Story of a stranded pygmy sperm whale - WARNING: GRAPHIC PHOTOS

WARNING: This post includes graphic photographs of a deceased pygmy sperm whale. This post may not be appropriate for everyone so please proceed with caution or skip this blog.

Hi all,
Deceased animals are a common part of our work in the Stranding Department. There are many reasons an animal may wash up dead or die on the beach. Natural causes such as old age, failure to thrive for a pup or a calf, disease, human interaction such as encounters with fishing materials or ship strikes, and predation by other marine species. This list is by no means complete, it is a short list to reinforce the concept that, like people, animals die too.

It is important to perform a necropsy (animal autopsy) on marine mammals and sea turtles to try to determine the cause of death. The longer the animal has been dead the more difficult this task becomes. As an authorized marine mammal responder on behalf of the National Marine Fisheries Service (NMFS) we are obligated to collect a certain set of data depending on the condition of the animal when found.

So, on to the story of the pygmy sperm whale ... this animal was found dead in the surf in Winthrop, Mass. on Monday night. I'll start you off with a distant photo so you can test your stomach for this sort of thing.

In the image below, the Department of Conservation and Recreation relocates the animal to a beach were we can conduct a necropsy examination and then bury the animal deeper the 6 feet. Pygmy sperm whales, (Kogia breviceps) are fairly rare north of Cape Cod, however we do see them from time to time.

Species identification, age class, gender, condition of the animal, and measurements are of the utmost importance. When this pygmy sperm whale washed ashore, it had been dead for a few days at least. Most of the skin was missing and the eyes were sunken in. With the skin missing, most of the obvious field markings were gone. To determine exact species of an animal in this condition it is best to look at the overall size, shape and location of the dorsal fin, shape of the mouth and the the shape, location and number of teeth. Pygmy sperm whales have a small narrow lower jaw with long sharp curved teeth located only in the lower jaw.

In this photo, I examine the teeth for shape size and location to confirm that this animal is a pygmy sperm whale. Pygmy sperm whales can often be confused with dwarf sperm whales which, look almost exactly alike.

This photo shows the animal in the surf before we removed it from the water. As you can see most of the skin is missing with the exception of the long black patch. Note how far back the dorsal fin is located ont his animal, this is one of the distinguishing characteristics between the pygmy and dwarf sperm whales.

We completed a detailed external examination of the animal before we began the dissection or necropsy. We found a linear (straight line) scar (one of several). This is a sign that this animal had some sort of encounter with a made-made object. The technical term for this finding is called evidence of Human Interaction. 

I decided not to include any photos of this animal once we began making our cuts to enter the body cavity. I'll explain here that we examined all the organs and the tissues under all the scars. The dissection of this animal took several hours. While we had the help of three interns, Adam and I did all the cutting and organ examinations. We learned a great deal from this animal and wish to thank the animal control officer in Winthrop, all members of the harbor master's office in the town of Winthrop, the staff from the Department of Conservation and Recreation, and the Massachusetts Environmental Police for helping secure this animal and providing support for us to perform this important necropsy.


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