The proteins in question are rich in certain amino acids, including histidine and a modified form of tyrosine called Dopa. It is the other components that matter, the proteins and pigment that increase in concentration towards the tip. This lattice gives the beak its shape but not its mechanical properties, for while chitin is itself very stiff, the dissolved chitin-only beak had a uniformly low stiffness throughout its length. When Miserez dissolved all the components away aside from chitin, he found that this polymer forms an intricate network of fibres, just 30 nanometres thick. The stabbing point contains 60% protein and 20% pigment, which accounts for its dark black-brown colour. Towards the tip, the amount of both water and chitin fall, the levels of protein and pigment increase, and the beak hardens. Miserez found that the soft base is mostly water (70%) and chitin (25%). The Humboldt’s beak is made of four key ingredients, water, proteins, chitin (the polymer found in insect exoskeletons) and a dark pigment. They gradually cut sections away from the beak and analysed the mechanical properties and chemical composition of each one. The reason for these mass deaths is still unknown but Miserez and his Californian colleagues took advantage of the mysterious events to acquire a large supply of fresh beaks for study. Anatomy of a beakįor the past few years, huge numbers of dead Humboldt squids have washed up on the beaches of America’s west coast. Now, he wears a custom-made suit of fibreglass-and-Kevlar body armour before he goes in the water and his awesome first-hand account is well worth reading. The first time he tried it, they beat the crap out of him and dislocated his arm. To give you a sense of what they’re like, check out the experiences of Scott Cassell who has had more experience with the Humboldt squid than most and repeatedly dives with them. It possesses the large brain, colour-changing skill and excellent vision of other squid and to these, it adds an aggressive temperament, a two-metre long body, 36 sharp hooks in each of its 2,000 suckers, and a penchant for cannibalism. It is a fearsome predator also known, for good reason, as the ‘jumbo squid’ or ‘red devil’. The powerful beak is not the only reason to be wary of the Humboldt squid. It’s an absolute marvel of precision bio-engineering. It is this gradient that blends the mechanical properties of the beak into those of the tissue around it, and allows the squid to tear through the flesh of its prey and not through its own. Its chemical composition changes gradually along its entire length, so that the sharp, pigmented tip is a hundred times stiffer than the pliant, translucent base which connects to the soft muscle. The squid’s beak is not a uniform structure. With such mismatched tissues, how does the squid manage to use its killer mouth without tearing the surrounding muscle to shreds? When squids attackĪli Miserez from the University of California, Santa Barbara has found the answer. It’s made up solely of organic chemicals and manages to be twice as hard and stiff as the most competitive manmade equivalents.īy comparison, the mass of muscle that surrounds and connects to the beak is incredibly soft, the equivalent of a jelly hand gripping a bare metal blade. That’s all the more remarkable because unlike most animal teeth or jaws, it contains no minerals or metals. This combination of properties makes the beak harder to deform than virtually all known metals and polymers. The Humboldt squid’s beak is two inches long and incredibly hard (difficult to dent or scratch), stiff (difficult to bend out of shape) and tough (resistant to fractures). The beak is a tool for killing and dismembering prey and the large Humboldt squid ( Dosidicus gigas) is known to use its beak to sever the spinal cord of fishy prey, paralysing them for easy dining. In the centre of their web of tentacles lies a hard, sharp and murderous beak that resembles that of a parrot. The bodies of squid, like those of their relatives the cuttlefish and octopus, are mainly soft and pliant, with one major exception.
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