A six-legged animal used as a beast of burden throughout the empire. Unknown la the times of Muad'Dib, thorses were introduced on Arrakis after the ecological transformation of the planet was completed. Phylogenefccians and other biologists differ over its ancestry and origins. Its six-leggednes& is unique, for no other known mammal possessed six limbs, although a very few species found only on Ecaz have rudimentary mid-torso organs. However, these creatures, most notably the slandai and the plake, have no other resemblance to the thorse, and most authorities now feel the coincidence is merely accidental and that the thorse is the only true hcxaped. Long bred for strength and sturdiness, the thorse is particularly well suited to planets with a wide range of climates. The fur-bearing thorse (tharsus thorsensis meyersei) was hunted to the point of extinction after Leto n banned all trade in whale fur, but it was saved when Leto extended the ban to the thorse and other fur-bearing animals. Some authorities, most notably Noah Arkwright, maintain mat Leto himself was responsible for the introduction of the thorse throughout the Imperium. Arkwright suggests, with some cogency, that the slowness of die thorse-even the fastest beast is capable of little better than ten kph-would make its use for transportation difficult if not virtually impossible, and, as one unattributed cynic cited by Arkwright once remarked, "A population which walks is easier to control." Physical description of the beast is a far simpler task than tracing its phylogeny. Adult members of the breed have been known to weigh over 2000 kg and extend nearly six meters long. Despite their large size, their nutritional needs are relatively small, and the creature's multiple stomach-digestive systems permits ingestion of almost any type of vegetable matter. This fact alone permits its employment on many planets. Phylogenetically it appears that the thorse is unique.