Who’s tougher? Baby sharks or daddy sharks?

One would assume that since humans and many animals tend to get stiffer and perhaps tougher as they reach adulthood, the same would be true for sharks. A new study finds the opposite in these swift-swimming marine predators. The youngest sharks were stiffer and tougher than older sharks. Another key finding is that while scientists have historically looked at alternating patterns of mineralization on sharks’ vertebrae to determine their age, these patterns are not related to time.