Nature isn’t just red in tooth and claw – sometimes it’s downright bizarre. Across the animal kingdom, evolution has equipped creatures with an astonishing armoury of unconventional, often outrageous defence strategies.
Some wrap themselves in mucus sleeping bags, others weaponise their own skeletons or bodily fluids – and a few simply out-slime anything that dares take a bite.
Weirdest animal defence strategies
Armadillo girdled lizard
Coiled in self-defence, this armoured creature – the armadillo girdled lizard – turns its body into a formidable fortress to evade predators. For this creature, though, the behaviour is more about self-preservation, exposing attackers to its impenetrable spines while protecting its vulnerable underparts.
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Queen parrotfish
The queen parrotfish is by day a beautiful and diver-friendly reef fish. By night, it’s a reclusive slime-bag. Literally.
Come sundown, this watermelon-sized Caribbean gem slips into a crevice and, using special glands behind its gills, secretes a bubble of mucus that swells up and over its head like a diving helmet. The pouch spreads towards the fish’s tail and, within 30 minutes or so, the fish is resting inside a surprisingly spacious sac of slime.
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The clammy cocoon – in which the fish spends the entire night – has many benefits. It is laced with antibiotics that kill known parrotfish pathogens, and also physically blocks blood-sucking parasites from getting near the fish. In addition, it appears to seal in the sleeper’s body odour, masking it from scent-tracking predators such as moray eels.
And the instant the pod is disturbed or torn, its owner wakes up and high-tails it out of there. It’s like a high-tech tent with a mosquito net and burglar alarm system.
Sperm whale
Back in 2024, guests on a whale-watching trip in Bremer Bay, Western Australia, had a strange experience that left marine biologists scratching their heads.
They observed what appeared to be a pod of sperm whales defending themselves from a killer whale attack using a huge cloud of faeces – but was this on purpose, was it a chance occurrence or did the whales just have the crap scared out of them?
The group of sperm whales started to create a circle with their heads facing inwards and their thrashing tails pointed outwards – a formation known as a rosette, which has been reported to occur when pods are trying to protect a calf or injured individual. Although it wasn’t clear from the boat, the adults may have been keeping the young whale in the centre for safety.
Then, a large, dark faeces-filledcloud rose to the surface among the sperm whales and the orcas moved away from the sperm whales, staying in the area but keeping their distance.
North American horned lizard
North American horned lizards - also known as horny toads - are just 9cm in length, yet are equipped with an impressive arsenal of novel, powerful defences. They boast excellent camouflage, have armoured, spiky skin, and can inflate their bodies to double their size.
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But their real super-power is their ability to shoot blood – loaded with foul toxins gleaned from a diet of venomous ants – from their eyes, to a distance of up to nine times their body length.
So precise is their aim that these little lizards can see off wolves and coyotes many times their size, blasting the predators square in the face.
Spanish ribbed newt
When threatened by a predator, the Spanish ribbed newt takes spectacular offensive action. Not only does it exude a milky poisonous fluid from glands in its skin, it also has the perfect apparatus to administer it.
The Spanish ribbed newt – also known as the Iberian ribbed newt – has orange spots along its flanks, through which its ribs can protrude.
By flattening its body and arching its back, the newt swings its ribs forwards so that they are perpendicular to its spine. The ribs stretch the skin to the point that they burst right through it, producing a row of barbs down each flank that inject the poison into any predator foolish enough to venture too close.
Once the danger has passed, the amphibian simply pops its ribs back inside its body. And thanks to the newts' famous powers of regeneration, it can puncture its skin repeatedly, with apparently no ill effects.
Bombardier beetle
The bombardier beetle surely has one of the smelliest deterrents in the animal kingdom. When annoyed, they release a hot, noxious acid spray of hydroquinone and hydrogen peroxide from the tip of the abdomen - which can be fatal to predatory insects and a smelly experience for animals hoping for a quick bite.
Termites
A 'backpack' full of a toxic blue substance allows this termite to blow itself up, along with the threat, if its colony is invaded – a form of self-sacrifice for the greater good of the colony.
“In all cases, the released substance is sticky and binds to predators, congealing when exposed to air and causing distress, immobility or death to the target,” reported scientists in a review of self-destructive behaviour in social insects. "It is highly effective against other invertebrate predators but much less so against lizards or birds."
Sea cucumber
The sea cucumber is more deadly than it looks – in fact, it has an array of tools and weapons to ward off predators.
When pestered by a hungry fish or crab, this squishy invertebrate found worldwide can initiate rock-solid armour in seconds. Special compounds in its skin allow it to stiffen (and liquefy) its body wall on demand.
This is particularly useful on a reef - the critter can ooze into a crevice, harden in place and be virtually impossible to extract.
If harassed in open terrain, the sea cucumber may draw from a deeper, nastier place and violently eject its intestine and stomach out of its anus. This distraction buys it time to slip away. The innards are laced with poison, so the slightest nibble by its foe is sure to nip further pursuit in the bud.
But if the attack escalates, the annoyed cucumber finally explodes - literally tearing its body cavity and expelling toxins that can kill most organisms on contact, a chemical onslaught known as the 'cuke nuke'.
The gutless sea cucumber, unable to eat, absorbs nutrients through its skin and immediately starts rebuilding its insides. In about a month, the cuke is whole again - with the inner strength to take on what lies ahead.
Hagfish
Death by slime would not be a nice way to go. Hagfish are (probably) the slimiest animals in the world - and they can use their slime for lethal purposes.
These eel-shaped, jawless fish possess specialised slime glands that have two types of cell: mucous cells that release mucin and thread cells that exude skeins (loosely coiled fibres) of protein around 15cm long.
A Pacific hagfish, for example, can produce a litre in under 0.1 seconds. Hagfish slime is deployed as a defence to clog the gills of fish predators, causing them to suffocate.
Matador bug
Waving your limbs about doesn't seem like a very good way of defending yourself. In fact, rather the opposite – you would think all that activity would be the equivalent of screaming, "look at me, I'm over here!" But a recent study of matador bugs, published in Current Zoology, reveals that they wave frantically in the air as predatory mantids approach. Researchers think the waving display is triggered specifically by danger.
Observations of related insects in Panama, combined with analysis of online footage, revealed at least five other species in the same family also perform similar flag-waving, pointing to a wider evolutionary pattern. All these insects feed on passionflower vines, which are known to carry toxins – the researchers suggest the waving could therefore be a warning from the bugs of their toxicity.
Another theory is that the waving might confuse predators’ vision and make an attack more difficult. Either way, leg waving seems to be an effective defence.
Hairy frog
This frog has a clever survival trick. With the flex of a foot muscle, it can produce an arsenal of sharp, curved claws that snap out of its toes like switchblades. These thorn-shaped toe bones rapidly pivot when triggered, sending the pointed tip slicing through the frog’s skin and transforming its feet into formidable weapons. A few violent kicks can lacerate a foe and draw blood from an unsuspecting biologist.
These claws are comprised of the broken ends of the frog’s toe bones. Inside each toe of its rear foot, the last bone is attached to an anchor bone at the very tip of the toe. When needs must, it contracts muscles and tendons attached to the underside of this last bone, causing it to break away from the anchor bone and then swing downwards, puncturing and bursting through the skin.
