If we are to believe that these sightings indicate that megalodon may still be alive, then the hundreds recorded for the Loch Ness monster and sasquatch should be enough to write up a scientific description of each and justify governmental funding to support formal research expeditions to Scotland and the Pacific Northwest. In reality, whale sharks have white spots, and have a very wide, prominent head. In any case, despite the actual identities of the sharks spotted, the fact remains that there are only a few, questionable eyewitness accounts to go on. Dr. Shuker clings to the datings by Dr. W. Tschernezky of two teeth dredged from the Pacific as evidence for his theory. In fact, the wide consensus today among shark biologists and paleontologists is that the teeth were reworked from older deposits, and then redeposited in much younger sediments.
Paleontologists look on such evidence as good grounds for inferring the extinction of an animal.
Sharks lose hundreds of teeth each year, so if megalodon were still alive we would expect to find many teeth in post-Pliocene deposits. Furthermore, Tschernezky only used the lower value of the manganese dioxide deposition rates to obtain his age estimates. By using the higher values for manganese deposition, one obtains dates for the teeth at 1214 years old and 2600 years old, respectively. It is a mystery that Dr. Shuker and other proponents of megalodon survival have never seized upon this fact to help support their claim. They would be in error to do so, however, as the large discrepancy in dates caused by the rather wide range of possible depositions of manganese is indicative of the unreliability of this method of dating.