For decades, the U.S. Navy Marine Mammal Program in San Diego has provided cutting-edge veterinary care to bottle-nosed dolphins and California sea lions.
The Navy uses these animals to find and mark the location of underwater objects. Both of these marine mammal species can be trained to perform a variety of tasks for the Navy. They are fast and agile swimmers, can dive up to 1,000 feet underwater, and can do repetitive dives without suffering from the bends.
The program’s animal care team comprises members of the U.S. Army Veterinary Corps, civilians, National Marine Mammal Foundation veterinarians, and other animal health care experts. Together, the marine mammal veterinarians who care for the program’s 80 dolphins and 40 sea lions constitute the largest group of marine mammal veterinarians in the country.
Dr. Cynthia R. Smith, executive director of the NMMF, explained that marine mammal veterinarians from the program originally created the nonprofit foundation under Dr. Sam Ridgway’s guidance (see sidebar, page 872). The NMMF currently provides medical care for the Navy animals and clinical research support that helps the Navy continuously advance the health and welfare of its marine mammal population.
Three Army veterinarians and five Army veterinary technicians represent the Army Veterinary Corps in the program. Because this is a unique assignment, the Army staff members undergo a lot of on-the-job training as part of the veterinary care team.
Capt. Lara S. Cotte, officer in charge of clinical veterinary services, concedes there is a steep learning curve for new Army personnel who rotate in.
An ounce of prevention
Veterinarians with the program place a heavy emphasis on preventive medicine and routine diagnostic testing, but also stress maintaining social and environmental conditions that keep their animals healthy.
The Navy’s marine mammals go through an annual wellness examination, which includes a history and physical examination, auscultation, and collection of fecal and blood samples. Animals are dewormed every six months, and sea lions receive monthly heartworm preventive.
Sonographic and endoscopic examinations are a routine part of the preventive medicine program, and on occasion, the veterinary staff perform CT or MRI scans at the nearby Naval Medical Center in San Diego to better characterize the animals’ health.
Trainers are taught the signs to look for when performing medical checks every day and whom to notify when something isn’t right, whether it’s a low appetite or change in behavior, Dr. Cotte said.
“One of the biggest problems working with marine mammals is they are incredibly sophisticated at masking disease,” which requires looking for subtle cues, she said.
While the Navy marine mammal population has consistently had low mortality and high survival rates over the past 20 years, illnesses are inevitable in any animal population. The most common health issue for the sea lions is mild gastrointestinal disease, which is likely also the case for their counterparts in the wild. In the dolphins, Dr. Cotte said, respiratory conditions such as bronchopneumonia are the most common illnesses.
As the number of geriatric animals in the Navy’s marine mammal population has increased, so has the prevalence of age-associated diseases, including arthritis and cataracts, according to Dr. Eric D. Jensen, managing veterinarian for the program.
Dr. Jensen said that along with the increase in the number of older animals have come conditions they’ve never seen before in marine mammals, such as neoplastic disease.
“They were really rarely reported when I first started working with them. Now we’re seeing organ system failures like heart failure, kidney issues, liver issues. A lot of those changes are just associated with old age and degeneration,” he said.
“Our understanding of how long dolphins live in the wild is evolving, too. And our population is doing very well. We have lots of animals in their 30s and 40s and occasionally 50s.”
Male sea lions in the program live about triple the years they would in the wild, reaching somewhere in their mid-20s or older.
Each animal at the program is trained in husbandry behaviors to facilitate their health care. Dolphins are trained to accept a tube inserted into their stomach to enable veterinarians to monitor gastric health with fluid sampling and gastroscopy as needed. The dolphins are also trained to allow veterinarians to perform physical examinations in the water, including temperature monitoring, fecal sampling, blowhole swab sampling, and ultrasound examinations. Recently, they’ve been taught to allow urinary catheterization while they are still in the water, so researchers can collect urine for a renal study.
This training has been an important part of the program since its inception, as a result of the work of one of the program’s founders, Dr. Ridgway, who is now senior scientist for animal care and research with the foundation. In fact, it was the conflict between Dr. Ridgway’s need to gain access to an animal to obtain health information and a trainer’s need to continue with training activities that led to the development of one of the earliest voluntary husbandry behaviors in marine mammals.
