A long-standing view holds that "Anomalocaris" fed on hard-bodied animals, including trilobites—making it one of the first predators—and its mid-gut glands strongly suggest a predatory lifestyle. However, its ability to penetrate mineralised shells has been questioned. Some Cambrian trilobites have been found with round or W-shaped "bite" marks, which were identified as being the same shape as the mouthparts of "Anomalocaris". Stronger evidence that "Anomalocaris" ate trilobites comes from coprolite, which contain trilobite parts and are so large that the anomalocarids are the only known organism from that period large enough to have produced them. However, since "Anomalocaris" lacks any mineralised tissue, it seemed unlikely that it would be able to penetrate the hard, calcified shell of trilobites. Rather, the coprolites may have been produced by a different organisms, such as the trilobites of the genus "Redlichia".