This species has multiple alternative common names, including the Fly River turtle, warradja, pitted shell turtle and Yirrin.
Little is known about how pig-nosed turtles communicate or perceive their surroundings. The nose is used for snorkeling in murky water, and contains sensory receptors that are used to detect and locate their prey. Like other turtles, they have eyes for visual perception of their environment, although the turbid waters in which they are often found likely relegates vision to a secondary sensory role. They also have well-developed inner ears, which are capable of detecting a wide range of sound frequencies.
Communication Channels: tactile
Other Communication Modes: scent marks
Perception Channels: visual ; tactile ; acoustic ; chemical
Pig-nosed turtles are considered vulnerable by the IUCN Red List and are a CITES Appendix II species. This species has experienced a dramatic population due to overharvest as a food source. In Kakadu National Park, pig-nosed turtles can gain protection from feral buffalos, which crush pig-nosed turtle eggs buried in river banks, if they live in the Alligator region of the park. Austraila has attempted and failed to preserve their habitat through their Australian EPBC Act.
US Federal List: no special status
CITES: appendix ii
State of Michigan List: no special status
IUCN Red List of Threatened Species: vulnerable
Maternal choice of nest site can have a great impact on embryonic development, determining offspring sex and survival rate. Pig-nosed turtles exhibit temperature-dependent sex determination. Both males and females are produced when eggs are incubated at 32°C. Males are produced when the temperature is decreased by half a degree and females are produced when the temperature increases by half a degree. Like other turtles, pig-nosed turtles exhibit indeterminate growth and do not go through any type of metamorphosis.
Development - Life Cycle: temperature sex determination; indeterminate growth
There are no known adverse effects of pig-nosed turtles on humans.
In New Guinea, pig-nosed turtles are hunted for meat. Their eggs are highly prized and are sold in markets. If adults are caught, they are usually traded off for something more profitable at the market. Local people eat pig-nosed turtles often, both for their taste and high protein content.
Positive Impacts: food
These turtles act as predators of several species of aquatic invertebrates and riparian plants. Their eggs serve as as prey to several lizard species. Pig-nosed turtles also provide an ecosystem service by aerating soil while digging holes during the nesting season. Known parasites of pig-nosed turtles include three species of flatworms, two of which (Doodytrema carettochelydis and Paradeuterobaris novaguieae) were first described from this species.
Ecosystem Impact: soil aeration
Commensal/Parasitic Species:
The diet of pig-nosed turtles varies by life stage. At hatching, nutrition comes from the left-over yolk of the egg. As they grow, they turn to small forms of aquatic life such as insect larvae, small shrimp, and snails. These three types of food are easily accessible and are found where they hatch, preventing them from having to leave their hole. Adult pig-nosed turtles are omnivorous, but prefer to eat more plant matter such as flowers, fruits, and leaves found at the riverbank. They also eat mollusks and insects.
Animal Foods: insects; mollusks; aquatic crustaceans
Plant Foods: leaves; fruit; flowers
Primary Diet: carnivore (Insectivore , Molluscivore ); herbivore (Folivore , Frugivore ); omnivore
Pig-nosed turtles have a very restricted range, being found in the northernmost river systems of the Northern Territory of Australia and in southern lowlands of New Guinea. These turtles inhabit several rivers within the Northern Territory, including the Victoria and Daly River systems. The southernmost extent of their range is 14˚04’40”S latitude and the easternmost extent is 131˚15’00"E longitude, during the dry season.
Biogeographic Regions: australian (Native )
Pig-nosed turtles inhabit freshwater and estuarine bodies of water. They are normally found on beaches or in ribbonweed beds of ponds, rivers, creeks, lakes, brackish water, and thermal springs. Females prefer sandy flat rock microhabitats whereas males prefer isolated log microhabitats. Both sexes show equal preference for ribbonweed bed microhabitats.
