Success In An Elusive F2 at The Knoxville Zoo

Once upon a time, an interesting species of turtle became extinct. Last seen in 1908, the Arakan Forest Turtle, Heosemys depressa, disappeared and was never seen again. (This seems like a sad story, but stick with me.)

About 100 years later, in 1994, a scientist visiting a food market in Asia was astounded to find a few of these animals for sale! A relic population was discovered, and animals were taken into captivity in the hopes of forming assurance colonies and potentially increasing its numbers.

With wild-caught animals in general, and reptiles in particular, breeding isn’t a straightforward endeavor. With dogs and cats, boy + girl = offspring too numerous to count. With wild animals, the equation can be far more complicated. We are just beginning to understand and respect the complex social signals and mating rituals many animals require in order to reproduce. Cheetahs, for example, need a choice of more than one male in order to breed successfully. In the last ten years or so, our thoughts on cheetah reproduction has changed dramatically, and zoos have moved their charges to breeding centers when trying for cubs rather than keeping specific pairs of animals.

To complicate matters further, getting the first generation of wild-caught animals to breed doesn’t mean the species is automatically saved.  The offspring of these wild-caught animals are noted in the studbook as F1, the first generation born in captivity. Since it is no longer desirable, or in some cases even possible, to continue to take animals out of the wild, it is important that the F1 generation reproduce themselves. Breeding programs for many different species are in a race to produce the next generation, the captive-bred’s captive-bred, the elusive F2.

Sometimes that doesn’t happen. Take the white rhinoceros, for example. Animals taken from the wild, even as juveniles, have bred fairly successfully in zoos. The two older females at our zoo, for example, have produced an impressive ten calves apiece over the last 30 years or so. There are plenty of F1 calves in zoos around the country. But for reasons poorly understood at this point, there have been precious few F2s. The offspring of the wild ones are not having babies of their own.

Producing an F2 is a pretty big deal. It means that the diet and care given to the animal are more or less correct. It means that we’re moving in the right direction, and that we may be able to save some critically endangered species.

The Arakan Forest Turtle, an animal whose life in the wild we still don’t fully understand even 20 years later and whose diet and husbandry has been educated guesswork, has been bred in captivity several times. That’s great news, of course. But zoos and private breeders have been working with that F0 generation and producing  only F1s. Until now.

Without further ado, I’d like to introduce you to the first F2 Arakan Forest Turtle in the world, hatched at Knoxville Zoo on May 28th 2014.

f2 Arakan Forest Turtle - 1
I looked in the incubator one afternoon, and this guy was looking back at me — F2 Arakan Forest Turtle


f2 Arakan Forest Turtle - 2


f2 Arakan Forest Turtle - 3


f2 Arakan Forest Turtle - 4
Belly button!


f2 Arakan Forest Turtle - 5

This development is especially exciting because, unlike species who are endangered due to habitat destruction, there is still wild habitat for these animals to return to. If they continue to be bred in captivity in reasonable numbers, they may one day be able to go home.

So here’s  a shout-out right here to Brad Moxley, dedicated keeper at Knoxville (my) zoo. Congrats, Brad! Your hard work  is paying off! It’s an honor to work with you, sir.

Original version published at Becoming Cliche.  Reposted, in full, with permission of the author.




  1. That Arakan Forest Turtle sure is a cutey!

    Congrats to the Knoxville zoo! To think the save started at the market (not in the forest), 100yrs after extinct and THEN all the right steps that were needed along the way… What are the odds? The whole story makes me grin…


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