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Diapers for Dermatemys

by Jordan Gray

It was the Spring semester of 2015 and Nichole Bishop, now a PhD candidate in the University of Florida’s School of Natural Resources and Environment, wasn’t exactly sure what organism she would focus on for her dissertation in Nutritional Ecology. Although she had always been fascinated by turtles and tortoises, the second-semester student hadn’t yet narrowed one down that was fully herbivorous and would meet her research needs. Then late one Saturday night, her advisor, Dr. Ray Carthy, sent her a text message: “How much do you know about the Hicatee?”. She wasn’t aware at the time, but this perplexing question would soon take her on regular adventures deep into the tropical forests of Belize.

The Central American River Turtle (Dermatemys mawii) commonly called “Hicatee” in their Central American range is one of the most enigmatic turtles on Earth. Found in the rivers, oxbows, and flooded forests of Southern Mexico, Northern Guatemala, and Belize, the Critically Endangered Hicatee is the only surviving member of its genus and the family Dermatemydidae. A fully aquatic and fully herbivorous species, the Hicatee not only provided Nichole a perfect species for her graduate research, but also a species in which her research may help current and future conservation efforts for.

Among the questions Nichole hoped to answer are, 1) What do they eat? 2) What food preference is seen across the age classes? 3) What nutrients are being utilized? These questions can help improve the nutritional component of the husbandry the Hicatees receive in the captive assurance colony for the species at the Hicatee Conservation and Research Center (HCRC), a collaborative between the Turtle Survival Alliance and the Belize Foundation for Research and Environmental Education (BFREE). More importantly, improved nutrition can potentially help maximize the reproductive fecundity of the adults at BFREE. With 57 Hicatee at her disposal, Nichole has the largest captive population of Hicatee from which to retrieve data on the turtle’s feeding habits and nutritional needs. Understanding what food items make up the primary components of the diet of the various age and sex classes will be instrumental in the captive-breeding, rearing, and long-term maintenance of the Hicatees at the HCRC.

This past Spring, Nichole made her 7th trip to the HCRC to gain more valuable data on the feeding habits and nutritional absorption of adult and young Hicatees. To perform their current phase of the research, Nichole and her colleagues had to devise a way to catch all the fecal excrement without it separating into the holding pools. Although they had developed a prototype for their “Hicatee diaper” at the University of Florida, a whole innovative design needed to be “jerry-rigged” on site after the prototype proved ineffective. Utilizing old t-shirts and duct-tape, Nichole and her colleagues successfully made a new diaper that would effectively catch the fecal matter, while providing normal locomotion in the water. Nichole was kind enough to share her journal entries from the trip below!

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Nichole Bishop: My research focuses on the nutritional ecology of the Hicatee. One of the objectives of my work is to understand how the Hicatee processes nutrients. To study this, I need to quantify the amount of food eaten vs the amount of fecal matter excreted. Because all the fecal matter must be accounted for, nutritional ecologists use “diapers” when conducting these types of studies. Back in the States, I had developed a diaper prototype for the Hicatee, but my design was limited because I had no Hicatees on which to fit my design! My “model” was a rubber cast of a Green Turtle (Chelonia mydas), which was better than nothing. I left for Belize on Thursday, February 23rd, ready to put our experimental diaper to the test!

Thursday, February 23rd ‚Äì We arrived at the only international airport in Belize located in Belize City. From here, we hopped on a puddle jumper (seats about 10 people uncomfortably) for the hour-long flight south to the city of Independence. In Independence, we coincidentally ran into one of the employees from the Belize Foundation for Research and Environmental Education (BFREE), (where the Hicatee Conservation Research Center is located). He was in town picking up supplies and offered us a ride back to the center with him so we didn’t have to catch a taxi. We gladly accepted the ride and headed southwest on the Southern Highway. After an hour or so, we had to switch vehicles because we had reached the point where we must go off-road. We picked up the 4-wheel drive truck and drove the 6-mile “road” into the jungle. It had recently rained and knee-deep “puddles” covered large expanses of the road. On other trips, we have had to hike in to the BFREE because the road was impassable by vehicle. The road dead-ends into a river, at which point we hopped into a canoe and paddled across to the field station at BFREE.

Friday, February 24th ‚Äì We started early in the morning because we had to catch adult males from the HCRC’s ponds (they have two ponds that house their captive adult population) to use for the study. Using a seine net, we entered the water and wrapped the net along the side of the pond and passed it across the pond to catch the Hicatees. It took two tries through the pond to get the ten males that we needed and the moment of truth was upon us; would the diaper prototype work? Unfortunately, once we placed the diapers on the turtles, we quickly found out they did not work for Hicatee!

Once in the water, they would swim out of them or not be able to swim freely. We spent the entire day developing a new design that would stay on the turtle without impeding movement. By the late afternoon, we developed a design that worked using my t-shirt and duct-tape (At least I would have less clothes to wash back home!). That evening we went for a celebratory swim in the Blue Pool, a portion of the river that is ideal for swimming and basking. The fish in the water gave us a Belizean pedicure and even removed a few ticks that were sneaky and attached themselves without us noticing.

Saturday, February 25th ‚Äì We had an early start again as we needed to develop diapers for the hatchling turtles. Fortunately, the same design we used for the adults worked for them, just significantly smaller. We spent the entire day taking turtle measurements, cutting fabric, fitting turtles and testing diapers in the water. By the end of the day we had 10 adult turtle diapers and 10 hatchling turtle diapers. The locals that work with us couldn’t believe we were making diapers for turtles! That evening, we climbed an old fire tower that had been placed as an observation platform for BFREE. At 34 meters high, we spotted a Great Potoo (Nictibius grandis), a rare sight!

Sunday, February 26th ‚Äì We marked and measured existing infrastructure so that we can plan to install a Hicatee nursery for the 100+ eggs that will hatch this coming summer. That night, we set up a trail camera because we had been seeing Baird’s Tapir (Tapirus bairdii) tracks circling our cabin. We also packed because the next day we would once again leave the jungles of Belize for home.

Monday, February 27th ‚ÄìYes! We caught several images of the tapirs walking around our cabin, along with a Gibnut (Agouti paca) or two. After eating breakfast, we canoed across the river and drove the 6 miles to the highway where we met our taxi driver. He was a lively man, born in Jamaica, but had lived all over the world before settling in Belize. The headliner of his mini-van-converted-to-taxi-cab was held in place by numerous colored thumbtacks, and old banana boxes lined the floor instead of carpet. He dropped us off at the airport in Independence where we hopped on the next flight to the international airport where we would catch our ride home. However, no trip to Belize is complete without a Pi√±a Colada from Jet’s Bar at the airport!

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Nichole’s work demonstrates the type of diverse research methodology that can be performed to better understand the imperiled chelonians that the TSA strives to preserve every day. Through better research and improved husbandry, the TSA can maximize the efforts for the chelonians in our assurance colonies. Additionally, newcomers like Nichole demonstrates the importance of the continued recruitment of innovative talent into the TSA so that we can more effectively carry out our commitment of Zero Turtle Extinctions. As of this writing, Nichole is gearing up for her upcoming trip to Belize, and we can’t wait to hear about their next foray into the jungle!