Dr. Ridgway explained, “Dr. C. Scott Johnson, who was a physicist working on dolphin hearing at the time, was annoyed by my upsetting his training once a month, taking a blood sample. So he trained his animal to present its tail fluke so I could take a blood sample and to roll over and open his mouth. We could do a whole physical exam with the cooperation of the animal and do it in the water.”
||The program has more than 200 trainers, who often go through a three- to four-month internship program out of college and then get hired. (Photo by Malinda Larkin)
At the time—the late ’50s and early ’60s—a lot of seminal research on animal behavior was being published. B.F. Skinner, PhD, published his landmark paper “How to Teach Animals” in 1951 in Scientific American, introducing the term “shaping” and the use of a clicker as a conditioned reinforcer.
To learn how to better train the animals, Dr. Ridgway and others were taught the details of operant conditioning by a graduate student of Dr. Skinner’s, Keller Breland.
Mark Xitco, PhD, head of the scientific and veterinary support branch of the Navy program, said the notion that animals could be trained to participate in and facilitate their own health care became ubiquitous in the marine mammal community and then spread as marine mammal trainers infiltrated the larger zoological community.
“Now everywhere you go—to zoos and aquariums across the world—there (are) hundreds of species sitting still for blood samples. It all started with Sam and Scott over the tension disrupting his audiology research because Sam wanted a sample. They came to such a productive solution,” Dr. Xitco said.
Wealth of information
Another unique aspect of the program that allows for quality animal health care is its database, which has the most inclusive data sets in the marine mammal world, Dr. Cotte said.
Dr. Jensen recalls his first months with the program and being amazed at the depth of information available on each animal.
“I’d look on a sheet (for a particular animal), and they had 25 previous (bloodwork reports). I mean, people don’t even have that,” he said.
The program has kept electronic records since the mid-1990s. The information includes results of laboratory and other tests, diets, medications, and travel data. It takes a staff of five full-time employees to maintain the database for health care and research purposes and preserve the program’s archive of samples.
The program archives tissues and other biological samples from all animals in the program. These samples fill about 10 freezers and date to the beginning of the program.
“The advantage of the archive is if we have a question and there’s something we want to go and look at, say if animals in the past had a virus or disease, we can pull samples, test, and see if there’s something that could help us answer a question,” said Capt. Kamala Rapp-Santos, an attending veterinarian with the program.
||Dr. Sam Ridgway (TEX ’60) has been called the founder of marine mammal medicine. The former U.S. Air Force veterinary officer joined the U.S. Navy Marine Mammal Program in 1962, two years after it was started at Point Mugu, a missile base on the California coast. He’s now president of the National Marine Mammal Foundation as well as a senior scientist with the Navy program. (Courtesy of U.S. Navy Marine Mammal Program)
Fostering the future
Not only are the record keeping and veterinary care done in-house, but also, so is the breeding of animals.
The first animal was born in the facility in 1973. Before then, dolphins were caught either from the Gulf of Mexico or the Atlantic Ocean. The older sea lions were wild-caught on local beaches, but the more recent ones come from rehabilitation facilities with animals that are deemed nonreleasable.
All the sea lions in the program are neutered males. Dr. Rapp-Santos said that’s to prevent aggression and protect them against related injuries as well as reproductive diseases.
Dr. Ridgway said they started the dolphin breeding program with the thought that perhaps animals bred for certain traits could be trained more quickly, but said it hasn’t been long enough to determine whether this works.
A unique health challenge from the breeding program emerged in 1977 when the breeding program was started in earnest. Not many people had handled baby dolphins before then.
“It’s only been the last 10 to 15 years that the industry—not just us but places like Dolphin Quest and others—have found ways to safely handle babies so that they could really elevate their neonatal care programs, and that’s had a huge positive impact on calf survival rates,” Dr. Jensen said.
Citing publications that estimate calf survival rates in the wild at around 50 percent, he said, “I know for a lot of institutions that our survival rates are significantly higher than that, and it has everything to do with wellness exams and if they’re showing signs of infection, getting an early start on it.”
Dr. Rapp-Santos explained that dolphins spend their first two years learning basic behaviors and getting acclimated to humans. Then they are considered part of the pipeline, their equivalent of grade school.
Around age 9 or 10, dolphins that pass a certification process graduate as full-fleet animals. Trainers decide what system each animal is best-suited for. The others still have a place; they are considered “spares” to be deployed as backups.
Outside researchers can request samples from the database of the U.S. Navy Marine Mammal Program. The program has fluid and tissue samples from decades ago.