Meeting Abstract
Due to the difficulties of observing in-situ behaviors at extreme depths, the feeding behavior of deep-sea fishes is rarely observed. However, gut-content studies reveal many species are capable of consuming prey that exceed 50% of the body length. Large needle-like fangs are a hallmark of predatory deep-sea fishes and thus are often implicated in the impaling of large prey. A recent modeling study of the viperfish (Chauliodus sloani) suggest that its enormous fangs are powered by weak adductor muscles. This raises a fundamental question: Are enormous teeth used for impaling or some other function such as caging? To answer this, we performed puncture-resistance test on typical prey items of C. sloani, species of the mesopelagic family Myctophidae. We found that myctophid scales are extremely puncture resistant, requiring 20-80 N for failure over a range of specimens 30-70 mm. Given the extremely low bite force of a viperfish, their fangs are incapable of piercing these prey. The bite force of C. sloani would have to be amplified 3,000-4,000 times to puncture the largest prey items it consumes. We therefore conclude that the fangs of a viperfish are not impaling devices, but rather likely used in caging.
