The main prey of the strap-tooth beaked whale is considered to be oceanic squid species. In an extensive dietary analysis of 14 stranded whales from New Zealand and South Africa, 94.8% of the stomach contents were composed of cephalopods, with evidence of some fish and crustaceans. A difference in the shape of consumed prey was noted between male and female whales, but it was determined that both sexes targeted squid of a similar size. While adult males have a restricted gape size due to the position of their overlapping tusks, it is possible that this allows them to create more suction when feeding, allowing them to forage effectively on the same prey as females and juveniles.