Do plants feel pain? Do they have feelings?
As you process these questions, you probably have a natural assumption that plants do or do not feel pain.
Whatever your stance, it may seem pretty straightforward. As it turns out, the answer to this question can be complex.
If you’re vegan, you probably cringe every time someone tells you, “but, plants have feelings too”. Or ask, “if you care about killing animals, why don’t you care about killing plants?”
Then you non-confidently mumble back a response about how plants don’t have a central nervous system so scientifically, they can’t feel pain.
While this statement is somewhat true, there’s more to consider about the sentience of plants.
I get the intent behind the questions. If plants have feelings and can experience pain, then what’s the difference between eating animals and plants? Why is there a hierarchy of suffering?
This post is my attempt to present arguments for and against the “plants have feelings too” debate, before weighing in on my own opinion towards the end.
Let’s get into it.
What’s pain, and how does it work?
To understand if plants feel pain, we must first define what pain is.
A quick Google search reveals that pain is a highly unpleasant physical sensation caused by illness or injury.
Okay, that seems pretty obvious. Let’s get a little more specific.
Animals (human and non-human) perceive pain through sensory nerve cells. The same network of cells that process our sight, touch, smell, hearing and taste.
As explained in the textbook Pain and Disability: Clinical, Behavioral, and Public Policy Perspectives, pain receptors which are present in most body tissues, respond to damaging or potentially damaging stimuli.
Messages initiated by this stimuli are transmitted by nerve cells to the spinal cord and the brain (your central nervous system). If the brain perceives the threat to be legitimate, it responds by creating a sensation of pain to direct attention to the body part so that the danger can be mitigated.
It’s like if you were to hit your big toe on the bottom of your bed frame. The impact of the connection creates stimuli. From there the nerve cells get sent to your brain, which the brain approves and creates the sensation of pain to your big toe.
With this information, you analyse the risk of further pain by avoiding repeated action. Additionally, your brain signals to not to put pressure on your toe to give it time to heal.
We must also remember that pain is a subjective emotion, not just a physical response. This is why animals can experience complex pain-related emotions like fear, sadness and anger.
For example, a cow can experience trauma from being separated from her calf after birth, much like how a human mother could experience the same emotional pain in the same situation.
To summarise, pain is the process of turning stimuli into a subjective emotional experience to mitigate future risk and promote healing.
What’s a plant?
Plants are living organisms that come in many different forms. We’ve come to know them as trees, shrubs, herbs, grasses, ferns, and mosses.
There are three basic structures of a plant:
- Leaf – the leaf is an organ of a plant that captures energy from sunlight. Leaves also collect carbon dioxide from the air.
- Stem – the stem is the core structure of a plant that supports leaves, branches and flowers. Stems have vascular tissues that move food and water around the plant to help it thrive and grow. Plants often store food in stems.
- Roots – the roots of a plant grow underground and help the plant stay balanced while also gathering minerals and water from the soil. Some plants store food in their roots.
There are almost 400,000 plant species, and scientists are discovering more each day.
To put it simply, plants rule the world—representing 80 per cent of the earth’s biomass.
Personally, I love plants as we owe our existence to them.
They provide food, shelter, shade, clean air and beauty. Plants, in many ways, represent life.
It’s essential to acknowledge the overwhelming significance of plants as we consider the emotions of this infinitely generous species.
A case for why plants feel pain and have emotion
In this next section, I break down three case studies that are regularly referenced when making an argument that plants feel pain.
Where possible, I’ve linked to the papers for your perusal.
1. Plants can hear themselves being eaten by caterpillars
In a paper published in 2014 titled Plants respond to leaf vibrations caused by insect herbivore chewing, researchers found plants increased their chemical response to the vibrations caused by a caterpillar chewing.
The study involved placing caterpillars on plants called Arabidopsis, then using lasers and reflective materials to measure the movement of the leaf in response to the caterpillar munching.
The recordings of the caterpillars feeding vibrations were played back to a set of plants and played silence to another set of plants.
