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An initiative of Earthwatch Institute

  1. 121 Photo by Sandra Wallace
  2. 121_0 Hatchlings photo by Atlanta Veld
  3. 121_1 Nesting photo by Atlanta Veld
  4. 121_2 Nesting photo by Atlanta Veld
  5. 121_3 Nesting photo by Atlanta Veld
  6. 121_4 Photo by Atlanta Veld
  7. 121_5 Photo by Atlanta Veld
  8. 121_6 Turtle crossing photo by Atlanta Veld
  9. 121_7 Turtle nest photo by Atlanta Veld
  10. 121_8 Photo by Atlanta Veld
  11. 121_9 Photo by Jonathon Lee

Oblong Turtle

Chelodina colliei (SW WA) and Chelodina oblonga (N WA & NT)

Appearance

  • Colour: The carapace (upper shell) ranges in color from light brown to black. The olive to gray neck is thick, with blunt rounded tubercles,
  • The head is large and flat with a protruding snout and an unnotched upper jaw.
  • Size: Adult Shell length can be between 30 to 40 cm

Behaviour

  • Diet: Fish and tadpoles aquatic invertebrates, baby waterbirds
  • Movement: When prey is in range the Oblong turtle can strike its head forward to seize it. 
  • Breeding: Males become sexually mature at a carpace length of 14 cm.  Females with a carpace of 15 - 21 cms are usually mature.  Nest sites are usually open and free from thick vegetation, and once the maximum daily air temperature remains above 17.5°C the females come ashore to nest. Nesting in Spring is triggered by a falling trend in barometric pressure below 1015Hpa. Females can lay up to three clutches during the nesting season from September to January. Each clutch ranges from 3 -15 eggs The natural incubation period ranges from 183 to 222 days, depending on weather conditions. Hatchlings are approximately 31 mm in carapace length.  

What to Observe

  • Behaviour select one behaviour from the list (Basking, Feeding, Courting/mating, Nesting, Hatched eggs, Presence of juveniles, Migrating)
  • Turtle Observed select one environment surface from the list (on grass, on road, on pavement, on a log, in water, in shrubs)
  • Shell Size select one size from the list (Longer than a soft drink can (>13cm), Medium length (between 6 – 13cm), Shorter than the top of a soft drink can (<6cm))

ClimateWatch Science Advisor

Turtles are particularly vunerable to Climate Change.  Effects include decreases in clutch size, hatching success and loss of nesting areas. Habitat degradation and loss. Temperature also affects the gender of hatchlings.  Warmer nesting areas may produce more females.

These turtles don’t tend to aestivate over summer so drying out of aquatic habitat causes increases in mortality. Poor quality habitat can cause females to halt reproduction indefinitely until conditions become favourable, causing a reduction in recruitment and bottlenecking of populations, increasing the risk of population crashes. 

When To Look

  • September - January for nesting
  • May - September for hatchlings
  • Males and females will also move from one swamp to another as the habitat dries up or food becomes scarce.

Where To Look

  • South west of Western Australia
  • South of Jurien and along the south coast to Fitzgerald River National Park.

  • Freshwater swamps and streams are the primary habitat.

  • Look for nesting females and hatchlings around wetlands, grassed lawns, urban backyards, in the vicinity of fresh water including park lakes and dams.

Oblong Turtle distribution map - GBIF

Chelodina distribution map - GBIF

Where To Look

Maps of Habitat Suitability

Chelodina_oblonga-northern_long_necked_turtle

Current probability
of occurrence
2070 probability
of occurrence (RCP 8.5)
Species range change from
current to 2070 probability

Above, the left and middle maps show the modelled habitat suitability for the the species under current and potential future climate conditions. The colours indicate the predicted habitat suitability from low (white) to high (dark red).

The future habitat suitability is modelled for the year 2070 under a climate change scenario that represents 'business as usual' (RCP 8.5). The map on the right shows how the range of the species might change between now and 2070, with orange areas indicating where the species might disappear, green areas where the species range might expand, and blue areas where the habitat is predicted to be suitable for the species now and in the future.

The models for this species were run in the Biodiversity and Climate Change Virtual Laboratory. Please note that while models can be very informative, they are only a representation of the real world and thus should always be viewed with caution. You can read more about the science behind these models here.

Sightings

References

Cogger, H. G. 2000. Reptiles & Amphibians of Australia, Sixth Edition

Browne-Cooper, Robert; Brian Bush, Brad Maryan, David Robinson 2007. Reptiles and Frogs in the Bush: Southwestern Australia. University of Western Australia Press.

  1. Search Species

  1. What Else?

    Similar to the Flat-shelled snake-necked turtle but the upper shell or carapace is much longer than wide; ie oblong.

  1. Did You Know?

    The original specimen collected and given the name Chelodina oblonga is now thought to be from a species of long necked turtle found in northern WA and the Northern Territory, the Northern Long-necked turtle Macrochelodina rugosa. The first specimen of the oblong turtle seen in southwest WA was originally called Chelodina colliei

    No-one really knows how long they live for but it can be up to as long as humans – 80 years or more.

    This species is also known as the Snake-necked or Western long-necked turtle.