By James Duncan
The weaponry possessed within the natural world has undoubtedly fascinated humans through the ages. Whether it's horns, tusks, antlers, teeth, claws, talons, fangs or stingers; animals have developed a hugely diverse suite of weapons in order to triumph in the evolutionary arms race. This race, in essence, is survival and it drives the ongoing evolution of these weapons to the extreme. Of course, animal weapons aren't a recent development - it only takes a visit to a Natural History Museum to notice Cretaceous-era Stegosaurs with fearsome-looking metre-long spikes and plates, armoured Ankylosaurs with huge, bony tail-clubs, Ceratopsians (think Triceratops) with a bewildering array of pointy facial defences and Saber-toothed Cats with rather intimidating canines.
Fiddler Crab © Wilfredo R. Rodriguez H.
Extrapolate that into modern times and we have Elephants that wield tusks weighing more than a fully-grown man; Deer that flaunt antlers more than 6ft wide; Narwhal that brandish a spiralled tooth more befitting of a mythical Unicorn; Chameleons that fire a muscular 'grappling-hook' up to twice their body length; male Fiddler Crabs twirling a massive 'cartoon claw' that comprises half their total weight; a multitude of fish whose oversized teeth don't even fit within their skull and mammals who carry their own spiny armoury around on their back, our very own Hedgehog a prime example. This is to name but a few as the variety is endless, and utterly fascinating.
Hedgehog © Hugh Clark FRPS
So, the question is, why do some weapons reach such extreme proportions? The 'ornamental' nature of weaponry undoubtedly points to a key factor being sexual selection. Afterall, the appeal of animal weapons isn't limited to the species in question; humans have endlessly coveted the greatest of these, symbols of grand splendour and outright wonder. They're ingrained in human culture, represented from the earliest cave paintings to modern day logos of corporations selling clothes, cars, alcohol, firearms and a whole lot more.
However, sexual selection is multifaceted and the development of these weapons is complex. Though many do serve as efficient armament in combat, most function as a symbol for individuals to assess the potential danger of their rivals. Escalation into full-blown combat may result in either serious injury or death, so ideally they serve as a way to resolve conflict peacefully. Usefully, they also serve as a direct indicator of individual body condition, helping to avoid many males from entering contests they just can't win. Neither male in that scenario would benefit from an energy-sapping brawl.
Red Deer stag © Peter Brooks
Here in Britain, of our six Deer species (of which only Red & Roe are truly native), it's the Red and Fallow that exhibit the most spectacular outgrowths. Antlers grow at a tremendous rate, faster than any bone, in any animal, anywhere on earth. It's incredible to consider that they may hit peak size in just a few months. This is far from an easy process, as the calorific energy required to produce such outrageous structures physically depletes the rest of the animal's skeleton. With Calcium and Phosphorous in high demand, these deer essentially suffer from Osteoporosis, each and every season. It goes without saying that engaging in bone-splitting combat at a time when the bones are especially weak is not a recipe for good health. Many stags and bucks emerge from the 'deer rut' in appalling condition, desperate to restore body condition or face certain death.
Fallow Deer bucks © Dave Kilbey
Considering weapons convey such useful information to rival males, it makes sense that 'showing off' the weapons also proves attractive to females, allowing those with the most impressive adornments a greater choice of mates. It seems weapons may evolve to their extreme where critical resources, perhaps limited by space or time (or both) are eminently defendable and give rise to immediate mating opportunities. Of course, the benefits have to outweigh the costs of producing (and carrying) such awkward and unwieldy armaments.
Of course, these weapons are not the preserve of the planet's largest beasts. In fact, many of the most impressive come courtesy of those creatures lacking a backbone; the invertebrates. Some insects possess the most dazzling of weaponry, often far exceeding their body size. They tend to be at their most bizarre amongst the Beetles, perhaps unsurprising considering they constitute around a quarter of all described species on Earth. The Scarab or 'Dung Beetles' wield almost every derivative of horn imaginable, the naming of the most famous truly encapsulating their look; Rhinoceros Beetle, Elephant Beetle and Hercules beetle. Back here in the UK, it's the Stag Beetle that parades the most extravagant weapon, a pair of hugely enlarged mandibles (mouthparts) used for casually hurling rival males from tree-based feeding sites where the females visit. It might be a long drop back to Earth for the loser.
Stag Beetle males © Hugh Clark FRPS
It isn't only males. Many female beetles, fish, crustaceans and reptiles also bear weapons, used largely in either defending their young or protecting a precious food resource, perhaps driven by natural selection rather than sexual.
Clearly, weapons used purely for defence are one thing. But what about weaponry used for catching prey, weaponry for attack? What if the weapons used don't even belong to the animal in question. Many animals are of course highly adept at the utilisation of tools. Aside from Homo sapiens, the 'Great Apes' have an extensive ability to fashion spears and improvise their own 'cutlery', whilst Cephalopods, (Octopus, Squid, etc.) Corvids (Crows) and Dolphins all demonstrate remarkable feats of brainpower, their capacity for problem-solving when catching prey practically unrivalled in the animal kingdom. Some animals however, if lacking in their own weaponry, employ that of others. In the Pacific, a Boxer Crab may flaunt a pair of 'Sea Anemone boxing gloves', a rather useful device for stinging pretty much anything it pleases, whilst a Blanket Octopus may casually rip the tentacles from a highly toxic Portuguese Man-of-War and deploy them like a venomous version of Indiana Jones' whip.
Boxer Crab © 2012 Eliot Ferguson
But what about weaponising humans? Or at least weaponising our technology. The humble Gull may be a good example. Familiar to all, many Gulls face the endless task of breaking into one of their favoured delicacies - coastal bivalve molluscs. Deploying a 'hard surface' to maximum effect, molluscs have their own strategy thrown right back at them; in the form of tarmac. Some particularly innovative Gulls don't stop at dropping the bivalves from a great height; they may drop them onto roads, relying on the crushing power of our vehicles to release the feast within. It may not be a fair fight, but it's certainly an effective way to harness our predictable movements for their ultimate gain. Who'd have thought, a Herring Gull making a weapon from your car.
Herring Gull © Nigel Symington