It was found that the plants that had been forced to listen to the sound of the vibrations from the munching produced more mustard oils, which are chemicals insects don’t like.
The argument here is that plants respond to pain by producing defence mechanisms when they detect a threat.
2. Plants can communicate with each other
In a paper published in 1983 titled Rapid Changes in Tree Leaf Chemistry Induced by Damage: Evidence for Communication Between Plants, researchers found signs of communication amongst maple trees as a response to intentionally cutting their leaves.
Specifically, increased rates of synthesis and phenolic compounds were found amongst a group of maple seedlings 52 hours after having 7 per cent of their leaf area removed from tearing.
The argument here is that plants can release chemicals as a form of communication to warn other plants of the threat, as a reaction to pain.
This paper was met with a lot of controversies as early studies could not be replicated.
Then another paper published in 2014 titled Volatile communication between plants that affects herbivory: a meta-analysis, stating that they found 48 well-replicated studies since the 1983 research. Through their meta-analysis, they found overall support for the hypothesis that resistance increased for individuals with damaged neighbours.
But like most research, they stated in the conclusion that more testing is required for consistency of results, and adjusted for environmental variables. For example, all of the studies reviewed so far occurred in a lab, not in nature, which may be a factor when analysing the communication between plants.
The other question mark in the testing is the lack of reciprocation in communication between the plant subjects. It appears that when herbivores attack a plant, the plant emits communications to others, but there’s no evidence of the other plants communicating to the emitter.
This suggests that the response of the emitter is more of a message or broadcast of warning, as opposed to a cry for help.
3. Plants are reportedly “screaming” when under stress
In a paper published in December 2019 titled Plants emit informative airborne sounds under stress, researchers found that plants emit high-pitched sounds when threatened.
Specifically, they recorded the sound waves over some time for tomato and tobacco plants when dry, cut, and normal.
The results showed that when the plant was under stress, e.g. dry or cut, they found the plants began to emit ultrasonic sounds between 20 and 100 kilohertz.
Plants emit sounds that humans can’t hear (without assistance), so the researchers used ultrasonic microphones to detect the sound waves in the study.
Keep in mind that this paper is not peer-reviewed at the time of publishing this post.
But the results do raise an interesting element to the “plants have feelings” debate.
If plants are, in fact, screaming when under stress, we can make some assumptions that they do at least react to pain.
A case for why plants don’t feel pain and have emotions
Whether it’s reacting to vibrations, sending warning signals, or literally screaming, we still have much to learn about plants.
These examples together are put forward a compelling case for plants being able to experience pain.
Having said that, the argument for why plants don’t feel pain or emotions doesn’t need much explaining. It all comes down to biology.
As explained earlier in this post, pain is an experience that incorporates communication between stimuli, receptors, cells, and the central nervous system.
It’s one thing to merely react to a threat, and it’s another thing to intellectualise it.
Animals suffer from pain because they consciously process pain. It’s the brain and spinal cords which make us aware of the pain, again, which is a subjective response based on complex emotions.
The examples of plants releasing chemicals and sounds without the processing from a central nervous system can be considered to be a basic stimulus-response.
It’s similar to how plants react to stimulus from the sun, water, or soil.
These responses draw comparisons to technology. For instance, when you press the button on a doorbell, it responds by making a noise.
Or when the battery on your phone gets low, it responds by flashing.
These are responses, not intellectually processed emotions.
The famous Venus flytrap plant
Another example that is perhaps more relevant than technology is the well-known plant, Venus flytrap.
Venus flytrap is a carnivorous plant that eats insects, frogs and human flesh if given the opportunity.
This unusual plant lures in prey by using sweet scent from its nectar. Once the prey is at the jaws of the Venus flytrap, the plant gets ready to snap shut.
Professors from the University of Tasmania have said that Venus flytraps don’t recognise animals; they respond to mechanical stimulation.
This is further proven by the Venus flytrap responding to a cigarette placed in its jaws.
