The Wildlife Disease Laboratories of the San Diego Zoo Institute for Conservation Research and the San Diego Natural History Museum (SDNHM) have had a long-time working relationship. So when Scott Tremor, the mammologist at SDNHM and a long-time friend of mine, called me in March to tell me about his latest adventure and make an interesting proposition, we were intrigued. A 30-foot-long juvenile humpback whale had died, and the carcass had washed ashore at Pelican Point, on the tip of Point Loma. Humpback whales are relatively rare off San Diego’s coastline, so the museum wanted to preserve the specimen for its collection. It had laid on the beach in the sun for over a month, and Scott was collecting volunteers to help clean the bones.
Having never necropsied a whale and being unfamiliar with the anatomy, I thought it would an amazing experience. This rare opportunity also enticed a few coworkers and two pathologists (Dr. Jenny Bernard, Dr. Andrew Cartocetti, Megan Varney, and Rachael Keeler) to put on their Tyvek® suits and boots and help out. With the warning that the carcass may have washed away overnight and may not be there when we arrived, we met up with other volunteers at the San Diego Natural History Museum and headed to the beach.
Pelican Point is a relatively narrow beach surrounded by a high cliff. This beautiful spot, part of Cabrillo National Monument, is closed to the public—the only way to reach it is down a cliff wall using a knotted rope. We timed our excursion to coincide with low tide, so we could access the beach and the whale. There, we were met by Southwest Fisheries Science Center employees, who are responsible for testing tissues and collecting measurements on all beached cetaceans. Dr. Thomas Deméré, curator of paleontology at the SDNHM, led us through the process. One of his areas of expertise and interest is in the evolutionary history of baleen whales, also known as the mysticetes. He explained that baleen species (humpback, fin, blue, minke, right, and grey whales) are filter feeders, but have all evolved different feeding strategies. Fossil evidence shows that all baleen species evolved from toothed whales. In studying today’s mysticetes , scientists have discovered that baleen whale embryos develop upper and lower teeth that simply never erupt. At some point the teeth are reabsorbed and baleen is formed. Because baleen is made of keratin, it rarely fossilizes and has not been studied much—making it important on this excursion to comb the beach in search of the sloughed baleen in addition to recovering the whale’s bones.
When we arrived, the whale looked like a white-grey mound. The goal of the day was to disarticulate the skull from the body and move it to the base of the cliff. Naturally, the tide washing over the carcass had removed some of the flesh exposing some bone, but there was still a lot of work to be done. The soft, rubbery flesh was hard to cut through and the sand dulled our knives immediately. Tom was amazing at directing us the best way to maneuver the skull so we could cut away the muscles. In the end, the strength and endurance of so many people accomplished our goal; we separated and lifted the 300-pound skull to a safe place on nearby rocks. All the while, a pleasant breeze of fresh ocean air kept the smell away. It wasn’t until later in the car ride home we realized we smelled like the hold of a fishing boat!
As you would expect, Scott and his volunteers made many more trips to the beach to recover as many bones as possible, stacking them at the base of the cliff. On April 14, the skull was placed in a sling, and the U.S. Coast Guard airlifted it first to a nearby parking lot, then on to a spot where it was buried so local insects could finish cleaning the bones. All of the other bones were carefully moved assembly-line style by a group of volunteers. It was front-page news in the local media that day! What a great opportunity we had collaborating with our neighbors at the San Diego Natural History Museum to turn a tragedy into valuable learning experience.
April Gorrow is a senior pathology technician at the San Diego Zoo Institute for Conservation Research. Read her previous blog, Nature’s Excellent Engineering Feat: The Egg.