cruising speed of and a burst swimming speed of around , making Cretoxyrhina possibly one of the fastest sharks known. For comparison, the modern great white shark has been modeled to reaches speeds of up to and the shortfin mako, the fastest extant shark, has been modeled at a speed of . Life history Reproduction Although no fossil evidence for it has been found, it is inferred that Cretoxyrhina was ovoviviparous as all modern mackerel sharks are. In ovoviviparous sharks, young are hatched and grow inside the mother while competing against litter-mates through cannibalism such as oophagy (egg eating). As Cretoxyrhina inhabited oligotrophic and pelagic waters where predators such as large mosasaurs like Tylosaurus and macropredatory fish like Xiphactinus were common, it is likely that it also was an r-selected shark, where many infants are produced to offset high infant mortality rates. Similarly, pelagic sharks such as the great white shark, thresher sharks, mako sharks, porbeagle shark, and crocodile shark produce two to nine infants per litter. Growth and longevity Like all mackerel sharks, Cretoxyrhina grew a growth ring in its vertebrae every year and is aged through measuring each band; due to the rarity of well-preserved vertebrae, only a few Cretoxyrhina individuals have been aged. In Shimada (1997), a linear equation for calculating the total body length of Cretoxyrhina using the centrum (the body of a vertebra) diameter of a vertebra was developed and is shown below, with representing total body length and representing centrum diameter (the diameter of each band). Using this linear equation, measurements were first conducted on the best-preserved C. mantelli specimen, FHSM VP-2187, by Shimada (2008). The measurements showed a length of and weight of about at birth, and rapid growth in the first two years of life, doubling the length within 3.3 years. From then on, size growth became steady and gradual, growing a mean estimate of per year until its death at around 15 years of age, at which it had grown to . Using the von Bertalanffy growth model on FHSM VP-2187, the maximum lifespan of C. mantelli was estimated to be 38.2 years. By that age, it would have grown over long. Based on allometric scaling of a great white shark, Shimada found that such individual would have weighed as much as . A remeasurement conducted by Newbrey et al. (2013) found that C. mantelli and C. agassizensis reached sexual maturity