Rare Turtle Hatchlings Grow, Learn—and Teach
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Eight rare sandstone long-neck turtles, or Chelodina burrungandjii, native to a remote region of Australia, recently hatched at the National Aquarium. We talked with Curator Ken Howell and Herpetologist Matt Benedict about their hatching and the work that goes into caring for these noteworthy turtles.
"We believe these hatchlings to be the first at any aquarium or zoo. We're really fortunate to have these turtles at the Aquarium, and their successful reproduction will allow us to contribute to the scientific knowledge of this species." Curator Ken Howell
To encourage the pair of long-neck turtles at the Aquarium to reproduce, a team of Aquarium herpetologists and aquarists sought to mimic Australia's climate and weather patterns. They simulated the rainy spring breeding season by building a rain chamber with a covered nest box in the middle, and fluctuated the temperatures of the rain, air and water to follow natural cycles.
"Although this was an experimental process and there was so much we were going to learn from it no matter what happened, I feel like we learned as much as we possibly could have from a single clutch of eggs." Herpetologist Matt Benedict
The female turtle laid a clutch of 12 eggs in July 2020. The eggs were divided into two smaller, six-egg clutches. Because there isn't scientific literature that outlines incubation temperatures and durations for this species, the team made hypotheses based on climate data of Australia's Arnhem Land region, watched the process closely and recorded their observations. They held one clutch of eggs at 85-86 degrees while the other was held at 81-82 degrees. A few days after the eggs were laid, all 12 developed a visible band around them, which was a positive and exciting sign.
By holding a bright, focused flashlight against an egg in a dark room, Aquarium staff used a process called candling to monitor the eggs and see if they were developing properly. Turtle eggs are often translucent enough that candling can reveal blood vessels and the developing embryo.
The first egg began hatching in late October 2020 with the others following in November and December. The eggs incubated at the lower temperature hatched later than those held at the higher temperature and fared slightly better. One egg that initially showed no signs of development successfully hatched much later than the rest, in February 2021, which suggests that a phenomenon of suspended development, known as diapause, may play a role in the incubation strategy of this species.
While the sex of each turtle won't be clear for several years, Matt says each hatchling has a distinct personality. "They all have paint dots separating them right now, but if their paint dots came off, I could tell you which one is which based on their behaviors. Some of them are very boisterous and extroverted; when you walk by, they'll stop what they're doing and come greet you. Others are quiet and hang back, and others hide and don't want to be seen."
Because no literature exists about what this species eats at this early stage of life, Matt tried different options and recorded his observations in a table. The turtles had a wide range of preferences—some ate live prey, some would only eat fish, some fed on invertebrates while others refused. "When it's feeding time, I turn off all the filtration for less noise and so it doesn't mix the food around," Matt explains. "They know when that filter goes off that it's feeding time. They have learned my schedule and figured out the routine."
Scientists theorize that snake-neck turtles' long necks evolved as a feeding mechanism. They primarily eat fish, supplemented by invertebrates. Because fish can sense what's around them in the water, turtles with long necks are able to snap up fish before they can react. Sandstone long-neck turtles are active predators that use what's known as a strike-and-gape hunting method.
Watch the sandstone long-neck turtle hatchlings in action and listen as Herpetologist Matt Benedict describes their care.
Matt has observed the turtles' ability to learn and problem-solve. "One day I put a pyramid of PVC tubes in their habitat for enrichment, to see what they would do with it," he said. "Some climbed on top of it. One went in a tube and realized he couldn't get out. He was trying to figure it out, and eventually he backed up. Then, after figuring out that first tube, he explored each pipe, one at a time, and used the method of backing up to get out. He learned how to navigate it pretty quickly."
"It's great to feel like I’m helping this species succeed. I'm making a difference here. The more I get to learn about this species and tell people about how cool they are, the more everyone else can get excited about them and care about what happens to them and their native habitat." Herpetologist Matt Benedict
Stay tuned for more news about these turtles as they grow!