I began to study the bottlenose dolphins in the IRL in 1974 in cooperation with SeaWorld. Money for dolphin studies is always in short supply and one of the easiest (and smelly!) ways to learn about them is to pick up the animals that are found dead on the beaches. They are also called stranded or beached dolphins.
Dolphins die from many kinds of natural diseases but some as a result of human activities (entanglement in nets, for example). I picked up dead dolphins in south Florida from my base at the University of Miami and SeaWorld collected dead dolphins from the IRL from its base in Orlando. SeaWorld also rescued live stranded dolphins and manatees for rehabilitation. Since dolphins were protected by federal law in 1972, we all worked under permits issued to us by the U.S. government.
We would weigh and measure each dead dolphin and perform a necropsy (a dolphin autopsy) to collect tissue samples, parasites and stomach contents. When we were done, we cleaned the skull and collected the teeth. In our studies of dolphins, biology is very important to know how old the dolphin is. A dolphin is born with one set of teeth (20-25 in each of 4 rows in the bottlenose dolphin) that continue to grow a little bit each year.
The growth is not in the top (or crown) of the tooth but in the root. The part of the tooth that is in the jaw beneath the gum.