Predation on Nautilus
Little has been written regarding predation on Nautilus, because information on the subject has largely been limited to inferences based on indirect evidence, such as healed injuries, shell breaks, and borings. For example, Willey (1902) remarked on the presence of healed severe injuries to the hoods of several males and speculated that they might be due either to attacks by fishes or to fighting between sexes. Haven (1972) regarded shell breakage and hood injuries in N. pompilius as a fairly common product of fighting within the species and demonstrated that the distinctive, V-shaped breaks so common in Nautilus shells are a product of biting (Haven, 1972, Figs. 4 and 5). Arnold (1985) described and categorized a wide variety of shell abnormalities in N. pompilius from the same region. In addition, evidence indicates that Nautilus is regularly preyed upon by Octopus, and attacks on Nautilus by fishes have now been documented. This chapter briefly summarizes the results of previous studies and presents new information regarding predation on Nautilus.