extended periods of physical struggling and stress. Skull and head morphology The mouths of Nile crocodiles are filled with 64 to 68 sharply pointed, cone-shaped teeth (about a dozen less than alligators have). For most of a crocodile's life, broken teeth can be replaced. On each side of the mouth, five teeth are in the front of the upper jaw (premaxilla), 13 or 14 are in the rest of the upper jaw (maxilla), and 14 or 15 are on either side of the lower jaw (mandible). The enlarged fourth lower tooth fits into the notch on the upper jaw and is visible when the jaws are closed, as is the case with all true crocodiles. Hatchlings quickly lose a hardened piece of skin on the top of their mouths called the egg tooth, which they use to break through their eggshells at hatching. Among crocodilians, the Nile crocodile possesses a relatively long snout, which is about 1.6 to 2.0 times as long as broad at the level of the front corners of the eyes. As is the saltwater crocodile, the Nile crocodile is considered a species with medium-width snout relative to other extant crocodilian species. In a search for the largest crocodilian skulls in museums, the largest verifiable Nile crocodile skulls found were several housed in Arba Minch, Ethiopia, sourced from nearby Lake Chamo, which apparently included several specimens with a skull length more than , with the largest one being in length with a mandibular length of . Nile crocodiles with skulls this size are likely to measure in the range of , which is also the length of the animals according to the museum where they were found. However, larger skulls may exist, as this study largely focused on crocodilians from Asia. The detached head of an exceptionally large Nile crocodile (killed in 1968 and measuring in length) was found to have weighed , including the large tendons used to shut the jaw. Biting force The bite force exerted by an adult Nile crocodile has been shown by Brady Barr to measure . However, the muscles responsible for opening the mouth are exceptionally weak, allowing a person to easily hold them shut, and even larger crocodiles can be brought under control by the use of duct tape to bind the jaws together. The broadest snouted modern crocodilians are alligators and larger caimans. For example, a black caiman (Melanosuchus