Tasmanian Devils are one of the few species on Mobius that don't share the same intelliegence as most Mobians. During ancient times, a rogue group of Echidnas from Albion used genetic engineering to transform a tribe of Tasmanian Devil Mobians into less intelligent vicious dogs. (SSSM: #2)

Their keen sense of smell makes them good for tracking scents, so they were used by Geoffrey St. John, Smiley, and Fleming to help find the prisoner Sonic the Hedgehog after he escaped from a crashed plane headed for the Devil's Gulag. (StH: #48)

Thrash is the only known example of a sentient Tasmanian Devil on Mobius. Apparently the rogue group of Echidnas weren't able to change all of the Tasmanian Devil Mobians into simple dogs. (SU: #11)