When Asian elephant Swarna needed her teeth examined, animal keepers Rebecca Riley and Becca Spickler tried something that had never been done at the Smithsonian’s National Zoo before. Over two months, they trained the 44-year-old elephant to voluntarily participate in dental radiographs! Get the scoop on this breakthrough in our keeper Q&A.
Swarna explores one of the outdoor yards of the Elephant Trails exhibit.
How many teeth do elephants have?
Riley: An elephant has four brick-sized molars (one in each quadrant of the jaw) and two modified incisors (tusks) that protrude from a pocket on either side of the trunk. The number of teeth does not vary between male and female elephants, or between the species. Male and female African elephants and Asian male elephants all often have very large tusks, while Asian females have very small tusks, called tushes, which typically are not visible.
An elephant has six sets of molars throughout their life. As each tooth is worn down, the front pieces break away and the next tooth pushes forward—like a conveyor belt. An elephant often goes through its first three sets as a juvenile, leaving the final three sets to last the remainder of its life.
Animal keepers train the Zoo's elephants to open their mouths. This enables keepers to check for any dental issues that need to be addressed by veterinarians.
What prompted you to train Swarna for dental radiographs?
Spickler: Examining our elephants’ teeth is a routine part of our daily health checks. We look for any redness, swelling, sharp edges and changes in the wear pattern. We also watch for changes in their eating patterns. For example, does an elephant favor chewing on one side of its mouth?
Swarna’s tooth exams showed an unusual shape and wear pattern on her teeth, especially on the right side. We have been documenting the changes to her teeth by taking photos every six months since she joined our herd in May 2014. Tooth exams are also a routine part of every elephant’s annual veterinary exam, so our vets have also been watching these changes to Swarna’s teeth as well.
During her most recent annual vet exam, the vets asked if they could try to take tooth radiographs. This is not a routine procedure for elephants due to the sheer size of their skulls and teeth. We were not sure if it would be possible to get quality images of an elephant’s teeth. But knowing Swarna, we knew we could try.
Asian elephants Maharani (L), Kamala (M) and Swarna (R) nosh on some browse at the Elephant Trails habitat.
What is Swarna’s personality like?
Riley: When Swarna has a trusting relationship and confidence in her trainer, she is motivated and eager to learn. At times, she can be timid or anxious in new situations, or when there are novel items in her environment. She may also stop participating in training sessions if she is feeling confused or frustrated. However, knowing her so well means that I can anticipate issues that affect her confidence, help her work through them and have a successful training session.
Swarna’s personality is actually very much like my own. I think that is one of the reasons we have such a strong relationship. It often feels like we have put our faith in one another, and together, we can overcome any challenges we choose to take on.
Animal keeper Becca Spickler trains Swarna to rest her trunk on the crossbeam of her enclosure.
How did you train this behavior?
Riley: We use operant conditioning to train our elephants. That means the elephants have the choice to voluntarily participate in training or choose to spend their time doing other things. The first step is asking Swarna to lift her trunk and rest it on a crossbeam in her enclosure. That way, she can keep it elevated for longer periods and comfortably remain still.
Then, we ask her to open her mouth so we can see her upper teeth clearly. While this is not necessary for the images, we found it gives her something to focus on and allows the vets see where the radiograph machine is aimed.
Once she was comfortable with the two primary behaviors, we began desensitizing her to the mock equipment. A digital radiograph detection plate had to be placed against her cheek, and the portable radiograph generator had to be lifted into place. We needed her to acclimate to this because all three aspects—the plate, the generator and the elephant—need to be perfectly still to capture an image.
Keeper Rebecca Riley (L) holds a dental plate steady while keeper Becca Spickler (R) asks Swarna to remain in place.
What is Swarna’s reward for participating?
Spickler: If Swarna chooses to participate, she receives positive reinforcement in the form of her favorite foods: large chunks of produce like apples, carrots, sweet potatoes and pears cut in half. We also give her lots of verbal praise to build her confidence and trust in us.
How long did it take Swarna to master this training?
Riley: We began training the trunk up/open mouth behavior on the crossbeam in early November 2018. It took about five or six training sessions over two weeks for her to figure out what behaviors we were asking her to do.
The following six weeks, we practiced two-to-three times per week focusing on duration, repositioning, repetition, mock equipment and getting comfortable with having more people in the vicinity. Now, we practice once a week to maintain the behavior.
Animal keeper Rebecca Riley (R) tries holding the dental plate at another angle while keeper Becca Spickler (L) asks Swarna to stay in place.
Did you have to overcome any challenges?
Spickler: Elephant tooth radiographs are not common due to the size of the skull, so there is not an established technique for taking them. Alongside our vet team, we have been making repeated adjustments in position, angle and beam strength to capture the images we need.
Swarna’s training included these repetitive movements, making slight variations in position each time. We wanted to ensure she knew what to expect and did not think she was doing the behavior incorrectly. Even after one successful radiograph session, we continue to work on perfecting the technique with our vet team and will maintain routine training to get it right.
Why is voluntary participation key to the Zoo’s training program?
Riley: It is incredibly important that our elephants have the choice to participate in their own husbandry and medical care. Their size alone prevents us from transporting them to the veterinary hospital, so our vets (and medical equipment) come to the elephants. We want to make these procedures as positive and stress-free an experience as possible. By making every procedure a normal part of their training routine, we have calmer elephants, safer procedures and better results.
For example, when an elephant requires a tooth radiograph, it is common practice to put him or her under anesthesia. Elephants face an increased risk of complications due to their weight, which places pressure on their internal organs while they lay in the prone position. Training them to voluntarily participate in awake radiographs eliminates the need for anesthesia.
Animal keepers Becca Spickler (L) and Rebecca Riley (R) successfully trained Swarna (M) to voluntarily participate in dental radiograph training.
How can this training help elephants?
Spickler: Although we look for anything that might be ‘off’ health-wise during our daily husbandry training sessions, this could be an invaluable diagnostic tool for seeing issues that lie under the surface. In the long term, it helps us get ahead of geriatric issues that our elephants may have as they get older.
If we are able to perfect the radiograph technique with Swarna, there is great potential to train our other elephants to voluntarily participate as well. Beyond the Smithsonian’s National Zoo, aging elephants in zoos across the country inevitably will be challenged with geriatric issues. We would love to share our training plans, facility modifications and radiograph techniques with other zoos to benefit their herds. Sharing information about diseases and treatment options is beneficial for the population in human care as a whole and contributes to our mission of saving species.
How does it make you feel that you helped Swarna accomplish this training?
Riley: I am so incredibly proud of Swarna for successfully participating in radiograph training. Much of it comes from knowing she trusts me to introduce new situations and be by her side as she faces these challenges head on.
Spickler: I am newer to the Swarna team. For me, it was truly the first time I felt like she trusted me. She participated the entire time, even with lots of stimuli around her. Being able to see our hard work in put into practice made me proud of what all three of us were able to accomplish together.
This story appears in the March 2019 issue of National Zoo News. See elephant care and training in action at the elephant keeper talks at 11 a.m. and 2 p.m. daily. Learn more about animal enrichment and training at the Zoo here.