Carnivorous Plant Smoking a CIGARETTE (捕蠅草)
If the plant had a central nervous system, it would be able to consciously discern its prey to consume the most optimal nutrients for its biology.
You can’t just give any animal a rock to eat—they would consciously process potential food using their sensory cells and their brain. It’s the same system used to process fear, sadness and suffering.
My final thoughts on whether plants have feelings
There’s no question that we’re learning more about plants every year, and the research about how they respond to stimuli is fascinating.
But even after reading the research, I couldn’t see any clear peer-reviewed evidence of plants showing anything beyond mechanical response to stimuli.
The examples of plants responding to cuts, munching on leaves and drought seem obvious to me. Plants also react to music, quality soil, surrounding objects and sunshine.
Does it mean that they’re consciously responding to these situations? I think not.
Now, are plants living organisms? Absolutely, and humans generally treat them that way. We often refer to a plant as happy, sad, dead or alive.
But the absence of a brain limits a plants ability to take stimuli and process a conscious subjective response. Well, as far as we know.
So while I can’t definitively say that plants don’t have feelings, I’ve seen more evidence that they don’t.
For me, the deal-breaker is the difference between a mechanical response and a conscious response.
I’d love to hear from you now. What do you think? Do plants have feelings?
What are your thoughts on mechanical and conscious responses to threats? Let me know in the comments below.
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FAQs
Do vegans plants have feelings too? ›
In short – no. Plants do not feel pain because they lack pain receptors, nerves, or a brain which means they can't have feelings or feel pain the same way animals or humans do.
What is the vegan argument against plants feel pain? ›Plants are different to animals. Plants aren't sentient - they have no brain, no nerves, no central nervous system, and they have no ability to feel 'pain' or react in a conscious way. Plants can react to vibrations and chemical stimulus, but this isn't a conscious act, it's autonomic.
Can plants feel pain vegan? ›No, plants cannot feel pain. There is no possible way for that to happen without a central nervous system.
Do plants have emotional feelings? ›And since plants do not have brains, nor a central nervous system (which is how intelligence is defined), it is said to be impossible for them to have emotions and the ability to reason or feel.
Do plants know they are alive? ›Mountains of research have confirmed that plants have intelligence and even beyond that consciousness by many of the same measures as we do. Not only do they feel pain, but plants also perceive and interact with their environment in sophisticated ways.
Do plants have a soul? ›The reason for this is that, despite the lack of any kind of cognition, plants have souls too, according to Aristotle's widely-accepted theory: trees and flowers nourish themselves, they grow, and propagate, and so they have what was usually called a vegetative soul.
Do plants know when they are being eaten? ›According to a new study from the University of Missouri, plants are able to sense when they are being eaten and utilize defense mechanisms in an attempt to prevent it from happening. Plants recognize the sound of herbivores feeding on their leaves, and then use their tissues to send our vibrations.
Do plants have a pain response? ›The simple answer is that, currently, no one is sure whether plants can feel pain. We do know that they can feel sensations. Studies show that plants can feel a touch as light as a caterpillar's footsteps. But pain, specifically, is a defense mechanism.
Do plants like being touched? ›Your plants really dislike when you touch them, apparently. A new study out of the La Trobe Institute for Agriculture and Food has found that most plants are extremely sensitive to touch, and even a light touch can significantly stunt their growth, reports Phys.org.
Can dogs be vegan? ›Dogs prefer meat, but a vegan or vegetarian diet is possible with the right supplements. For health and ethical reasons, many vegetarian and vegan humans choose to share their dietary preferences with their dogs. In general, dogs are omnivorous.
Do plants want to be eaten? ›
Most Plants Don't Want to Be Eaten
But plants can't run, and their ability to fight is limited to the use of chemical weapons in the form of toxins, inflammatory proteins, enzyme inhibitors (also known as antinutrients) and (sometimes) thorns.
Do Plants React to Human Voices? Here's the good news: plants do respond to the sound of your voice. In a study conducted by the Royal Horticultural Society, research demonstrated that plants did respond to human voices.
