In reality, this question does not have a specific answer, as evolution is a random process and we cannot actively choose our natural evolutionary path. We all know that in the wild, many animal species have evolved and possess incredibly potent toxins.
For example, the average lethal dose of venom from the inland taipan snake is 0.025 mg/kg. Typically, an inland taipan can deliver between 125 mg and 400 mg of venom in a single bite, enough to kill 250,000 mice, 100 adult humans, or two African elephants. In addition to amphibians or reptiles, mammals can also be venomous. A notable example is the platypus, which has hollow spurs on its hind limbs that can deliver toxins.
In fact, it is more accurate to say that the primitive nature of the platypus has allowed it to evolve to possess venom. If we look closely and from a scientific perspective, we find that most highly venomous animal species tend to be small or relatively primitive. Small size or primitive evolution is certainly not what describes humans. Instead, we can observe that larger and more complexly evolved animals mostly rely on physical attacks and intelligence. Creatures tend to abandon venom as they evolve, which may explain why mammals and birds have fewer venomous species.
The venom of the inland taipan snake is very dangerous.
The venom of the inland taipan snake is indeed very dangerous; the venom from each bite can kill 100 people or 2 African elephants. However, this is merely a calculation, as there are very few chances for this snake species to encounter humans.
Why is that? The main reason is toxin resistance; many species in the natural world can easily develop a 100% resistance to toxins, whereas resistance to physical attacks is not as effective.
A prime example of this is the African honey badger.
The honey badger is one of the animals capable of resisting toxins.
Honey badgers are known for their fearless attitude; if they want to do something, they will make every effort to achieve it. Despite their relatively modest size, they can consume a 1.5-meter-long cobra in just a few minutes. However, when honey badgers attack cobras, they often get bitten. Typically, these bites do not have an immediate effect; usually, after attacking and eating half of the snake, they will faint. But no worries, after a few hours, the snake venom will break down in their bodies, and they can wake up to finish the rest of the snake.
So how does toxin resistance work? Cobra venom has two main functions: one is to kill the victim quickly, and the other is to break down the victim’s cells. Thus, the focus of venom resistance primarily targets these two criteria, counteracting the initial lethal strike and eliminating residual toxins.
Snake venom consists of protein segments known as polypeptides. In the case of the king cobra, the rapidly lethal component in its venom is the alpha neurotoxin. The function of alpha-neurotoxin is to bind to nicotinic acetylcholine receptors, preventing them from generating electrical signals, thereby paralyzing the muscles, causing respiratory and cardiac failure, leading to death.
Meanwhile, the honey badger has a unique mutation in its DNA that makes its acetylcholine receptors smaller, making it difficult for the alpha neurotoxin in the cobra’s venom to bind and exert its effects. To visualize this, it is like a large SUV trying to fit in an elevator. Although there is still some inhibitory effect, it is significantly reduced, insufficient to pose a life-threatening danger.
The second criterion is to eliminate residual toxins, which is the function of the immune system. Theoretically, humans can also detoxify by producing antibodies that bind to polypeptide molecules to inactivate them. However, most of us have very little exposure to snakes, and few people have been bitten. Therefore, our immune memory regarding snake venom is entirely empty, meaning after a snake attack, the body doesn’t have time to produce antibodies before the cells are destroyed.
It can be seen that resisting snake venom is not particularly difficult. If large mammals lived in environments with regular exposure and had to counteract snake venom, they could potentially evolve the ability to “develop resistance.” In fact, there are four animal species in nature known to resist snake venom: the honey badger, the suricate (Suricata suricatta), the hedgehog (Erinaceinae), and wild boars (depending on their geographical distribution), all of which share a similar mutation in their acetylcholine receptor genes.
A venomous cobra can kill 20 people but not harm a wild boar, demonstrating that this is not an extraordinary skill.
On the other hand, what about physical attacks? Essentially, there are no particularly effective defensive methods against physical attacks; even huge turtles with very hard shells can be bitten by sharks. Strength, speed, and agility are the pathways of evolution in terms of competitive biological capability.
Moreover, another fact is that tiny venomous creatures have never dominated the food chain, and the highly venomous golden poison dart frog still has natural enemies. Initially, toxins did not originate from animals. The true owners of toxins in nature are plants. Conceptually, all plant species are toxic, but not all affect every animal species, such as the toxins in cocoa and coffee beans. These components can be toxic to dogs and cats but pose no danger to humans and goats.
