Pig-Nosed Turtle

Scope of Studbook

This North American regional studbook is current through 31 Decemnber 2000. It contains 76 (20.25.31) specimens of which 34 (10.8.16) are living. All known current and historical holding institutions have been included. The first specimen, studbook number 101, transferred into the NY Bronx collection on 26 July 1958, is still alive.

This studbook was approved by the Wildlife Conservation & Management Committee on 9 October 1996 and was announced in the December 1996 AZA Communiqué. Private sector participation had been sought but is not reported on here.

Need for this Studbook

The initial 1998 publication of a studbook for a taxa not documented to have reproduced in captivity may have appeared optimistic and even premature. Now that captive reproduction has occurured, however, it is hoped that this studbook will help to facilitate sound husbandry and eventual captive reproduction of this unique chelonian species. As studbooks are living documents, later editions should include many captive reproduction events.

Definition and Description of the Taxon

The pig-nosed turtle is also know as plateless turtle, Fly River turtle, and pitted shell turtle. S. Thomson (pers. comm.) reports Pig-nosed turtles are known as Warradjan and Yirri in Australian native peoples’ languages. The original Latin designation of the pig-nosed turtle, Carettochelys insculpta, has remained unchanged since Dr. E. P. Ramsey’s 1886 description of a Strickland River specimen (Georges and Rose, 1993). The year following Ramsey’s description, Boulenger (1887) recognized the uniqueness of the pig-nosed turtle, and designated it the sole living member of the Family Carettochelyidae. No subspecies are recognized, but two populations, N. Australia and New Guinea, are being considered for distinction (S. Thomson, pers. comm.).

Pig-nosed turtles are large, up to 22.5 kg (49.5 pounds) in weight and 56.3 cm (22.25 inches) in carapace length, principally freshwater turtles (Georges and Rose, 1993). The carapace surface is covered with a smooth grayish velveteen skin, with some white areas on some specimens. The plastron, also covered in skin, not scutes, is cream white. Head is gray with white streaks behind each eye, and with white on the lower jaw. The limbs and feet are similar in form to those of sea turtles. The nares are on a fleshy projection and resemble a pig’s nose.

Distribution of Wild Populations

Pig-nosed turtles are native to southern drainage on the Island of New Guinea, and from rivers in the northern portion of Northern Territory Australia, (Iverson, 1992). http://bufo.geo.orst.edu/turtle/1.html

Captive and Wild Status

Papua New Guinea, Australia, and Indonesia currently have protective laws prohibiting the collection and/or export of `pig-nosed turtles. While not listed in the U.S. Endangered Species Act (ESA) or under the Convention on the International Trade in Endangered Species of Flora and Fauna (CITES), protection is afforded in all countries of origin; therefore, the Lacey Act does make their importation into or through the United States illegal (M. Osborn, pers. comm.). The pig-nosed turtle has an IUCN/SSC Action Plan Rating of 1, and is recognized in the Red Data Book as K, “Insufficiently Known.”

Pig-nosed turtles are considered locally abundant over most of their range, but rare in the sense of being geographically restricted. Populations in New Guinea are thought to be declining because of increased exploitation for meat and eggs. This exploitation has been exacerbated in recent times by the introduction of some 20th century technology, principally outboard motors. Clan warfare has essentially ceased, and the people have moved from the hinterland to more convenient locations along riverbanks. Levels of industrial activity such as mining; exploration for oil, gold, and copper; logging; and fishing have increased. Any of these activities has the potential to impact wildlife populations, including those of the pig-nosed turtle. In northern Australia, feral water buffalo pose a major threat through trampling of nesting banks and widespread destruction of the riparian vegetation upon which the turtles depend (Georges and Rose, 1993).

Ecology of Wild Populations

Carettochelys, as a species, are social turtles. Congregations are noted in relation to localized abundance of suitable food items (Georges and Rose, 1993). S. Thomson (pers. comm.) reports that Georges and Heaphy observed about thirteen animals, mostly males making “mating circles” in broad daylight in 1986. “They [pig-nosed turtles] all move around in a circle, which leaves a circle of clean sand on the river bed, which you can see for about fifty meters.” In the wild, males and females are often found basking and feeding together without any apparent conflict.

Pig-nosed turtles are omnivorous with herbivorous tendencies (Groombridge, 1982). A wide variety of aquatic plants are eaten as well as the leaves and fruits of riparian vegetation. Live aquatic invertebrates are consumed along with carrion of invertebrates, fish, and possibly mammals (Georges and Rose, 1993).

Pig-nosed turtles inhabit freshwater and estuarine habitats typified by rivers, grassy lagoons, swamps, lakes, and water holes. Preferred aquatic substrate is sand and gravel covered with silt and litter. Underwater cover, in the form of fallen trees, vegetation and bank overhangs, and litter accumulations are utilized (Georges and Rose, 1993). S. Thomson (pers. comm.) notes the Daly River in northern Australia has water temperatures of 27–28°C (80–83°F) in winter and up to 32°C (89°F) in summer. This species is restricted to limestone rivers with high conductivity and high pH that does not drop below 7.50 in the wet season and remains at about 8.20 in the dry season.

