At the end of April, the San Diego Zoo mourned the passing of probably its oldest mammal resident. He arrived here in 1956 and was believed to be more than 58 years old at the time of his death. Was he a great ape? An elephant? A rhinoceros? None of the above. Victor was a short-nosed echidna, a spiny, egg-laying mammal (called a monotreme) from Australia about the size of a large housecat. In his years in our Children’s Zoo, Victor touched (or at least was touched by!) thousands of visitors fascinated by this unusual and amazing creature. His death may have ended his long career as an animal ambassador, but even after death, Victor continues to be a source of important information and learning.
Part of our job in the Wildlife Disease Laboratories is to help ensure the health and well-being of the animals in our care. But no matter how well we do our job, all animals eventually reach the end of their natural lifespan, be it 6 years or 60. When this happens, we try to make the most of a difficult situation by turning it into an opportunity to share and to learn. What we learn from our animals after they die is very important and helps our living collection. We are keeping the live animals alive by learning from them after they pass away. Learning and sharing knowledge is a key role we play in the circle of life.
When Victor died, his body came to us. We performed the animal version of an autopsy, called a necropsy, to look for disease and determine his cause of death. How do we do this? Well, if you’ve seen an episode of CSI or Bones, you probably have some idea, but the lesions of natural disease are different, and recognizing them depends first and foremost on knowing what is normal. As you can imagine, in our line of work, with the large diversity of animals we see, “normal” is relative! With their narrow, toothless beaks, lack of external ear flaps, internal testicles, and single opening for urogenital and digestive tracts (called a cloaca), normal for an echidna is certainly abnormal for most other mammals. In fact, it sounds more like a bird!
Never having seen the inside of an echidna, we relied on knowledge of the species, published information, and years of experience with other animals to separate abnormalities related to disease from normal anatomy. Luckily for us, there are generally more similarities than differences, and a disease in one species often looks the same in another. Ultimately, Victor’s problem, like many older primates and dogs, was his heart. A large, dilated heart with white streaks of scar tissue in its muscle points to heart disease in any animal. Victor had been undergoing treatment for heart failure when he died, and the necropsy findings confirmed the clinical diagnosis.
While this information about one animal might not seem like much, over time, with thorough documentation, knowledge of the common diseases in echidnas will help zoos screen their animals for these diseases and initiate treatment earlier. Tissues preserved from Victor on glass slides are now part of a museum-quality archive that can be used for future studies. Additional tissue samples went to other research divisions at the San Diego Zoo Institute for Conservation Research, where these precious specimens could provide important insights in the fields of genetics and reproductive physiology. His body was donated to a museum to be a source of learning and enjoyment for future generations.
Our collections are a finite and irreplaceable treasure of biodiversity, which is why we collect, conserve, and share biomaterials in support of nonprofit research that furthers our conservation and education mission. In this way, Victor lives on!
April Gorow is a research coordinator and Rachel Burns is the Steel Endowed Pathology Fellow, Wildlife Disease Laboratories, San Diego Zoo Institute for Conservation Research.