I wonder what Sir David Attenborough would say on this subject. but I digress…
In his book, “Intoxication: Life in Pursuit of Artificial Paradise”, Richard Siegel suggests that people in hunter-gatherer or early agricultural societies would watch what their animals ate and how they behaved following ingestion. They would then follow up by ingesting the plant material themselves to experience the same sensations.
Early in his book, Siegel describes the exhilaration he felt when he discovered a pottery shard showing a native observing a llama chewing a wad of coca, reaching out to a coca plant to put some in his mouth.
The morning after Siegel discovered the pottery shard, he prepared for the long trip back to his hotel in Lima, and pushed a large wad of coca leaves. The coca “blew like a fresh wind through my tired body.”
It’s interesting that he should use those words in describing his rush of cocaine. Years earlier, Bill Wilson, co-founder of Alcoholics Anonymous, described his discovery of turning to the Father of Light to attain sobriety: “I felt lifted up, as though the great clean wind of a mountain top blew through and through.”
Siegel then describes numerous instances of mammals and birds grazing on vegetation or ingesting berries which induce clear signs of impairment, if not intoxication. Birds fall out of the sky, horses hit their heads against trees, and cows have difficulty walking straight, depending on the alkaloid that they ingested. If Müllerian mimicry were the only principle at work, then these herbivores would learn to avoid these noxious herbs. However, Siegel observes animals repeatedly returning to the same shrubs, grasses and trees, even when more nutritious food sources are available, presumably to repeat the intoxicating experience.
So, with that as an introduction, let’s take a look at some of the drugs which animals actually seek:
I. Caffeine
A. Mode of Action
Caffeine is an effective psychostimulant, ingested to “obtain a rewarding effect usually described as feeling more alert and competent.” It acts by inhibiting the binding of adenosine in the brain, which is an integral part of the onset of sleep. The blockade of adenosine receptors by caffeine stimulates activity of neurotransmitters such as dopamine and acetylcholine. The alertness which comes from the use of caffeine is a behavioral reinforcer. The cerebral cortex is affected first, with increased mental alertness, a faster and clearer flow of thought, and wakefulness. Fatigue is reduced and the need for sleep is delayed. Although increased mental awareness may result in sustained intellectual effort, tasks that require delicate muscular coordination and accurate timing or arithmetic skills may be impaired.
B. The evidence. By the way, these videos surprised me, too:
https://www.youtube.com/shorts/3z8jCLCg8Ps
II. Alcohol (Ethanol)
A. Model of action
Ethanol has three major effects:
- Ethanol binds to GABA receptors, thereby causing negatively-charged chloride ions to enter the neuron. This additional negative charge entering the charge makes the neuron less likely, thus quieting neuronal activity.
- Ethanol inhibits release of acetylcholine. Since intact cholinergic mechanisms are necessary for learning and memory, this anticholinergic action may contribute to alcohol’s impairment of cognition. Such anticholinergic action is probably indirect, occurring secondary to increased GABA inhibition of acetylcholine.
- Ethanol also augments the reward circuitry of the brain, i.e., the dopamine neurotransmitter system, starting from the ventral tegmental area (VTA) where it increases the firing rate, to the nucleus accumbens and to the frontal cortex.
B. Examples. Lots of them:
III. Cocaine
A. Mode of action
The primary mechanism of action of cocaine is by blocking the reuptake of the neurotransmitters dopamine, norepinephrine, and serotonin in the brain and peripheral nervous system. This leads to an accumulation of these chemicals in the synaptic cleft, which causes the stimulating and euphoric effects of the drug.
- Dopamine: This is the most significant interaction for cocaine’s addictive potential and its rewarding effects. By blocking the dopamine transporter (DAT), cocaine causes a massive buildup of dopamine in the brain’s reward circuit (the mesolimbic system), particularly the nucleus accumbens. This surge in dopamine creates intense feelings of pleasure and euphoria, reinforcing the desire to use the drug again.
- Norepinephrine and Serotonin: Cocaine also blocks the reuptake of norepinephrine (noradrenaline) and serotonin. The increase in norepinephrine contributes to the drug’s stimulant, or sympathomimetic, effects, such as increased heart rate, blood pressure, and alertness. The increase in serotonin affects mood, appetite, and sleep.
B. What happens when people trying to smuggle in bricks of cocaine realize that federal agents are closing in on them? They dump the bricks into the water…where SHARKS get them:
IV. Fly agaric mushrooms (muscimol)
A. Mode of action
Like ethanol, muscimol binds to the same active site on the GABA-A receptor complex, thereby causing a flow of negatively charged chloride ions (
Physiological Effects
The widespread inhibition of the central nervous system by muscimol leads to its characteristic depressant and psychoactive effects, which can include:
- Sedation and drowsiness
- Muscle relaxation and loss of coordination (ataxia)
- Altered sensory perception, confusion, and vivid, dream-like hallucinations (delirium)
- In severe cases, respiratory depression, coma, and seizures, although fatalities are rare with medical support.
B. The prime example involves shamans and reindeer in Siberia:
The author of https://www.iflscience.com/do-animals-use-drugs-wild-39623 relates that the story of “Rudolph the red-nosed reindeer and his flying herd-mates originates in Siberia, where the highly hallucinogenic fly agaric mushroom grows in abundance. Containing the hallucinogenic compound muscimol, the red and white speckled toadstool can be toxic to humans, but is safely metabolized by reindeer. The animals have often been seen acting high after ingesting the shrooms, giving birth to the notion of Santa’s flying reindeer.”
Siegel, R.K. (1989). Intoxication: Life in Pursuit of Artificial Paradise
. E. P. Dutton, New York.
Addictions and Recovery 