Everything is out to get you.
This may sound like a rather paranoid statement, but in the natural world it’s true. There is always another organism planning your downfall. Whether it be another species or one of your own, someone always wants your position, your power, your partner or even just to enjoy you as a delicious snack. But what do you do if you aren’t the biggest out there? Or the strongest? Or the most deadly? You have to find a different way to defend yourself. A way so distracting or intimidating, even the bravest of creatures will steer clear. Many species have developed some gruesome, clever and downright terrifying ways to defend themselves and here, we will look at a few of the more interesting ones.
I became interested in this subject when a friend introduced me to the Hairy or ‘Horror’ frog (Trichobatrachus robustus). This African species has gained notoriety due to its obscure defence strategy, first discovered in 1900. The Hairy frog has the ability to produce ‘claws’ and it does this by ‘breaking its own bones’. Whilst relaxed, sharps barbs remain hidden beneath layers of tissue in the frogs’ hind feet, connected to a muscle on one side and a small bone on the other. When the frog feels the need to defend itself, this muscle contracts causing the claw to break away from the bone and pierce through the skin. The amphibian will then drag and swipe these spikes across the skin of the threat, causing severe cuts and scratches. The claws are not the same as the standard we would expect from other animals. They are made only of bone, with no keratin layers at all. It is thought that the claws only retract when the frog relaxes again, causing scientists to come to the conclusion they are only used in defence, although there is an argument the claws could be used for climbing. Unfortunately for the frog, it has one adversary which has found a way to get past these claws: humans. Cameroon hunters kill the frogs using long spears before roasting and eating them. They avoid touching the frogs before killing them as the claws are incredibly painful and can cause deep wounds to the skin.
The Texas Horned Lizard (Phrynosoma cornutum) is another pro at protecting itself. One of its main defences is that its colouration and scaly like skin makes an excellent camouflage against the dry, dappled landscape it lives in. But camouflage will only go so far as o, the Texas horned lizard resorts to self defence mechanism number 2: like a Puffer fish, it expands itself. The logic behind this is not to make itself seem bigger, but to puff out all of the horned scales it has on its body. This should make the lizard an unpleasant mouthful and prove rather tricky to swallow. But if these methods do not work and a predator is still hanging around, then this reptile has a final trick still up its scaly sleeve – it has the power to shoot a stream of blood out of its eyes. This stream is squirted out of the corner of the lizards’ eye and can travel up to 5ft. The point of this bloody evacuation is twofold; on one hand it could confuse a predator, giving the horned lizard extra time to make an escape. But the blood also contains a chemical which is unattractive to canine species as it has an extremely unpleasant taste and upon realising this, the predator should hopefully be put off.
Generally, when we associate oil with birds it is due to a tragedy, where oil has caused nothing but detriment and destruction to various feathered species. But in the case of the Fulmar bird, oil is not always necessarily a bad thing. Fulmar birds (Fulmarus glacialis) have the ability to produce their own oil; a disgusting, foul-smelling secretion which is said to be able to stain clothing for years. This oil actually has two uses; feeding and defence. The yellow stomach oil, which is secreted from the Fulmar’s throats, is full of vitamins, notably A and D, which is useful for young chicks. However, the oil can also be projected in a series of shots towards a threat. If this threat is another bird then the oil is particularly effective as, in the instance of the clothes, Fulmar oil is incredibly difficult to wash or preen off. Whilst the sticky residue and colouring may reduce in time, it is the smell which lingers on, with some reports of feathers retaining the scent for over 10 years. It is not just the adults who have this excellent ability. The chicks can also spit oil and as they have no other defence, they tend to do this a lot during their first few weeks of life, including at their parents whom they do not recognize until they reach around 3 weeks old. Luckily for the Fulmar however, their own oil does not affect them as they seem to have immunity to it. It might also be of interest to know that the name ‘Fulmar’ is thought to have been derived from the Old Nordic words ‘fúll’ and ‘már’ which translate as ‘foul’ and ‘gull’, rather apt.
One of the more recent interesting defence discoveries is that of the Octopus squid (Octopoteuthis deletron). In 2012 this squid was observed firing off its own limbs in order to distract predators whilst it made a getaway, later re-growing the arms it had lost. Scientists tested this observation by locating a squid and poking at it with a bottle brush. Sure enough, the squid grasped at the brush with two tentacles and made a quick escape – leaving the two arms wriggling around in the bristles. It is thought that this technique would be enough to confuse a predator or even leave it to feed upon the two tentacles whilst the squid made its retreat. The squid’s which have been observed have all had limbs of different lengths, leading scientists to believe that this expulsion of arms is not uncommon. Re-growing body parts is not unusual in the natural world; several different creaturess including Axolotls, Sea Stars and various lizard species can all regrow body parts.
You would have thought that a stealthy set of pincers would be enough defence, but it would seem that the aptly named Boxer, or Pom-pom, crab (Lybia tessellata) doesn’t think so. These crabs have developed the most incredible (and adorable) habit of carrying sea anemones around in their claws. If threatened, the crab will then wave said anemones in the face of its predator (such as a goby fish), hopefully causing them to retreat. The crab favours the anemone species Triactis producta or Bunodeopsis spp. as these both have stinging tentacles called cnidocytes. These anemones are not just used for protection however, as they can also be used to catch food for the crab. By waving the anemone, the crab can catch food particles in its tentacles which the crab can then remove and eat for itself. The crabs have adapted to this defence because their own pincers are extremely small and not much use against larger fish. In fact, so adapted are these crustaceans to holding the anemones that they have learnt to use their second pair of legs to tear up food and feeding themselves with.
EDIT: A friend who has worked with these crustaceans told me this: “I seem to remember that if one (anemone) dies or gets lost, [the crabs] tear the remaining one to stimulate reproduction so they can have two again!” Kai Cursons
These are only some of the strange but exciting defence mechanisms used in the natural world and with the world ever evolving and still so much undiscovered, there may be more unusual forms of defence that we aren’t even aware of yet….
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