If you ask our staff about the perks of working so closely with such a broad variety of animals, they'll likely share a long list of favorite things. From observing and understanding the fascinating adaptations that different species rely upon to thrive and survive, to the individual relationships our care professionals develop with Aquarium animals, there is no shortage of benefits to the demanding work put forth by our animal teams, but there is no denying that one of the most rewarding parts of the job is the front row seats to the arrival of newborn baby animals.
This spring, National Aquarium herpetologists have had the opportunity to oversee births of healthy offspring from three different and distinct Aquarium species—endangered Mary River turtles, Northern red-faced turtles and Hosmer's skinks. These newborns allow our animal husbandry experts to learn a little more about these species and, in some cases, support the continued survival of critically endangered animals.
Let's meet some of our new arrivals and learn about what makes them so much more than just adorable—but definitely that, too!
Mary River Turtles
Found only in southeastern Queensland, Australia, in the Mary River and its tributaries, Mary River turtles are noted for their unusually large tails, especially in the males of the species, and they are the largest side-necked turtle in Australia. Side-necked turtles are so named because, when threatened, they protect their heads by bending their necks horizontally and tucking into the right or left overhang space of the front edge of the shell as opposed to retracting their heads into their shells as most turtle species do. Unfortunately, Mary River turtles are endangered within their natural range in Australia and are listed on the International Union for Conservation of Nature’s Red List of Threatened Species. The National Aquarium's Australia: Wild Extremes exhibit is one of the few places outside of Australia to see these fascinating turtles—and this makes the birth of some tiny new Mary River turtles here this spring that much more interesting and important!
In the 1960s, Mary River turtles were commonly sold in pet shops within Australia even though no one knew much about their origins or anything about their biology. In fact, this species wasn't formally described in scientific literature until 1994 after noted Australian turtle authority John Cann finally located the wild population on the Mary River after searching for more than 25 years. Cann and American herpetologist John Legler described this new species and gave it the scientific name Elusor macrurus, with the genus name alluding to the search for the wild population as "elusive."
Unfortunately, their numbers are dwindling in their natural environment due to threats that include land use practices and river modifications like sand dredging. Their eggs are also threatened by non-native predators such as wild pigs and red foxes. Mary River turtles dodged a major threat in 2009 when the Traveston Dam project proposed for the Mary River was ended to protect them, along with Australian lungfish and Mary River cod.
Mary River turtles can be seen here at the Aquarium under an ambassador agreement with Australia's Department of Agriculture, Water and the Environment. Aquarium herpetologists care for a trio of adult turtles—one male and two females—as well as some of their past offspring in Australia: Wild Extremes.
This spring's hatchlings represent the third successful hatching of this rare species at the National Aquarium. These babies hatched from ten eggs discovered on March 6, that were laid in a sandy nesting area provided in the exhibit.
Under the watchful eye of Aquarium Herpetologist Drew Roderuck, the eggs were carefully excavated and set up off-exhibit in an incubator. Drew then monitored the humidity within the incubator until five of the eggs began pipping, or hatching, on April 7. Mary River turtle hatchlings, like other turtle species, have an egg tooth on their beaks, which allows them to slit open their parchment-like eggs and begin to emerge. Three of the turtles fully hatched on that day with the remaining two exiting their eggs the following day. A total of five eggs hatched successfully, while the remaining five eggs appear to be infertile.
The hatchlings are currently set up in an aquatic enclosure and all have begun feeding on small invertebrates and chopped meat and fish. The next time you visit, make sure to check out their parents and maybe some siblings in Australia: Wild Extremes.
Northern Red-Faced Turtles
As compared with Mary River turtles, the Northern red-faced turtles in our Australia: Wild Extremes exhibit are found in several remote northern Australian rivers and are not restricted to one single river. According to the Atlas of Living Australia, their populations seem stable within their geographic range. Northern red-faced turtles, which derive their name from distinctive, mask-like red markings, are one of several Australian freshwater turtle species that can be found in the northern Australian river gorge habitat that has been re-created in detail here at the National Aquarium.
When red-faced turtle eggs are laid at the Aquarium, they are collected and incubated behind the scenes of our Australia: Wild Extremes habitats, where staff carefully watch and wait through the species' two-month incubation period. The turtles weighed just a few adorable grams when they are born, and each receives a dot of non-toxic, colored paint on their shell. This allows herpetologists to differentiate the tiny turtles, monitor them and track their health and growth. The hatchlings live together off exhibit and receive daily attention from our team.
Our herpetologists place special emphasis on the turtles' interest in eating. While in their eggs before hatching, the turtles derived nutrition from a nutrient-rich yolk sac. Some of the yolk sac may still be present after they hatch, so it can take a couple days—sometimes even weeks—until a hatchling is hungry and eager to eat on their own. Their keepers are careful to track each individual's appetite and preferences, and each turtle is weighed and measured every few days.
The turtle hatchlings will continue to live off-exhibit until they are at least four-inches long—that's about half of their adult size of up to ten inches—a process that can take several years. This timeline both ensures the turtles' general health and allows them to reach a size at which they are no longer vulnerable to other species within their habitat space. Some might remain here at the Aquarium while others might move on to other zoos or aquariums.
Hosmer's Spiny-Tailed Skink
Ladies and gentlemen, meet the National Aquarium's newest Hosmer's spiny-tailed skink, Marvin. These rock-dwelling lizards are found in the arid habitats of Queensland and the northeastern edge of the Northern Territory. Hosmer's skinks are moderate-sized members of the skink family and grow to a maximum size of nine inches. They are omnivorous, existing on a diet of insects, leaves and berries, and they live in small colonies. The scales on their body have three to four sharp points known as keels, and the scales on their tails each have a long spine. When threatened, they wedge themselves into rocky crevices and puff up their bodies so that their spiky spines can grip the surrounding rocks.
A fascinating adaptation displayed by Hosmer's skinks is viviparous birth. Instead of laying eggs like a typical lizard, the young develop in their mother's body, and she gives birth to fully developed baby skinks. Baby Hosmer's skinks look just like tiny replicas of their parents at birth, with light yellow-brown to brown coloring and creamy to dark brown blotches that are more prominent around their heads.
While Hosmer's skinks can give birth to up to four offspring at a time, Marvin was a single birth, arriving on March 4, and is currently being cared for behind the scenes. Some species of skinks, including Hosmer's skinks, are known to form long-lasting familial bonds and parents will offer juveniles ongoing care, from support in finding food to protection from predators.