The death of a whale can happen at sea or onshore if the animal beaches itself. Examining the dead whales can reveal many secrets like the cause of death, but also how a whale’s body works. In this post, we will explore the lesser-known area of cetacean research, post-mortem investigations, commonly known as necropsies. We will delve into how necropsies help us understand whales’ lives and their environment and ways to get involved in the world of post-mortem investigations!
Why study dead whales?
The main purpose of post-mortem investigations is to determine the cause of death of the stranded whale. Cetaceans hold a crucial position at the top of food chains, making them useful as indicators for their respective ecosystems. Any alterations in their habitat will affect all levels of the food chain, making their role even more significant. These investigations can reveal details about the animal that are impossible to observe while it is alive, such as the structure of internal organs, the presence of parasites or diseases, and even the types of food it consumes. Local governments frequently commission stranding organizations as they have a legal obligation to preserve the protected species of cetaceans as per (inter)national policies.
Photo: Jelle Boontje / Utrecht University
Post-mortem investigations of whales
Just like humans, cetaceans are complex beings with unique anatomy that requires specialized training to properly dissect. That’s why stranding research organizations often connect themselves with a university that has a veterinary pathology department. A lot of knowledge and expertise are available in such departments. Post-mortem investigations are a crucial part of cetacean research and involve examining the anatomy, physiology, and pathology of a cetacean after its death.
The cause of death of a whale can vary from ship strikes, starvation, and entanglement to infectious diseases. It is important to note that cetaceans are mammals and could carry zoonotic diseases that may be transmissible to humans, so proper safety measures should be taken when performing necropsies. This necessity of safety measures is why an affiliation with a veterinary pathology department is common. These departments work with various diseases everyday and have established protocols and facilities to manage them. I also want to emphasize to never touch a (living or dead) cetacean that you found on the beach because of the numerous diseases that you could expose yourself to!
Photo: Jelle Boontje / Utrecht University
A dead whale stranded, what now?
Stranding research organizations maintain networks with numerous dedicated and amazing volunteers who help register and collect dead whales from the stranding sites to the necropsy locations. In the event of a whale being too big for the necropsy room, the examination occurs outside, near the location of the stranding, either on the beach or in a harbor. The necropsy starts with weighing, measuring, and photographing the animal. Next, scientists will determine its age, class, and sex. The researchers will then externally examine the individual to look for indications of disease, skin lesions, or interspecific interactions. For example, harbor porpoises in the North Sea often have wounds from attacks of grey seals or bottlenose dolphins.
After the external examination, the necropsy staff starts dissecting the animal. The necropsy staff will remove, photograph and describe each organ, one by one, in the necropsy report. Further testing is then conducted based on the condition of the organs. These can include identifying viral or bacterial infections, for example.
Photo: Tjeerd Bakker
Necropsies of cetaceans also allow us to take many tissue samples, such as blubber for contaminant analysis, inner ears for hearing damage studies, the contents of the stomachs for diet research, and so much more. This is one of the reasons why post-mortem research of cetaceans is such an important field of research, as you will not be able to do the same with live animals. It allows us to zoom in on a species and learn much without using invasive techniques on a live animal.
How to get involved?
Performing cetacean necropsies requires extensive and proper training, as mentioned earlier. It’s also not without its risks, as you can expose yourself to diseases, and you have to wield very sharp knives to dissect the animal. Additionally, you’re working with thousands of kilos when working on larger whales. If you encounter a stranded or deceased individual, immediately contact the authorities and do not touch the animal. We have a whole post dedicated to what you can do in this situation.
There are many stranding research organizations around the world. If you are interested in this field of study, don’t hesitate to locate and contact an organization. The people working in this field are more than happy to tell you all about the process of cetacean necropsies. If you’re lucky, you might even receive an invitation to watch one! If you happen to live near the beach, you could also check out if you can join the local stranding volunteers who collect the cetaceans for research. The International Whaling Commission has an extensive list on its webpage with stranding networks all around the world.
Here are a few of them:
- Netherlands: https://www.uu.nl/en/research/strandings-investigation
- Scotland: https://strandings.org/
- Australia: https://amru.org.au/our-research/marine-mammal-health/
- USA: https://cascadiaresearch.org/project/stranding-response/
- Canada: https://marineanimals.ca/what-we-do/stranding-and-response/
Lastly, contacting stranding organizations for internships is also a way of getting into this field of study. We have a post dedicated to finding internships here.
This article was created in collaboration with Utrecht University: You can find their website on stranding research here.
Eva Schotanus is a Coastal and Marine Management student from the Netherlands, where she specialized in marine biology and cetacean necropsies. She's currently working on finishing up her Bachelor's by studying the nutritional condition of stranded harbour porpoises in the North Sea at Utrecht University.