Sea-serpents
Sea-serpents of varying sizes can be found in all major oceans and seas. Those in the Atlantic Ocean reach no more than twelve feet even in the warmer waters off the coast of Brazil. Observational data on the sizes of Pacific serpents is scarce since they usually dive when approached by ships. Smaller serpents are found in the China Sea - the Chinese call them kiao, or sea-dragons.
Sea-serpents seize prey, such as swordfish or tunnys (tuna), by wrapping themselves around their targets and strangling them. A ship attacked by a large serpent must above all prevent the serpent from "looping" and damaging the ship beyond repair.
The HMS Allegiance was attacked by a sea-serpent in the Indian Ocean in 1806 while en route to China. This serpent is thought to be the largest sea-serpent recorded by Europeans. It was at least 250 feet in length, over twice the size of a Regal Copper, although the silver-grey body was less than 20 feet in diameter. Its head, shaped similarly to that of a dragon, was larger than Temeraire's, with a rounded snout, ridges of webbing and luridly orange eyes larger than dinner platters. Its neck was clad in thickly overlapping scales, blue and silver-gilt. Its forelegs were spindly in proportion to the rest of its body, with webbing stretched between relatively long, taloned fingers. Its scales shaded to deeper blue and purple iridescence along the length of its body.
The serpent apparently had a layer of pale, grey-white blubber underneath its skin. If this can be compared with the blubber of whales and dolphins - warm-blooded animals which adapted to life in the sea after evolving on land - it suggests that sea-serpents, like dragons, are warm-blooded and that they may have evolved from terrestrial creatures. The disproportionately large eyes may also be an adaption to low light conditions underwater.
Overall, it appears to be entirely possible that sea-serpents and dragons share common evolutionary origins (see also discussion at Draconic Taxonomy).
The intelligence of sea-serpents - or lack thereof - is a matter of some debate. To William Laurence aboard the Allegiance, for example, the lack of sentience in the serpent's eyes was entirely obvious. He also pointed out that the serpent appeared to have no spoken language, that she had eaten ten of the human crew and that in general sea-serpents could not be tamed for human use.
Temeraire strongly rejected the notion that knowledge of human languages and a willingness to be tamed by humans are necessary proofs of intelligence. He instinctively considered the serpent to be sentient and was deeply disturbed by the fact that he had been forced to kill her, after failing to communicate to her that she should leave the ship alone.
It should be noted that at the time, Temeraire had not yet learned Durzagh, a draconic language spoken in central Asia which appears to be related to draconic languages spoken in eastern Europe and southern Africa. It would have been interesting to know whether or not the sea-serpent would have recognized Durzagh to any degree.
As for Laurence's argument that eating humans proved that the serpent was not intelligent, feral dragons in Britain are quite willing to eat humans, when available, unless dissuaded by other dragons who are or have been in harness.
