The "frost dragon," described by Troy in 1934, is the most wide-ranging dragon on the planet, known from Russia, the Yukon, and Greenland. It is an enormous flightless dragon, reaching lengths of fifty feet or more. Troy characterized it as a "slow-moving behemouth of the Arctic, the last relic of an age where giants moved across the Earth." This dragon is light blue with a dark blue band along the back. The vertebral spines which run from the shoulderblades to the tail are white. The creature's horse-like head is capped by a large, caudally-directed horn. Additionally, a thick fin erupts from the back of the neck, and the tail ends in a laterally-flattened section reminicent of the marine dragons. Cryodracos' feet are huge and four-toed (as are its forefeet). The animal is an obligate quadruped, and as Troy noted, it is a slow-moving one. The wings have shrunken to mere stubs above the forelimb shoulder and consist of mere struts of bone. However, the wings support a unique remnant of the wing surface--Cryodracos sports two high-rising "wing fins," one above each shoulder. Clearly derived from the wing surface, these immobile structures are more prominent in males than females.
Most interestingly, all four legs are covered in thick hair from the elbow or knee joint downwards, and the fur covers the feet entirely except for the claws, which stick out beyond it. Such an adaptation is not surprising in an Arctic animal, but it is unique among dragons. The chest is equipped with hypertrophied armor scales. The animal's mandible is strange in that two tusks erupt from its distal end and may be modified incisors. The dragons use their tusks to dig through the snow to find vegetation. Cryodracos is herbivorous, which may explain its large size (Carpenter, 2006).
Norman (1984) noted that the dragon will use its flattened tail to "dig" a hole for sleeping in. Cryodracos curls its head toward its fur-covered feet, and Norman wrote that the massive dragons looked like cats when asleep: "While surely a behavioral adaptation for dealing with the cold Arctic nights, one cannot help but laugh at the juxtaposition of a monsterous dragon adopting the same posture upon bedding down for the night as my wife's tabby cat." He noticed that from a distance, the only way one could distinguish a sleeping dragon from any other snow birm was the presence of wing fins, which, being immobile, rose from the top of the slumbering beast. Thankfully, the dragons do not have to deal with freezing temperatures all year long. During the summer months, the beasts shed most of their fur and become more active. The disparate small groups which roamed alone during the winter months will all gather into larger "local" herds during the summer. The dragons gorge themselves on fresh blooms and grass during the spring and summer, which is also when mating occurs.
Carlsbad (1988) has documented the animal's breeding behavior from courtship to birth. Males will court females by throwing their heads around, snorting, and swinging their tails back and forth, all to some imaginary internal rhythm. Willing females will lower their heads and go into what Carlsbad described "the bow pose adopted by playful dogs." Uninterested females, however, will ignore the male's advances entirely or, in some cases, will actually charge the male. The latter seems to occur most often between young males and older females. Conception can take up to fifteen minutes, and males who have mated with a female defend her from interlopers for the remainder of the breeding season. This is not to say that males are monogomous--they rarely choose the same female during successive breeding seasons. Females actually retain their eggs through the next winter, then lay the egg in the spring. Eggs hatch almost immediately, and the pup is self-sufficient right out of the egg.
Carlsbad suggested that two forces were at work to ensure the success of babies in an egg-laying Arctic animal. First, he noted the elongated development of the egg, in which the pup was essentially protected through its first winter, but the timing of development was such that as soon as the egg was laid, it hatched. This allowed the baby all spring and summer to grow. The second force is the species' superprecociality, in which babies are born entirely capable of finding food and defending themselves after leaving the egg. Pups have almost-completely ossified skeletons and all of their teeth. Adult females lay between ten and fifteen eggs. Pups grow very quickly, and after a hatchling length of fourteen inches, they reach about six feet by the time winter approaches. Growth virtually stops during the winter, and many pups do not survive their first winter. A full clutch of fifteen pups will usually be reduced to four or five survivers by winter's end, although the remaining pups will usually have no trouble surviving their next winter. The dragons grow about six feet a year, and their growth stops when they reach about fifty feet. The oldest dead dragon known was 57.
Originally described based on the Russian species, Cryodracos has been variously assigned to different species or different subspecies of the same species once the Canadian and Greenlandic populations were discovered. Modern draconologists have settled on two subspecies of C. pilopeda: C. pilopeda canadensis for the Canadian and Greenlandic animals, and C. pilopeda caspia for the Russian population. Initial midochondrial comparisons have supported such a grouping (Lance, 2003). The animal's larger relationships are uncertain. Cryodracos is generally regarded as having an Asian origin, crossing the Berring Straight during the last ice age and expanding into Canada and Greenland. Two fossil specimens of a large quadrupedal dragon called Ambulodracos (Crank, 2000) are known from the Paleocene deposits of France, but whether that form is directly ancestral to Cryodracos cannot be stated with certainty. If the two are related, that would make Cryodracos' lineage one of the most ancient among living dragons. Irwin (1996) suggested that Cryodracos' ancestors may have been similar to Sinuospondylus.
Troy, R. (1934). The Arctic dragon, Cryodracos pilopeda. There be Dragons 18: 823-856.
Carpenter, K. (2006). Biggest of the big: a critical re-evaluation of the mega-sauropod Amphicoelias fragillimus Cope, 1878. New Mexico Museum of Natural History and Science Bulletin 36: 131-137.
Carlsbad, C. E. (1988). The mating and breeding habits of Cryodracos pilopeda. Canadian Journal of Science & Research 43(2): 345-387.
Lance, B. (2003). Initial genetic testing supports subspecies split of Cryodracos pilopeda into two distinct populations. Natura Historia 412: 889-894.
Crank, E. R. (2000). A large new fossil dragon from the Paleocene of France. European Journal of Draconology 101(4): 512-518.
Irwin, B. (1996). A revised phylogeny of the extent Draconia. In A Brief History of Draconology (Suet & Svenson, eds.). Prince Rupert Press: 56-73.