Do plants respond to kindness? ›While flowers and other members of the plant kingdom seem not to complain when we pinch their buds or step on them, they are fully aware of what's happening and rapidly respond to the way they're treated, scientists have discovered.
Do plants have thoughts? ›Plants don't have a central nervous system, so thought (as we normally define it) isn't possible. But plants can sense their environment, respond to insect attacks and are even capable of limited movement.
Do plants miss you? ›They will miss you breathing out. Carbon dioxide increases photosynthesis, therefore spurring plant growth. With less humans around during the day, the Co2 levels will have decreased.
What is the most intelligent plant? ›Orchids are sometimes called "the smartest plants in the world" because of their ingenious ability to trick insects and people into helping with their pollination and transport.
Can plants see you? ›Plants detect visible and invisible electromagnetic waves. Unlike plants, we can only detect visible electromagnetic waves. Although plants can see a much larger spectrum than we do, they don't see it in images.
Can plants cry? ›Does it look like your leaves are dripping water or “crying”? This process, called guttation, is completely normal — your plant isn't upset! We see many plant hobbyists ask why their plant is dripping water and if it's okay, or a signal that something isn't right.
Can plants sense human thoughts? ›Plants do not. Plants may exhibit reactions to stimuli, and we sometimes interpret these responses as defensive behavior, but we're really talking about successful adaptations to their environment. Plants have neither nervous systems nor neuro-transmitting pain receptors.
What the Bible says about plants? ›Genesis 1:29
29 Then God said, “I give you every seed-bearing plant on the face of the whole earth and every tree that has fruit with seed in it. They will be yours for food.
Is it food to talk to your plants? ›
There is no consistent scientific evidence that talking or singing to plants helps them grow better or produce more fruit.
Do plants know their owners? ›Do plants recognize their owners? According to researchers, plants can count, make decisions, recognise their relatives and even remember events. And while they may not have a brain, they can learn in a similar way to humans and animals, say scientists.
Can you communicate with plants? ›Plants don't have brains and are not capable of communicating in any form.
Do plants feel anger? ›Nor does it experience fear, anger, relief or sadness as it topples to the ground. Trees — and all plants, for that matter — feel nothing at all, because consciousness, emotions and cognition are hallmarks of animals alone, scientists recently reported in an opinion article.
Do plants get traumatized? ›Transplant Shock occurs when a plant is uprooted or placed in a new pot and shows distressed symptoms afterwards. Plant Shock is a more generalized term that happens when there is stress due to abrupt changes in environment like temperature changes, water stress, over fertilizing, or drastic changes in light.
Do plants enjoy music? ›For most plants playing classical or jazz music caused growth to increase, while harsher metal music induced stress. This may be because the vibrations of metal music are too intense for plants and stimulate cells a little too much. We think of this like massaging your plant with a song – they prefer a gentler touch.
Why shouldn't you touch plants at night? ›In addition, at night you may not be able to see dangerous, spiders, bugs, or snakes that make their home in trees. In addition, at night it is difficult to identify dangerous plants (e.g. poison ivy, poison oak, stinging nettle, etc.).
Can plants love humans? ›It's something that plant lovers have long suspected, but now Australian scientists have found evidence that plants really can feel when we're touching them.
Do plants go to sleep at night? ›Although plants do not sleep in the same way that humans do, they do have more and less active times and they have circadian rhythms—internal clocks that tell them when it is night and when it is day. And like many people, plants are less active at night. When the Sun comes up, however, they awake to the day.
Is breast feeding vegan? ›Breast milk is OK for ethical vegans
As we've already stated, breastfeeding is a choice that doesn't involve animal exploitation, even when including humans as part of the animal kingdom. Perhaps the most well-known authority on veganism, People for the Ethical Treatment of Animals (PETA), agrees.
Can dogs eat bananas? ›
In moderation, bananas are a great low-calorie treat for dogs. They're high in potassium, vitamins, biotin, fiber, and copper. They are low in cholesterol and sodium, but because of their high sugar content, bananas should be given as a treat, not part of your dog's main diet.
