Poison-Spraying Scorpions and Silk-Slinging Spiders: 10 Animals (and a Plant) That Use Projectiles

Most animals rely on fangs, claws or venom to fight - humans being the notable exception. However, there are a few non-humans who prefer to deal with things at a distance - let's take a look at...

1. Octopus Oceanic Ordinance
2. Glue-Spitting Velvet Worms
3. Poison-Spitting Spiders
4. Acid-Spraying Whip Scorpions
5. Blasting Bombardier Beetles
6. Silk-Slinging Bolas Spiders
7. Santiano the Stone-Stashing Chimpanzee
8. Poison-Spraying Scorpions
9. Bristle-Kicking Tarantulas
10. Pressure-Powered Pistol Shrimp
11. Fruit-Detonating Dynamite Trees

The siphon of an octopus can jet water... or more! (Oleksandr Sushko)

1. Octopus Oceanic Ordinance

Octopuses are smart mollusks, so perhaps it shouldn't be surprising that these canny cephalopods have figured out how to throw things underwater.  There seems to be two styles - picking up debris then dropping it while jetting water from their siphon, or loading debris into their siphon and using it like a blowgun.

The second case is particularly entertaining, as researchers managed to film a veined (coconut) octopus hiding from predatory fish and briefly emerging to "snipe" with its siphon.  The fish seem to react in pain, and (when played in slow motion) the jets of water being fired at the fish contained small pebbles!

2. Glue-Spitting Velvet Worms

The velvet worms are not really worms... though they do have a velvety appearance. They resemble a caterpillar, but anything getting close risks a face-full of glue and being dissolved alive.

Velvet worms are living fossils - and predatory ones at that. Rather than relying on fangs or claws, they shoot jets of a rapid-setting slime from a pair of projections near their mouth. Typical prey includes crickets, spiders and other small invertebrates, all of which can be hit from around a foot away by the slow-moving marksman.

Prey caught in the slime find that it rapidly hardens, pinning them in place as the velvet worm trundles over, rips them open and injects them with a fluid that liquifies their innards. While it waits for this to happen, the velvet worm eats the protein-based slime - reduce, reuse, recycle, I guess.

3. Poison-Spitting Spiders

It turns out that spiders spitting poison isn't just a feature of videogames.  The Scytodidae family of spiders attack prey from a short distance, spitting a sticky fluid containing both silk and venom. 

 

One fairly common species is Scytodes thoratica, a spider found across a lot of the world. When hunting prey it approaches and the points its chelicerae (fangs) at the target, then contracts its muscles to spit a jet of this deadly fluid. The attack is fast but short ranged (it sprays at 30m per second, but reaches only slightly more than 1cm in distance) and launches in a zig-zag pattern, thanks to the spider vibrating its chelicerae. 

The spider can even make these attacks without being able to see prey, relying on vibrations to detect a target - and the victim will quickly find itself subdued as the mass congeals and contracts on impact!

Note the thin tails on these "vinegarroon" whip scorpions... (Daniel_Bechmann)

4. Acid-Spraying Whip Scorpions

Whip scorpions lack the stingers and venom of their cousins (though they do look like them.)  That said, the long-tailed varieties do have a nasty trick - they can spray an irritating acid mist.

The acid isn't incredibly dangerous - most rely on acetic acid (the same thing you find in vinegar) which is enough to damage insect exoskeletons or irritate human eyes - in Mastigoproctus giganteus the concentration can be as high as 85%.  It can also have an unpleasant smell, with an alternative name for some of these creatures being "vinegarroon."

5. Blasting Bombardier Beetles

Bombardier beetles are nature's alchemists - when threatened, they can mix chemicals to produce a noxious chemical spray.

The style of these blasts depends on which species of bombardier beetle is producing them.  Many species rely on two glands containing chemicals (such as hydrogen peroxide and a hydroquinone) that squirt into a tough "reaction chamber" at the back of the insect.  The two chemicals react violently, producing heat and gas that drives a scalding spray of toxic, caustic chemicals out of the insect.

It seems to be an effective tactic - researchers have watched frogs "pass" on bombardier beetles (even dead ones) even before the "bomb" had to be deployed!

