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Common Names: Jansens Ratsnake, Celebes Black Tailed Ratsnake
Scientific Name: Gonyosoma jansenii
First Described: BLEEKER, 1858

Adult Size: 170-180cm
Temperament: Shy and defensive
Temperature & Humidity Range:  Provide a thermal gradient of between 29°C (84°F) to 25°C (77°F) Required humidity is between 80-90%,  provide a humid hide and mist the enclosure with tepid water twice a day.
Brumation: No brumation needed
Reproduction: Gonyosoma jansenii appears to only produce one clutch per year with an average of  5 eggs in each  which hatch from 123-125 days at an incubation temperature of between 27-29°C
Known Mutations: Melanistic
Melanistic, all black Gonyosoma jansenii  occur on the island of Salayar, it is not not known whether it is a genetic (eg: simple recessive) trait, as the unique characteristics of this island form have bred to like so far.
Captive Bred Localities: Salayer,
Natural History: A montane, semi arboreal species, it is found in rainforests at an altitude of between 100 and 1000m. In the wild the diet of Gonyosoma jansenii consists of,  Mice, Rats, Birds, Squirrels & Bats.
Native To: Gonyosoma jansenii appears to be isolated to its own specific island in Indonesia. The Black Tailed  G. jansenii is found only on the Indonesian island of Sulawesi / Celebes (Schulz 1996), and the Black (Melanistic) G.jansenii appears to be isolated to the small island of Salayar just off the southern coast of Sulawesi.

Map showing the distribution of Gonyosoma jansenii ( Jansen's Ratsnake ) in the wild.
  • Clicking the snake icons will bring up an information bubble with more information about the species occurance in that area.
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SCHULZ, Klaus Dieter (ed.), 2013. Old World Ratsnakes, A collection of papers
SCHULZ, Klaus Dieter, 1996. A monograph of the Colubrid Snakes of the genus Elaphe Fitzinger.

Scale Counts:
Ventrals: 245-257
Subcaudals: 130-140
Dorsals: 23-25
  • Jansens Ratsnake
  • Author: Batwrangler (CC BY-NC-ND 2.0)
  • Jansens Ratsnake
  • Author: Batwrangler (CC BY-NC-ND 2.0)
  • Jansens Ratsnake
  • Author: Batwrangler (CC BY-NC-ND 2.0)
  • Salayar Locality
  • Author: icizej
  • Sulawesi Locality
  • Author: icizej
  • Jansen's Ratsnake
  • Author: Rob Kool
  • Salayar 'Black'
  • Author: Batwrangler (CC BY-NC-ND 2.0)
  • Jansens Ratsnake
  • Author: Jan Petersen

Conservation Status:
IUCN Red List: Not Listed

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This site has information on the following genera of Ratsnakes ... Spilotes, Spalerosophis, Ptyas, Zamenis, Elaphe, Rhinechis, Senticolis, Pseudelaphe, Pantherophis, Bogertophis, Orthriophis, Gonyosoma, Oreocryptophis, Oocatochus, Euprepiophis, Coelognathus, Archelaphe