I think they are a Viking ship.
Vikings inhabited a cold and forbidding land. They were not numerous, nor endowed with natural resources. Nor were they known for their technology.
But the Vikings were fearless. They took to the seas, exploring and fighting to secure their future. They became expert navigators, ranging as far west as Newfoundland (the first Europeans in North America) and east to the Volga River, the Baltic Coast, Constantinople, Arabia, and the Fertile Crescent.
They became expert sailors and navigators. Vikings achieved these voyages thanks to their longships. These ships were narrow, long, and light, built for speed and capable of beach landings, forays into estuaries and intercontinental rivers, and long portages.
Like a Viking longship, the Cats are a product of necessity and deliberate design. They are built for a specific purpose, and can handle a variety of conditions. The Vikings, as much as any European people, adapted to their circumstances, and the Viking ship was their crucible.