Mena is an important ambassador for her species and her team at the Virginia Aquarium continues to learn more about who she is through their important behavioral work and enrichment with her.
If you have visited our Red Sea Aquarium tunnel, chances are you have seen Mena, our beautiful, docile resident zebra shark resting on the sandy floor of her habitat or swimming overhead. She is a remarkable favorite with guests, and in the more than ten years since her arrival in 2011, her caregivers have endeavored to learn as much as they can about her and how best to enrich her life.
Mena hails from the waters off the northwest coast of the Indonesian island of Java, near the capital city, Jakarta and today she is thought to be around 12 years old. She is an important participant in the StAR (Stegostoma tigrinum Augmentation and Recovery) Project and scientists hope she will aid in the repopulation and genetic diversity of endangered zebra shark populations. We hope to share more about the StAR Project in a future post but for now, let’s talk more about Mena and just how special she is to us.
At 6 feet in length and weighing 80lbs, Mena enjoys a balanced diet that includes a variety of restaurant-quality shrimp, squid, conch, capelin, herring, and smelt. Her personal favorite is the special menu on Tuesdays and Fridays when she receives the “Fish of the Day,” which includes either salmon, Boston or Spanish mackerel, bluefish, cod, or rockfish. Mena is fed only once a day, and her diet is carefully calculated to ensure she receives the appropriate number of calories. Managing her diet is imperative since food rewards are used in her training sessions, and this behavioral work is important to her care and the safety of her caregivers.
Mena has demonstrated incredible progress over the years in her training sessions, especially target training. Target work is done with many of the resident Aquarium animals. It involves asking the animal to touch a specific object or location and when they succeed, they are rewarded, usually with food. Target training helps to focus Mena’s attention and allows the caregivers to ask Mena to go to a certain location in her enclosure. This allows them to directly feed her and so be able to better monitor her diet.
Building on behaviors and skills previously mastered by Mena, her training plan was renovated, and she continues to demonstrate great progress. The current goal is to have Mena willingly display these new behaviors in hopes that our veterinary staff will be able to carry out procedures like drawing blood or performing an ultrasound while minimizing Mena’s stress and increasing the safety of the staff.
For example, while Mena already responded to a request to touch a stationary target in a familiar location, her caregivers challenged her to respond to targets throughout the exhibit and even to follow the target as it is moved throughout the water column. This willingness to target anywhere and even follow a moving target will allow staff to move her onto a stretcher or into a hospital enclosure with less stress. The staff even added in hand-signal cues as they worked to teach her to approach them.
Once Mena was comfortable approaching them on cue, the staff added tactile training, which included stroking her as she swam by to receive food. The goal was to have her comfortable with human touch and eventually have her comfortable enough to willingly allow veterinary staff to roll her over into what is called tonic immobility (TI).
While this state is not fully understood, some sharks go into TI, a trans-like state of rest, when rolled over onto their backs. Some shark species do it to a lesser degree than others, and scientists do not assume that TI will be displayed by all shark species. However, zebra sharks, when rolled onto their backs, appear to relax, though they also seem to remain aware of what is happening around them and to them. Naturally, if Mena will voluntarily roll onto her back and relax, exams and procedures like blood draws can be far less stressful for her and everyone involved.
In addition to behavioral training, which certainly facilitates Mena’s mental development, she is challenged with other enrichment in the form of toys and play. Caregivers might feed her with a food tube, or they might place some of her favorite snacks inside a “jolly ball” (a virtually indestructible toy from Jolly Pets®). To access the food Mena must manipulate the item until the treat is released, accessed, or falls out, and then she is rewarded with the treat. For those of you with dogs, it is very similar to putting a kibble or some peanut butter inside a Kong® toy. While it would be easy to see enrichment as just a fancy word for playtime with toys, and while we do want her enrichment to be enjoyable, the goal is to grow her brain. We hope to challenge her to think like her counterparts in the ocean must think to find food and navigate their environment. We do want enrichment to be fun for Mena, but more importantly, we hope to stimulate her mind.
We know that sharks are often burdened with an unfair reputation, but we are finding that we have so much yet to learn about these amazing animals. Mena has been an invaluable representation of what sharks are capable of and why we must do our part to help conserve them. Her caregivers here at the Aquarium continue to appreciate Mena for all she is learning and what they are learning in the process.
We hope you will take time to visit us at the Virginia Aquarium and by all means, be sure to visit Mena!
You can learn more about zebra sharks on our website