Just as deadly predators have evolved ingenious ways to lure and catch their prey, so too have animals developed surprising and unexpected methods of escape. From fish that fly and lizards that squirt blood from their eyes, to insects that wear dead ants as a disguise. Welcome to the weird world of unusual defense mechanisms.
The Bombardier beetles (Carabidae)
These insect warriors made up of over 500 species get the name from the ability to spray a burning chemical cocktail from their abdomens. The anatomy underlying this defence mechanism is an incredible example of evolution with hydroquinone and hydrogen peroxide safely stored in separate body cavities. When brought together though, they react, heating the mixture to near boiling point and creating gas which forces it out of their body. Unsurprisingly, this chemical reaction can be lethal to attacking insects.
Flying fish (Exocoetidae)
Sometimes if you need to escape a predator, it pays to simply break all of the rules. That is the approach taken by the flying fish, of which there are more than 60 species present across all of the world’s oceans. As the name suggests, flying fish have long wing-like fins and a powerful tail that allows them to propel themselves out of the water and glide for considerable distances. This remarkable ability to evade predators seems to have served them well for over 65 million years of evolution.
Many of us will have heard of octopus and squid releasing a cloud ink to conceal their escape, but in dire situations they have another trick up their tentacles.
Called the ‘blanch-ink-jet manoeuvre’, this is where animals release a smaller amount of ink together with mucus, which causes the cloud to hold its shape apparently resembling a fake squid. Several of these are often released, around about the same size and volume as the fleeing animal, whilst it changes colour as an added distraction. Many predators have been observed to attack these mucus blobs by mistake whilst the prey makes a speedy getaway.
Don’t upset a vulture because they might just vomit on you. Defensive vomiting, to give it a technical term, is a primary defence for many vulture species as well as other birds such as herons and gulls. Whilst fairly self-explanatory, the particularly vile concoction of semi-rotting meat and foul-smelling digestive juices can be surprisingly effective.
Horned Lizard (Phrynosoma)
The horned lizards of the southern USA have many of the normal defences that you might expect in a small ground reptile. Excellent camouflage, armoured skin and they can run in short bursts if approached. However, as a last resort, a handful of species have evolved the ability to squirt a stream of blood from their eyes. They do this by rupturing blood vessels around the eyelids, and the blood, which can be launched over a meter, is said to taste terrible.
Japanese honey bee (Apis cerana japonica)
The innocuous looking Japanese honeybee is similar in many ways to the more widespread European species, but faced with the threat of deadly giant hornets it has evolved a remarkable defensive strategy: It cooks them alive.
Hornets are huge by comparison, so for honeybees their strength lies in numbers. If an intruder is detected, in order to defend the hive hundreds of honeybees mob the hornet forming a tight writhing ball of insects. Then, they begin to vigorously vibrate their flight muscles generating heat and respiring CO2. This combination begins to raise the ball of insects to a critical temperature of 46°C. This temperature kills the hornet, whilst the clever honeybees have evolved to survive up to 50°C.
Blast ants (Camponotus saundersi)
Found in Malaysia and Brunei, these industrious little insects have evolved a heroic last line of defence against predators. Termed autothysis, this is the process where an animal destroys itself via an internal rupturing or explosion of an organ. Blast ants have a pair of oversized poison filled glands that run the length of the body. Should they be losing a battle, they can rupture these glands spraying this corrosive and irritant chemical in all directions.
This bizarre frog from Cameroon was only described in 2008. Amongst a number of odd features (it grows hair, for instance), is the ability to break its own bones as a defence mechanism. Despite being a rather drastic last resort, these bones then puncture the skin creating sharp claws, which are thought to help the species escape predators. Unfortunately, this is only known from dead specimens, so exactly how this works in practice remains a mystery.
Mantis Shrimp (Stomatopoda)
Sometimes offence is the best defence, and few crustaceans have developed such a fearsome reputation as the mantis shrimp. A group of over 400 species growing to more than 40cm, the mantis shrimp are specialist predators that use lightening fast attacks with powerful claws to spear, stun or dismember their food, and as such many predators (and people!) give them a wide berth. Amongst aquarists they have been known to shatter aquarium glass with a single strike.
Assassin bug (Acanthaspis petax)
What better way to disguise yourself from predators, than to carry the dead bodies of ants around on your back? That’s exactly the gruesome strategy that this unusual insect from Malaysia has adopted. Whilst debate raged for years as to exactly why assassin bugs engaged in this odd behaviour, scientific evidence has recently shown that an assassin bug without a ball of ants is up to ten times more likely to be recognised and eaten by predatory spiders. So, it turns out that this strategy is surprisingly effective. Great news, unless you’re an ant of course.