6. Silk-Slinging Bolas Spiders

Some spiders spin a web to catch prey, while others simply hunt with their own speed and agility. The bolas spiders take a little bit from both approaches, creating lines of sticky silk that can be whirled at prey.

These lines of silk have a small but sticky blob on the end, which acts as the "warhead" of the bolas. The spider waits in ambush, dangling the bolas whilst emitting pheromones that lure a moth close.

When the spider senses an approaching moth, it starts to whirl the bolas in the hope of hitting the moth as it flies past. A solid hit fixes the unlucky insect to the sticky blob, allowing the spider to reel in the prey for a poisonous bite.

Chimpanzees are known to throw things, but one stockpiled missiles... (Pixel-mixer)

7. Santiano the Stone-Stashing Chimpanzee

Chimpanzees are one of the better known users of projectile weaponry - after all, primates throwing feces is common feature of lowbrow comedy. There is one particular example that stands out though, a chimpanzee by the name of Santiano.

Keepers at Furuvik Zoo in Sweden found that Santiano had been calmly collecting stones before visitors arrived each day, carefully figuring out where bits of the concrete in his enclosure could be broken off. He would stash these missiles for use later in the day, when aiming them at visitors he didn't like.

This is a remarkable bit of behavior, as it seems to shows non-human carrying out forward planning.

8. Poison-Spraying Scorpions

Scorpions are known for their stings, but Tityus achilles can spray poison as well as inject it. The creatures have been observed launching their venom distances of up to 14 inches. Researchers think that is uses this tactic defensively, aiming the burst at the nose and eyes of an advancing predator to distract or potentially blind it.

While attacking a threat at range may be worth it, the technique is probably worthless for hunting. Not only does it waste a large amount of venom, any that hits an exoskeleton, fur or even unbroken skin would have little-to-no effect.

A few other scorpions (some of the Parabuthus genus) are known to spray venom, but Tityus achilles can actually dilute poison when spraying - it saves the concentrated venom for a sting.

Most New World tarantulas can kick urticating hairs at threats... (Mike_68)

9. Bristle-Kicking Tarantulas

Tarantulas are scary looking creatures with powerful jaws and a venomous bite. Not content with this, most New World tarantulas have another weapon in their arsenal... urticating bristles.

Urticating bristles take their name from nettles (whose genus is Urtica) and they can be found on a wide number of plants as well as some animals. These small hair-like structures differ in construction, but all can cause a great deal of irritation when stuck in skin or an eye.

When a tarantula armed with these bristles feels threatened it can detach and kick them at an aggressor, usually aiming for the eyes, mouth and nose. The barbed and irritating bristles make for a painful deterrent and distraction.

10. Pressure-Powered Pistol Shrimp

Featuring a set of mismatched claws, the pistol shrimp is the gunslinger of the aquatic world. In fact, the noise produced by colonies of these animals can interfere with sonar

The shrimp uses a large specialized claw to perform its namesake trick. One side of the claw features a socket while the other has a plunger that fits inside it. Snapping it shut forces water out of this socket, along a channel leading to the front of the claw.

The high pressure jet of water leaves a very low pressure area in it's wake, causing cavitation (the formation of air bubbles) as result. These air bubbles implode when pressure rises again, which can stun or even physically damage prey. This all happens extremely quickly, but when viewed with an incredibly high frame rate the "shot" can be seen moving through the water.

11. Fruit-Detonating Dynamite Trees

While the other entries on this list are animals, one plant gets a special mention - the sandbox or dynamite tree Hura crepitans.

The tree has poisonous leaves and bark, but it is the seeds that act as projectiles. When ripe, the tree lives up to the nickname "dynamite" as the fruits detonate and spray seeds throughout the surrounding area. The explosion is surprisingly potent, powered by tension built up inside the fruits as they dry. When the fruits burst they launch seeds at up to 70m per second, potentially carrying them as 45m from the tree.

Being caught in the blast is actually hazardous to humans and animals - while the projectile seeds lose energy rapidly, being near an exploding fruit can result in a lot of small wounds.

Thanks for reading - click here if you want to know about more weird natural weapons, or try...

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