Apr 13, 20235 min read

Do Ants Feel Pain? The Truth About Ants and Their Sensitivity to Pain

Ants are fascinating creatures that have captured the attention of scientists and nature enthusiasts alike. But have you ever wondered, do ants feel pain?

All of us have grown up laughing at the jokes about the ant and the elephant.

Do you know the story where an ant and an elephant were riding in a car when suddenly, they met with an accident.

The elephant died but the ant survived.

How?

The ant was wearing a helmet

Now, have you wondered why did the ant bother to wear a helmet?

Are ants scared of fatal injuries?

Do ants feel pain?

Do ants try to keep themselves safe from harmful injuries?

Believe it or not, the answer is yes! Despite their small size and simple nervous system, ants are quite adept at sensing and avoiding painful stimuli.

When they encounter something dangerous, they release chemicals and pheromones that signal to their fellow ants to steer clear. It's not quite the same as the complex experience of suffering that we humans can feel, but it's a remarkable survival mechanism nonetheless.

How Do Ants Feel Pain?

Around a decade ago, researchers discovered that ants feel critical pain, defined as “nociception”.

What Is Nociception?

Nociception denotes the central nervous system (CNS) and peripheral nervous system (PNS) handling harmful stimuli, for example, accidental tissue injury and extreme temperature, which lead to the activation of nociceptors and their respective pathways.

Nociception triggers certain physiological and behavioral responses due to harmful stimulation like chemical burning, bruising pressure, sharp cutting or unbearably high environmental conditions.

‘Pain’ as an emotion is absolutely a subjective experience an insect feels as an outcome of the stimulation of these pathways.

To determine - ‘Do ants feel pain?’, researchers carried out an experiment where they damaged a leg of an ant-like insect, a fruit fly, Drosophila. This act results in the feeling of a chronic painful sensation in the insect’s nervous system.

The insect was then allowed to heal. The insects were placed in a room with high temperatures to record their response to extreme temperatures. It was observed that the insects were trying to leave the room to avoid the heated environment.

The flies were described to have become ‘hypersensitive’ to stimuli.

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Exploring the Evidence: Do Ants Feel Pain?

Greg Neely of the University of Sydney answered by pointing out that after an animal has been chronic, they activate a defense mechanism that makes them hypersensitive to external stimuli to protect itself from another harmful injury.

The instinct or feeling that makes the insect aware of a chronic injury leading to the activation of hypersensitivity can be collectively termed as ‘pain’.

By digging down to the genomic level, research was carried out to further explain this kind of sensitization. It turned out that the sensory neurons and a ventral nerve cord were involved.

The inhibitory neurons acted as the gatekeepers by allowing the signals of pain to navigate throughout the insect’s body. Any kind of fatal injury changes the threshold (the minimum requirement) of painful sensitization, thereby, making the insect hypersensitive to harmful stimuli. This process is called central disinhibition.

Central disinhibition causes the breaking off of the ‘pain brake’ mechanism of the insect’s nervous system. The pain-brake mechanism is responsible for soothing the perception of pain and hence, prevents hypersensitivity.

Ants also possess a nervous system composed of a group of ganglia that similarly navigate the signals of pain.

Ants Lack Nociceptors:

The specialized sensory neurons are responsible for detecting harmful stimuli and are called nociceptors. These nociceptors induce rapid escape or withdrawal on sensing harmful stimuli.

The ganglia run through the head, thorax and abdomen. The workers of the ant colony have a smaller number of vision neurons causing dull eyesight. Ants have a huge number of neurons for learning and olfactory functions through their antennae.

Pain, as said earlier, is an absolutely subjective experience that includes the navigation of negative emotions. Though the term is the same, ants feel it in a different way. But this doesn’t mean that their pain is chemically non-existent.

The limited cognitive abilities of ants have highly reduced their ability to detect the kind of pain humans or other higher vertebrates feel on being harmed.

Some scientists have observed that the pheromones of ants also have a significant role to play in initiating sensitive reactions to injuries in the body of an ant. Research is still going on regarding this issue, so the role of pheromones is still cloudy here.

Ants release chemicals or pheromones which create signals indicating risks of death or injury, thereby, ants feel slight distress or irritation when harmful life-threatening conditions exist.

Interestingly Ants may also Die Due to a Lack of Nutrition:

So, the suffering connected to pain that is inexperienced by higher vertebrates is highly reduced in ants to a danger signal. The death of an ant releases a signal(basically a pheromone) for its mates to either bury the body or take precautions to save themselves from the danger which had killed their mate.

Ants cannot even feel the pain of poisoning by insecticides. The presence of only 2,50,000 nerves in their brain is unable to detect the poisoning occurring in their internal organs.

Gibbons and his colleagues discovered that insects lack the genes for the opioid receptors that are responsible for down-regulating pain in humans.

But, insects do produce certain proteins during life-threatening situations which serve a similar function. Molecular pathways for suppressing responses also work in some insects.

For example, behavioral studies indicated that the presence of a sugar solution leads to the suppression of a bumblebee’s normal avoidant response to harmful stimuli.

Mitigation behaviors have also been observed in tobacco hornworms on receiving a fatal injury.

Parting Note:

While some people still believe that ants do not feel pain, many scientific researchers say otherwise. While the question of whether ants feel pain is still up for debate, one thing is clear - these tiny creatures are more complex than we ever imagined.

So, the next time you see an ant scurrying along your desk or enjoying a cube of sugar then you may think twice before killing it or squishing it. Though an ant may not experience any kind of suffering, still an irritable reaction ensues from its nervous system.

Instead of killing an ant, you may try to swipe it away by blowing a gush of air from your mouth.

In case you step on an ant, you may not need to feel deep guilt since now you know that the ant did not experience any suffering, but just a triggering chemical reaction or the activation of a hypersensitive defense mechanism.

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