Can cats be vegan? ›The short answer is no, cats can't be vegetarian or vegan. Cats are obligate carnivores which means they need meat in their diet. With the rise in plant-based diets in the UK, many have started to consider altering their pet's diet too. This can be for numerous reasons, such as environment, health or ethical reasons.
Is eating plants not cruel? ›When you eat plants, you bring in variety, and the variety brings to life rich fauna that then enriches the flora. So, when you eat plants, you don't kill life, you do quite the opposite - you enable new life, more prosperous!
Does grass feel pain? ›Short answer: no. Plants have no brain or central nervous system, which means they can't feel anything.
Do trees feel pain when they are cut down? ›As explained by plant biologist Dr. Elizabeth Van Volkenburgh, all living organisms perceive and respond to painful touch, but plants do not perceive or “feel” pain the same way that animals do because they lack a nervous system and brain.
Do plants vibrate when you talk to them? ›Plants respond to the vibrations of nearby sound which turns on two key genes inside of them that influence their growth. Plants also increase photosynthesis production in response to carbon dioxide, which is a by-product of human speech.
Can plants feel your energy? ›Trees — and all plants, for that matter — feel nothing at all, because consciousness, emotions and cognition are hallmarks of animals alone, scientists recently reported in an opinion article.
Should I talk to my plants? ›The bottom line? "The best thing people can do to help their plants grow is provide them with light, water, and mineral nutrition," says Marini. While the studies suggest that sound may spur plants to faster growth, there is no definitive evidence that a gift of gab will turn you into a green thumb.
What plants don't like to be touched? ›The mimosa pudica — also known as the sleepy plant or touch-me-not — reacts dramatically when touched or shaken.
Do plants have dignity? ›Plants are living beings, so they also have dignity. The Executive Federal Council directed the Federal Ethics Committee on Non-Human Biotechnology (ECNH), of which I am a member, to work out the basis for these constitutional norms.
Do plants remember us? ›
Things happen to plants, and as far as I know, they go on as before. They don't have brains. They have no way to “remember” anything. They're not animals.
Do plants have memories? ›Like humans, plants have memories too, although they do it differently. For example, many plants sense and remember prolonged cold during winter to ensure that they flower in spring.
Do my plants know I love them? ›And since plants do not have brains, nor a central nervous system (which is how intelligence is defined), it is said to be impossible for them to have emotions and the ability to reason or feel.
Do plants feel pain when cut? ›Given that plants do not have pain receptors, nerves, or a brain, they do not feel pain as we members of the animal kingdom understand it. Uprooting a carrot or trimming a hedge is not a form of botanical torture, and you can bite into that apple without worry.
Do plants have feelings like animals? ›Short answer: no. Plants have no brain or central nervous system, which means they can't feel anything. But let's dive a bit deeper. Humans and animals perceive pain through sensory nerve cells.
Do plants like to be talked to? ›There are many studies that verify that plant growth is influenced by sound. Many found that at the average human conversational tone (70 decibels) there was increased production in plants. Not only will your plants benefit from your conversations but you may get a psychological boost as well.
Can trees see us? ›Don't look now, but that tree may be watching you. Several lines of recent research suggest that plants are capable of vision—and may even possess something akin to an eye, albeit a very simple one. The idea that plants may have “eyes” is, in a way, nothing new.
Do trees talk to each other? ›Trees share water and nutrients through the networks, and also use them to communicate. They send distress signals about drought and disease, for example, or insect attacks, and other trees alter their behavior when they receive these messages.” Scientists call these mycorrhizal networks.
Does grass feel pain when you cut it? ›Plants Feel Pain FAQ
While plants don't have any pain receptors, nerves or a brain, so they likely can't feel pain in the same way that humans do.
"Although people generally assume plants don't feel when they are being touched, this shows that they are actually very sensitive to it," said lead researcher Olivier Van Aken from the University of Western Australia.