Do the bones of all Nile crocodiles have the same number of growth marks as their age? And can such growth rings be counted to accurately gauge the age of these reptiles? Is this also an accurate method to use when trying to "age" dinosaurs and other extinct and extant reptiles? No, not according to a Scientific Reports study by Prof Anusuya Chinsamy-Turan and Dr. Maria-Eugenia Pereyra of the Department of Biological Sciences at the University of Cape Town (UCT), South Africa. They found that the growth marks in crocodiles' bones cannot be used as a reliable indicator of age. The two UCT paleontologists further caution against using it along with derived growth curves to age extinct vertebrates such as dinosaurs.