022-08-18T19:23:47Z")
> [@dolphinboy](#): > > It’s an automatic response to a threat. The question is if “organisms”/“lifeforms” had this “automatic response” from the very beginning. Or did organisms evolve this response over time. I am not sure about what evidence we’d have. I guess, we’ll never know. ---
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [August 18, 2022, 7:28pm UTC](https://boards.straightdope.com/t/whats-the-most-primitive-species-to-have-the-fight-or-flight-response/969896/7 "2022-08-18T19:28:01Z")
Perhaps if you were an Apex Predator, you wouldn’t need to evolve it, but what animal started as an Apex Predator? ---
**Author:** ![Buck\_Godot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/buck_godot/32/6573_2.png) [@Buck\_Godot](https://boards.straightdope.com/u/Buck_Godot)\ **Post date:** [August 18, 2022, 8:11pm UTC](https://boards.straightdope.com/t/whats-the-most-primitive-species-to-have-the-fight-or-flight-response/969896/8 "2022-08-18T20:11:05Z")
It looks like the first mobile organisms were at least 2.1 billion years old. > **[Earth’s Earliest Mobile Organism Lived 2.1 Billion Years Ago](https://learningenglish.voanews.com/a/earth-s-earliest-mobile-organism-lived-2-1-billion-years-ago/4784826.html)** > > Scientists have discovered the oldest fossil evidence of the organism motility, the ability to move independently. The discovery shows that development of motility began more than two billion years ago. Of course no one can know whether that movement included a move away from danger reflex, or if it was just a move towards food reflex, but I suspect that the move away from danger evolved pretty quickly. Beyond that I think its likely to be a continuum of adaptive strategies to avoid danger, with no clear place to draw a line and say “this is fight or flight”. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [August 18, 2022, 8:11pm UTC](https://boards.straightdope.com/t/whats-the-most-primitive-species-to-have-the-fight-or-flight-response/969896/9 "2022-08-18T20:11:56Z")
How about aiptasia, AKA glass anemone? They will curl up it touched, will eat very small creatures like brine shrimp, and sting coral that are too close. > **[Aiptasia](https://en.wikipedia.org/wiki/Aiptasia)** > > Aiptasia is a genus of a symbiotic cnidarian belonging to the class Anthozoa (sea anemones, corals). Aiptasia is a widely distributed genus of temperate and tropical sea anemones of benthic lifestyle typically found living on mangrove roots and hard substrates. These anemones, as well as many other cnidarian species, often contain symbiotic dinoflagellate unicellular algae of the genus Symbiodinium living inside nutritive cells. The symbionts provide food mainly in the form of lipids and sugars... ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [August 19, 2022, 12:59pm UTC](https://boards.straightdope.com/t/whats-the-most-primitive-species-to-have-the-fight-or-flight-response/969896/10 "2022-08-19T12:59:45Z")
> [@am77494](#): > > Since plants do not move or take “flight” do they have an equivalent response ? Depends on your standard for “equivalent”… > **[Thigmonasty](https://en.wikipedia.org/wiki/Thigmonasty)** > > In biology, thigmonasty or seismonasty is the nastic (non-directional) response of a plant or fungus to touch or vibration. Conspicuous examples of thigmonasty include many species in the leguminous subfamily Mimosoideae, active carnivorous plants such as Dionaea and a wide range of pollination mechanisms. > Thigmonasty differs from thigmotropism in that nastic motion is independent of the direction of the stimulus. For example, tendrils from a climbing plant are thigmotropic because they twine ar... [![](https://upload.wikimedia.org/wikipedia/commons/f/fe/Mimosa_Pudica.gif) ](https://upload.wikimedia.org/wikipedia/commons/f/fe/Mimosa_Pudica.gif) ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [August 19, 2022, 1:18pm UTC](https://boards.straightdope.com/t/whats-the-most-primitive-species-to-have-the-fight-or-flight-response/969896/11 "2022-08-19T13:18:36Z")
It might be more interesting to consider what animals exhibit any of the three “fight, flight, freeze” responses. For example, I know rodents will do any of the three, depending on the situation. I suspect all mammals will also. (Can anyone think of a counter example?) Are there older clades that have all exhibit all three responses?