Habitat Regions: tropical ; freshwater
Aquatic Biomes: lakes and ponds; rivers and streams; temporary pools; coastal ; brackish water
Wetlands: swamp
Other Habitat Features: estuarine
Pig-nosed turtles have been reported to live 38.4 years in captivity. No information is available regarding the lifespan of this species in the wild.
Range lifespan
Status: captivity: 38.4 (high) years.
Average lifespan
Sex: female
Status: captivity: 17.3 years.
Pig-nosed turtles have large bodies and a nose similar to that of a pig, giving them their common name. These turtles lack bony scutes overlaying their shell, which has a leathery texture akin to that found in softshell turtles. The plastron is cream-colored, while the carapace can vary between different shades of brown to dark gray. They have flat, broad limbs that have two claws each, with their enlarged pectoral flippers having a similar appearance to those of sea turtles. These flippers lead to a rather clumsy gait on land, thus leading pig-nosed turtles to spend most of their time in the water. Pig-nosed turtles have strong jaws and short tails. An adult's size depends on its habitat, with individuals near the coast being much larger than those near rivers. Female pig-nosed turtles tend to be larger than males in size but males tend to have a longer and thicker tail. Adults can be as large as half a meter long, with an average weight of 22.5 kg and an average shell length of 46 cm.
Average mass: 22.5 kg.
Average length: 46 cm.
Sexual Dimorphism: female larger
Other Physical Features: ectothermic ; bilateral symmetry
Adult pig-nosed turtles are relatively well protected from predators by their tough shells, with the only real threat of predation coming from humans. Their eggs, however, are highly vulnerable to predation by other organisms. A study at the beaches near the Daly River found that eggs were being consumed by two lizard species (Varanus panoptes and Varanus mertensi). This study suggested that predation was lowest when pig-nosed turtles laid eggs in clusters rather than in single nests.
Known Predators:
Little is known about the mating habits of pig-nosed turtles, but given the evidence for multiple paternity and observed polygyny in several turtle species, it seems likely that this species is similarly promiscuous. Studies have indicated that mating occurs in the water. Males never come out of the water and females only come out when they are about to lay eggs. They don’t return to land until the next nesting season.
Mating System: polygynandrous (promiscuous)
Pig-nosed turtles are oviparous and breed during the dry season. In the Daly River, turtles nest and lay two clutches of eggs during the dry season (July-October), every other year.
Breeding interval: Pig-nosed turtles lay two clutches of eggs, every two years
Breeding season: Pig-nosed turtles nest during the dry season, which falls between July and October.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; oviparous
Females invest energy in the pre-hatching stage, whereas males provide no investment. Females look for the best place with the lowest predator density to lay their eggs, which they do by communicating with other females of the group with whom they travel. The best laying sites have soil with an ideal moisture content to easily make a nest chamber. They tend to avoid nesting at low elevations because of the chances of egg loss due to flooding. Females also avoid beaches that are dominated by submerged vegetation.
Parental Investment: female parental care ; pre-hatching/birth (Protecting: Female)
The pig-nosed turtle (Carettochelys insculpta), also known as the pitted-shelled turtle or Fly River turtle, is a species of turtle native to northern Australia and southern New Guinea. It is the only living member of the family Carettochelyidae, which are related to softshell turtles.
C. insculpta is the only living member of the genus Carettochelys, the subfamily Carettochelyinae, and the family Carettochelyidae, with Carettochelyidae being one of two families in the Trionychia, alongside Trionychidae (softshell turtles). Carettochelyidae has an extensive fossil record extending into the Paleogene and was formerly widespread, with fossils having been found in Asia, North America, Europe, Africa and Australia.[5] Some literature claims two subspecies, but a recent paper rejects this.[6]
The pig-nosed turtle is unlike any other species of freshwater turtle in its combination of traits. The feet are flippers, resembling those of marine turtles. The nose looks like that of a pig, having the nostrils at the end of a fleshy snout, hence the common name. The carapace is typically grey or olive, with a leathery texture, while the plastron is cream-coloured. Males can be distinguished from females by their longer and narrower tails. Pig-nosed turtles can grow to about 70 to 75 cm (28 to 30 in) carapace length, with a weight of over 20 kg (44 lb).
