When an animal is prepared as a skeletal specimen, the side effect of the preparation process (either through maceration, dermestid beetles, manure, or burying) is that the bones fall apart as the tendons and connective tissue is removed. This includes teeth falling out of the jaws! With a smaller animal you can just glue the teeth back in but with something as large as a sperm whale you need something a bit stronger than just glue.

First, a note about Sperm Whale teeth. The lower teeth are quite large, the biggest on this specimen are nearly 10 from root to tip. Sperm whales only have teeth on the lower jaw. When the mouth is closed these teeth fit into grooves in the upper palate. When dissecting whales, we have seen tiny teeth that don’t actually emerge from the gums on the upper jaw, but that is a subject for another post! Our specimen has 23 rows of teeth and the animal was 15 meters long.

My coworker on this project, Mickel van Leeuwen from Inside Out Animals, is a skeleton expert. He had macerated the entire specimen (a process that can take longer than a year!) and then placed the teeth in the proper sockets. How do you know which tooth goes in which socket? The teeth get more C shaped as you get closer to the front of the mouth. The teeth in the back are almost straight, and those back teeth only have the smallest bit of wear on the tips (which is the part that would be emerging from the gums) and the farthest forward teeth have the most wear on them.

Mickel had actually drilled through the teeth with screws to secure into the holes in the jaw, so the teeth cannot fall out. The next step was filling in the gaps with either apoxy or dental plaster (which sets incredibly fast and has a nice fine grain) to cover up the screws. This is necessary not only to make the whole jaw look nice but to really secure the teeth. The teeth in the back of the jaw have shallower sockets, so for those we used two part apoxy mixed with white paint. After pushing the apoxy around the base of the teeth we did a bit of stippling to make it look more natural. For the front teeth which sit in deeper cavities, we used the dental plaster because it can be poured in to fill the very narrow gaps between the teeth and the lower jaw bone.

You will notice that our specimen is missing one tooth! Every whale that washes up in the Netherlands gets a full autopsy from the stranding team at Utrecht University. They slice the teeth into horizontal pieces: whale teeth grow rings like a tree, and that is how scientists can age them.