Pig-nosed mating in the wild has not been documented in any detail. Females choose clean fine sand adjacent to water to nest during the dry seasons for both northern Australia and New Guinea populations. The eggs are white, hard-shelled spheres weighing about 34 gms (1.2 oz) with a diameter of 39 mm (1.5 inches). Clutch size of eggs are reported to range from 7 to 39 eggs. Cann (1978) suggests that the larger clutches are likely to be found in areas where there is much nesting activity, the result of multiple females using one nest site.

Incubation at 30°C (86°F) takes 64 to 74 days. At this stage embryos aestivate in the egg. Hatching can be stimulated by placing developed eggs in an oxygen-reduced environment, such as submersion in water. This suggests that wild nests are stimulated to hatch during the end of the dry season with rain or actual flooding of nesting beaches (Georges and Rose, 1993).

Status of Museum Collection Specimens

Studbook specimens are specifically designated as those animals having been alive in the region designated in the scope of the studbook. The following are now part of museum collections; many of which came from zoos, and had been a part of the living collection in the North American Region.

	California Academy of Sciences	6 specimens
	Carnegie Museum	5 specimens
	Museum of Natural History, University of Kansas	1 specimen
	Museum of Zoology, Louisiana State University	1 specimen
	National Museum of Natural History (United States)	7 specimens
	University of Michigan, Museum of Zoology	undeclared number
	University of Texas at Arlington	4 specimens

These museum holdings are listed through the California Academy of Sciences’ Web Page http://www.calacademy.org/research/herpetology/Comb_Coll_Index/ (link opens new browser window).

Request for Specimens

[Suggestion to donate deceased specimens to museums --- text to come.]

Electronic Information Resources

The article “Conservation Biology of the Pig-nosed Turtle, Carettochelys insculpta,” by Arthur Georges and Mark Rose, which is heavily utilized in this studbook, can be seen in its entirety at http://aerg.canberra.edu.au/pub/aerg/herps/fncchely.htm.

Additional Web pages concerning this taxa can be found at the California Turtle and Tortoise Club’s archives, www.tortoise.org/archives/pignose.html, and
the Applied Ecology Research Group’s Web page,
http://aerg.canberra.edu.au/pub/aerg/images/turtles/capict.jpg, and
http://aerg.canberra.edu.au/pub/aerg/images/turtles/htcaret.jpg.
John Iverson’s range map may be found at http://bufo.geo.orst.edu/turtle/1.html.

Recommendations

It has been suggested by F. Yuwono (1997, pers. comm.) that institutions in the U.S. that wish to expand their holding of pig-nosed turtles make appropriate affiliations with institutions in any of the countries where pig-nosed turtles are native. It should also be stressed that accurate records of pig-nosed turtles in the U.S. be maintained. Positive identification of each animal by means of an implant or blood sample should be employed.

Pig-nosed turtles continue to be available to some individuals who seek them (F. Caporaso, pers. comm.). It has been suggested that because they do not have ESA or CITES protection, they are easy to hide among wildlife exports that are of a similar legal status. Giving these chelonians additional protection outside their native countries might be a useful means to curtail some of the illegal trade that presently exists.

Acknowledgments

I wish to express my gratitude to President and CEO of the Philadelphia Zoological Gardens, Alexander "Pete" Hoskins for supporting this project. I wish to acknowledge Senior Vice-President for Animal Affairs, Karl Kranz, and Curator of Amphibians and Reptiles, Dr. Kevin Wright for their encouragement in this time-consuming project. I also thank the Chelonian Advisory Group for supporting the formation of this studbook.

In addition, Philadelphia Zoological Gardens Animal Collections Manager Beth Bahner has been a constant and positive source of encouragement to me, without which I probably would not have finished this project. Bill Konstant, past Vice-president of Conservation at PZG also offered words of inspiration that encouraged me to complete the project. The AZA Studbook and Population Management Plan schools, instructors, and classmates have been a tremendous resource and proved indispensable.

Other individuals and organizations helped greatly, and I am grateful to each individual. Specifically, Scott Thomson of the Applied Ecology Research Group, University of Canberra in A.C.T., Australia; Fred Caporaso of Chapman University in Orange California; Frank Yuwono of Terraria Indonesia in Jakarta, Indonesia; Joe Ventura and Mike Osborn of the USFWS in Torrance, California; and Allen Salzberg of Forest Hills, New York have provided important insight in the form of extended personal communications regarding the ecology and trade of these unique chelonians. Sean McKeown, Dave Collins, and James Buskirk have generously responded with valuable comments and criticism to an earlier rough draft of the first printed edition.

I alone am responsible for any errors reported in this studbook. If you encounter any, I hope you will let me know so that future editions will be more accurate.

Respectfully,
William H. Espenshade III