The cutthroat participates in a unique predator-prey relationship with the bull trout
that is key to ecosystem integrity across much of its natural range.
Cutthroat will readily interbreed with the closely related rainbow trout, producing
fertile hybrids commonly called "cutbow". As this species generally bears similar coloration and
overall appearance to the cutthroat, retaining the characteristic orange-red slash, these hybrids often
pose a taxonomical difficulty.
In addition, cutthroat will also hybridize with the O. gilae subspecies, the Gila trout and
Apache trout in regions where their ranges overlap.