When you hear or read the term "marine mammal," chances are you think immediately of a sleek dolphin, or a graceful whale. But not all marine mammals are of the hairless variety. Sea otters, like the five we have here at Shedd Aquarium in fact, set the record for hairiness! Sea otters have more hairs per square inch on their body surface than any other known animal.
Their hair is one of the amazing ways they have adapted to living in the cold ocean waters where they are found. Many other characteristics contribute to the remarkable nature of otters, and as the head veterinarian charged with their care at Shedd, I often get questions about them and what it is like to work with them as patients in my care.
With Sea Otter Awareness Week upon us, I think it's a fantastic time to talk about what goes into keeping these adorable and small (well, relatively small, they can grow up to 90 pounds!) animals healthy.
What sort of patients are otters? How do they receive a physical examination? What sorts of tests do you do and what do the results reveal?
When sea otters are babies, especially like the rescues at Shedd, they require almost constant assistance and are somewhat able to be handled by their caretakers without much special equipment or uniforms.
But that changes fast. As soon as they start taking solid foods, they start using their formidable teeth and aren't afraid to use them. They have very strong jaws and teeth adapted for cracking open shellfish, clams and urchins.
So, when we need to examine a sea otter, we take careful precautions when handling them. Then comes a thorough full body inspection. We listen to their heart, lungs and gastro-intestinal sounds with a stethoscope, feel for masses or asymmetry in their abdomens, any evidence of arthritis in their joints and anything else that may feel out of the ordinary.
We will usually also take blood samples or use X-rays to take images of internal organs. These tools give us huge amounts of valuable information about how their organs are working.
What are key take-aways and common findings from the examinations?
Most often our animals get a 'clean bill of health' after their routine assessments. However, on occasion, we will find things like mites that like to live in their noses. These are very common in otters, and almost every wild otter is home to a population of these mites.
As the animals age we also often see tartar accumulating on their teeth, and they need to have them cleaned and polished just like a dental hygienist does for a human's teeth! We sometimes see other age related issues from time-to-time, like cataracts or tumors.
The information we are able to gain from lab tests done on the blood samples we collect is very helpful to biologists in the field that are focused on understanding otter health and the impacts of environmental change on otter health. Many of our otters have contributed to studies comparing gene function of otters in the wild affected by becoming covered in oil to animals in human care that are genetically related but have never been exposed to oil. These important studies can only be done by carefully evaluating animals in our care and have resulted in multiple scientific publications advancing our understanding of what it takes to care for these animals wherever they live.
[For those interested, see for example Bowen et al., (including Van Bonn) 2012. Gene transcription in sea otters (Enhydra lutris); development of a diagnostic tool for sea otter and ecosystem health. Molecular Ecology Resources Vol. 12 pp. 67-74]
We've heard that orphan baby otters require 24-hour care. Why is that and what does it look like?
It's true, when rescued otters are very young and should still be nursing milk from their mothers, they require round-the-clock care when they arrive at Shedd. This is because in nature they nurse almost non-stop! It's the same for orphaned otters. Otters have very high metabolic rates which means they burn a lot of calories very quickly. Burning calories produces heat, which is another way otters stay warm in the cold oceans. The quickly growing baby otters mean they need to burn even more calories, which means feeding them often.
When still sucklings at Shedd, they receive a milk replacement designed to mimic mother's milk. As they get older they will then slowly transition to solid foods like clams, crabs, shrimps and urchins.
Orphaned otters also take a while to figure out how to care for their specialized coats of hair. In the wild, mothers help clean and condition the baby's fur by grooming them as they ride on mom's belly. Here at the aquarium, our trainers serve as surrogate moms, and do the grooming and conditioning which also requires around-the-clock care.
Once in a while, like any new baby, we might see one get a little colicky and gassy, and may require a little anti-gas medication which usually takes care of it. And fortunately, there are no diapers to change!
How can I learn more about sea otters living at Shedd and in the wild?
While animals in human care help us learn so much about the species, there is plenty more to be done to care for otters in the wild. During Sea Otter Awareness Week, it's vital to note the threats faced by sea otters on the west coast, particularly those caused by warming ocean temperatures that are a result of El Nino. While Shedd has dedicated resources toward rescue and rehab in that area, there is plenty everyone can do to keep their populations from further threats, which you can read about here.
Bill Van Bonn, DVM, is Shedd Aquarium's vice president of animal health. With more than 25 years of clinical veterinary experience, Dr. Van Bonn strengthens the aquarium's established animal care and health expertise, overseeing its diverse aquatic medicine initiatives as well as furthering innovative veterinary science at Shedd. Dr. Van Bonn specializes in preventive medicine and enhanced clinical veterinary services for aquatic animals, with a focus on marine mammals. At Shedd, he focuses on providing top-quality care and applying his knowledge of animal health to conservation of their counterparts in the wild. He also oversees the aquarium's Microbiome Project.