Why do venomous animals live in warm climates

Why are the Most Venomous Species Found in the Warmest Places on Earth?

Have you ever wondered why the most venomous species are found in the warmest places on Earth? Take Australia for example. Depending on who you ask, it has all or nearly all of the ten most venomous snakes in the world, plus the funnel-web spider, the blue-ringed octopus, box jellyfish, paralysis tick, and stonefish. All these creatures, found in Australia, are the most lethal of their kind. Even the seemingly harmless platypus has an ankle spur, which in the male, secretes a venom that can kill a dog. In humans, it would merely cause excruciating pain.

Are More Venomous Species Really Found in Hot Places?

Before we delve into the reasons, it’s worth asking, is it true that more venomous species really live in hot places? A comparison of a map of global average temperatures with a map colored according to the number of venomous species in each country seems to confirm this. The country with the most venomous species is Mexico, followed closely by Brazil and then Australia. This seems to match up very well with the global average temperatures.

Understanding Venom Molecules

One hypothesis is that there’s something about the heat which enables the formation of these venom molecules. However, this idea was debunked by Professor Polyakov of Periodic Videos, who explained that a ten-degree centigrade change in temperature around room temperature will only double the rate of most chemical reactions and is unlikely to cause such a significant evolutionary difference.

So, what exactly are these venom molecules? In most species where the venom is delivered by fangs, it has evolved from saliva. In the funnel-web spider, for example, the lethal effect seems quite accidental. The actual reason that spiders have venom is to digest their prey. They inject the venom and it starts to liquefy whatever they’ve caught. Once it’s turned to liquid, all spiders live on soup.

What Happens When You Get Bitten by a Venomous Creature?

If you get bitten by a venomous creature, such as the world’s most venomous land snake, the inland taipan, the venom travels through the lymphatic system, not the veins or blood vessels. If it reaches your nervous system, it’ll shut down the signaling pathways that keep your heart beating and your lungs breathing, leading to suffocation. The recommended response is to stay very still and bandage up the limb that’s been bitten from the tip all the way back to your torso. The bandage needs to be tight enough to trap the venom within the lymphatic system, but not so tight as to cut off the blood flow to the limb. Once you’ve got it bandaged up, you need to find some anti-venom.

What is Anti-Venom?

Anti-venom is made by injecting a large organism like a horse with a dilute solution of the venom. The horse then produces antibodies for that venom which you can harvest and inject into yourself in case you get bitten. Making anti-venom is tough work. It would take seventy milkings of a funnel-web spider to get enough venom to make a single dose of anti-venom. Moreover, anti-venom can only be used on an individual a limited number of times because over those uses your body will build up antibodies to the anti-venom, making the anti-venom ineffective.

Why are There More Venomous Species in Warm Places?

Contrary to popular belief, there aren’t more venomous species in warm places, at least not as a proportion of species. The majority of venomous species on Earth are ectotherms, organisms whose body temperatures are regulated by their surroundings. They can only really have short bursts of energy, so instead of chasing down prey and running away from predators, they needed a different strategy to allow them to survive and so many of them evolved venom. There is a greater diversity of ectotherms in warm climates, so it only stands to reason that there will be a greater number of venomous species. However, this doesn’t mean that there aren’t venomous species in cold places.

Evolutionary History and Venomous Species

Biodiversity alone isn’t the complete answer to this question. It also depends on evolutionary history. For example, if you had come to Australia 20 million years ago, there would have been no snakes at all. The venomous ones got here first and the non-venomous came after. This pattern is very strong and doesn’t seem to be explicable any other way. For instance, in Hawaii, there are no venomous snakes and the same goes for Jamaica. These are warm places that just haven’t evolved or have lost any venomous snakes that they may have had.

Conclusion

As we delve into this complex topic, we realize just how many mysteries are still out there. For example, why are some species deadly venomous and in others the venom is pretty weak? Another strange observation is that a lot of snakes that have evolved more recently have actually lost the ability to produce venom. The successful snakes are the ones that left it behind and they gave it up, and they’ve proliferated despite not having venom. If you have thoughts about this or any other mysteries regarding the global distribution of venomous species, feel free to share them.