The lack of wear on anomalocaridid mouthparts suggests they did not come into regular contact with mineralised trilobite shells, and were possibly better suited to feeding on smaller, soft-bodied organisms by suction, since they would have experienced structural failure if they were used against the armour of trilobites. "A. canadensis" may have been capable of feeding on organisms with hard exoskeletons due to the short, robust spines on its appendages. However, as opposed to "Peytoia" whose mouthpiece is more rectangular with short protruding spines, the mouthpiece of "A. canadensis" has a smaller and more irregular diamond-shaped opening, not permitting strong biting motions, and indicating a suction-feeding behavior to suck in softer organisms.