Shark Jaw Research Articles

Injuries to jackass penguins (Spheniscus demersus): evidence for shark involvement

An analysis is presented of records of injuries and the types of injuries to jackass penguins in Algoa Bay, South Africa, over a 10‐year‐period. Sharks are implicated in causing most of the injuries, but other possible agents are discussed. The types of injuries were categorized and compared to the dentition of sharks known to occur in the area. Using a life‐size model of a jackass penguin and preserved jaws of sharks, bites were simulated to establish the types of injury inflicted by different species. Certain injuries indicate attack by great white sharks, while others cannot be ascribed to any particular species. Most shark injuries show single jaw involvement, and range from small cuts across the feathers to the bird being cut in two. Sharks accounted for the highest number of identifiable natural causes of death, but the significance of shark attack as a mortality factor in jackass penguins is difficult to assess.

Size of the Great White Shark ( Carcharodon )

The maximum length of 36.5 feet (11.1 meters) attributed to the white shark (Carcharodon carcharias) by Günther and others is a mistake. Examination of the jaws and teeth of the specimen referred to by Günther and comparison with the jaws of white sharks of known length revealed a length of about 17 feet ( approximately 5 meters). The largest white shark reliably measured was a 21-foot (6.4-meter) individual from Cuba. Bites on whale carcasses found off southern Australia suggest that white sharks as long as 25 or 26 feet (7 (1/2) or 8 meters) exist today. The size of extinct Carcharodon has also been grossly exaggerated. Based on a projection of a curve of tooth size of Recent Carcharodon carcharias, the largest fossil Carcharodon were about 43 feet ( approximately 13 meters) long.