In the natural world, survival isn’t just about strength or speed—it’s a high-stakes battle of wits, chemistry, and sometimes downright bizarre biology.
From cheetahs chasing gazelles across the savannah to male ducks firing exploding penises at unsuspecting females, evolution has created some of the most devious and astonishing arms races you’ve ever seen. These battles of predator and prey, plant and pest, and even sex and virus, prove that in nature, being clever can be just as deadly as being strong.
7 best animal arms races
FIRST PAST THE POST: CHEETAH vs GAZELLE
Two of the planet’s fastest animals are predator and prey, seemingly locked forever in an evolutionary arms race toward greater and greater speed. Where cheetahs currently have the edge on pace (95kph or so), gazelles pip them on stamina and possess an enhanced knack for dodging and weaving.
- These 9 ruthless, brutal cheetah photos reveal the raw power, speed and lethal grace of Africa's fastest cat
- Just how are cheetahs able to run so fast? All you need to know about the beautiful big cat, including the secrets behind its phenomenal speed
THE EYES HAVE IT: SQUID vs SPERM WHALE
The enormous eyes of deep-sea squid including giant squid and the Humboldt squid have long mystified scientists – after all, fish and marine mammals have eyes only a fraction of the size. One hypothesis, tested by researchers at Lund University in Sweden, suggests that they could have developed due to the evolution of a super-predator: the sperm whale.
CALL FOR REINFORCEMENTS: PLANT vs CATERPILLAR
Plants are anything but victims, for they fight back against herbivores with gusto. One famous example is the toxic compounds in ragwort leaves. The cinnabar moth caterpillar munches ragwort foliage, over time forcing the plant to become ever more toxic in response; it has essentially made ragwort poisonous. In addition, some trees release chemical compounds that attract parasitic wasps whose larvae feast on caterpillars, while others cultivate viruses that cause caterpillars to explode.
- Just how poisonous is ragwort to horses and livestock? Should it be pulled up?
- This pretty flower is essential for pollinating insects, yet deadly for livestock – causing severe, irreversible damage to the liver
HACK ATTACK: BAT vs MOTH
Espionage, double-crossing, evasive action – each night the war between bats and their prey continues. Moths, being top of the list, have evolved a suite of sensory equipment to dodge the echolocating clicks with which bats hunt.
Some moth species immediately take to ground upon hearing them, or scramble the bat’s signal by sending their own confusing clicks back. But barbastelle bats have wised up – they reduce the intensity of their clicking as they close in on prey, hoping for a sneak attack.
THE SEXES AT WAR: DRAKE vs DUCK
Arms races also occur between males and females. Many male ducks have evolved an ‘exploding’ penis that they fire opportunistically into females. Sadly this behaviour brings with it a black market in sexually transmitted diseases, so to counter this female ducks have evolved a vagina like a maze, which helps block the entry of unwanted male penises.
- Which animal has the biggest penis? (Hint: it's probably not what you think)
- The world's 9 weirdest penises – including a detachable one that swims off after a mate and another that grows back three times
THE FIRST BATTLE: CYANOBACTERIA vs VIRUS
The most ancient war is that waged between viruses and bacteria. Socomplex has this arms race become that a litre of seawater may contain 10 billion virus particles, each of which aims to break the security codes of bacterial life, hoping to enter and cause havoc. At some point cyanobacteria evolved a ‘kill switch’ to buy some time in this bizarre battle, which is why many algal blooms seem to disappear almost overnight.
TOXIC COMPETITION: GARTER SNAKE vs NEWT
Amphibians are often well kitted-out when it comes to poison, but some take it to extremes. For example, the rough-skinned newt produces the same toxin as pufferfish, and induces paralysis and death in anyone stupid enough to swallow it. What drove the poor newt to this? Its main predator, the common garter snake. Every time the newts evolve new and highly noxious toxins, the snakes evolve an antidote.