Unlike the soft-shelled turtles of the family Trionychidae, pig-nosed turtles retain a domed bony carapace beneath their leathery skin, rather than a flat plate. They also retain a solid plastron, connected to the carapace by a strong bony bridge, rather than the soft margin of the trionychids.[7]
Pig-nosed turtles are not completely aquatic. Little is known about their general behaviour, as there have been few studies in the wild. Their known extreme aggression[8] in captivity suggests the species is markedly more territorial than most other turtles and tortoises. They seem to display a degree of social structure during the cooler dry season around the hydrothermal vents that line some river systems they inhabit.
C. insculpta is omnivorous, eating a wide variety of plant and animal matter, including the flowers, fruit and leaves of figs, as well as crustaceans, molluscs and insects.[9]
Females of C. insculpta reach maturity at 18 or more years, and males around 16 years. They lay their eggs late in the dry season on sandy river banks. When the offspring are fully developed, they will stay inside the eggs in hibernation until conditions are suitable for emergence. Hatching may be triggered when the eggs have been flooded with water or by a sudden drop in air pressure signaling an approaching storm.
Using environmental triggers, along with vibrations created by other hatching turtles in the same clutch, gives a better chance for survival. Using a universal trigger rather than simply waiting for incubation to finish means they all hatch at the same time. This provides safety in numbers; also, the more turtles that hatch, the more help they have to dig through the sand to the surface.
C. insculpta is native to freshwater streams, lagoons and rivers of the Northern Territory of Australia, as well as to the island of New Guinea, where it is believed to occur in all the larger, and some smaller, southward-flowing rivers.[10]
C. insculpta experienced a population decline of more than 50% in the thirty years between 1981 and 2011.[11] Although the turtles are protected in Indonesia under Law No. 5/1990 on Natural Resources and Ecosystems Conservation, smuggling occurs. Some 11,000 turtles captured from smugglers were released into their habitats in the Wania River, Papua Province, Indonesia, on 30 December 2010. In March 2009, more than 10,000 turtles retrieved from smugglers were also released into the Otakwa River in Lorentz National Park.[12] 687 pig-nosed turtles were seized at an Indonesian airport in March 2013. They were reportedly destined for Hong Kong.
In Papua New Guinea, herpetologist Yolarnie Amepou runs the Piku Biodiversity Network Inc. which empowers local communities to monitor turtle populations and set their own targets for harvest, in the hope of building sustainable practices to preserve the population.[13][14][15][16]
Illegal harvest and trafficking of pig-nosed turtles continues on a large scale. An analysis of 26 reported seizures over the period 2013 to 2020, of which 20 took place in Indonesia and the remaining five in other parts of Asia with the turtles being trafficked from Indonesia, involved a total of 52,374 pig-nosed turtles.[17]
Pig-nosed turtles have become available through the exotic pet trade, with a few instances of captive breeding. While juveniles are small and grow slowly, their high cost and large potential size makes them suitable only for experienced aquatic turtle keepers. They tend to be shy and prone to stress. They get sick easily, which can cause problems with their feeding, but they are known to eat commercially available processed turtle pellets or trout chow, as well as various fruits and vegetables. Breeding is rarely an option to the hobbyist, as adults are highly aggressive and will attack each other in all but the largest enclosures.
Wild populations of this turtle are declining rapidly because of illegal capture for the pet trade. It is estimated that between 2003 and 2013, more than 80,000 individuals were confiscated in 30 seizures in Papua New Guinea and Indonesia.[18]
The pig-nosed turtle (Carettochelys insculpta), also known as the pitted-shelled turtle or Fly River turtle, is a species of turtle native to northern Australia and southern New Guinea. It is the only living member of the family Carettochelyidae, which are related to softshell turtles.
