Family Emydidae – American Freshwater Turtles
This week we’ll do a dive on the remaining turtles found in our own neighborhood ponds and backyards. The survey found ~35 species held in US zoos and aquariums, with every genus represented in captivity here. Unfortunately, many of our native species are endangered; this has led to the creation of some captive breeding programs in American zoos. Some of our native turtles might be obscure to some of you, but today we’ll talk about a very familiar genus.
Terrapene – American Box Turtles
Almost like mini-tortoises, these largely terrestrial turtles with dome-shaped shells are common sights in the wild and highly popular in captivity. They can be found everywhere: major zoos and aquariums, small countryside zoos, nature centers, and privately as pets. Very hardy turtles, they can retract into their shell and protect themselves from virtually any predator by adulthood and individuals have lived to be over 100 years old. They are omnivorous, eating largely plant matter and invertebrates. There is some debate as to how many species there are, but I've identified all relevant taxa.
Common Box Turtle (Terrapene carolina) – Abundant
One of the most commonly seen captive turtles in the US, these turtles range fairly far north in the country and hibernate in the winter. While this remains one of the most commonly seen turtles in the eastern US, it is unfortunately become vulnerable due to habitat loss, harvesting for the pet trade and getting run over by cars (the one predator their shell can’t protect them from…). They are extremely common in zoos and aquariums in the eastern half of the country; conversely there are few holders in the Western states, outside its native range.
The survey found four subspecies held in the States; the most common by far is the Eastern Box Turtle (
T. c. carolina), representing two-thirds of the total. The Three-toed Box Turtle (
C. t. triunguis) – found in the south-central US and considered a distinct species by some sources – is on display at a dozen facilities at least, likely more. The Florida (
C. t. bauri) and Gulf Coast (
C. t. major) are rarer, but still found in at least a handful of places each.
Eastern Box Turtle (
Terrapene carolina carolina)
Taken in the wild (Illinois) by
@CMP
Three-toed Box Turtle (
Terrapene carolina triunguis)
Taken at the Trevor Zoo (New York) by
@ThylacineAlive
Ornate Box Turtle (Terrapene ornatus) – Common
Another vulnerable species, also called the Western Box Turtle. There are two subspecies, both found in the survey – the nominate (
C. o. ornatus), found in grasslands and woodlands from the Midwest to Texas; and the Desert Box Turtle (
C. o. luteola), common in the southwestern deserts of New Mexico and Arizona. I wasn’t able to confirm the subspecies for most holders, but there seems to be several holdings of both.
Desert Box Turtle (
Terrapene ornata luteola)
Taken at the Omaha's Henry Doorly Zoo by
@Jena
Coahuilan Box Turtle (Terrapene coahuila) – Prevalent
Endemic to a small area of desert marsh oases in northern Mexico, this endangered box turtle is unlike our two native species in that it is predominantly aquatic – they spend enough time in the water as to have algae growing on their shells. This is a rarer species in captivity, but there is a captive breeding program for them and a handful of both larger and smaller zoos display this unusual species.
Taken at the Santa Barbara Zoo (California) by
@Coelacanth18
Other species in the survey:
Yucatan Box Turtle (T. yucatana) – Rare