Dendrelaphis pictus, Gmelin, 1789 Painted Bronzeback

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English name: Painted Bronzeback

Scientific name: Dendrelaphis pictus

Chinese name: 过树蛇

This non-venomous colubridea is one of the most commonly encountered snakes in Southeast Asia. It is present in ranging habitats such as cultivated areas, garden and parks, shrubs and forests (Lim and Lee, 1989; Stuebing and Inger, 1999; Chan-Ard et al., 2001).

This small and slender snake is easily identified through its bronze dorsal colouration and a blunt snout. It has a diagnostic black eye-stripe beginning on the snout, passing through the eye and continuing down each flank. There is a cream lateral stripe beneath the black stripe along the length of the body. Its dorsal region has a cream or yellowish colouration (Ecology Asia). It can grow up to 120 cm with tail being one-third (Edward, 1874)
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Black eye-stripe from snout across the eye running down its body (Photo by:Colleen)



Diagnosis


Characterization of Dendrelapis has been done by Rooijen and Vogel (2008) as well as Nicholson Edward (1874)

  1. 15 dorsal scale rows at midbody
  2. one loreal scale
  3. 6-7 temporal scales
  4. supralabials 4,5 and 6 touch the eye (4th with posterior corner)
  5. a short first sublabial that touches infralabials 6 and 7
  6. vertebral scales strongly enlarged, larger than the scales of the first dorsal row
  7. 183-189 ventrals
  8. 126-133 subcaudals
  9. a divided anal shield
  10. a relatively compact build, snout-vent length/ head-length 23.5-28.5
  11. a black postocular stipe that starts on the loreal, covers the whole temporal region and textends onto the neck where it is broken up oblique black bars
  12. the presence of black narrow stripe in the posterior half of body, covering the lower half of the third dorsal row
  13. the absence of a light ventrolateral stripe

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Head scale of snake (Picture by Shanshan)

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Scalation of a snake (Photo adapted from Wikipedia)


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Drawing of Dendrelaphis pictus Adapted from India Snakes, Nicholson Edward (1874)

Biology


This diurnal species is predominantly arboreal. It can also be found on the edge of small clearings or in other habitat transitions for basking.


Prey and Being Preyed


It actively hunt on lizards and amphibians primarily (Rooijen and Vogel, 2008).
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Dendrelaphis pictus preying on Copper-cheeked frog Rana chalconata (Photo by:Nick Baker @Ecology Asia)

Some cases of high "self-estimation":

A sub-adult Dendrelaphis pictushas been spotted in attempting to swallow a large tadpole prey in Singapore Zoo. The snake was resting on a waterlily (Victoria amazonica) with a tadpole which was identified as common greenback, Hylarana erythraea (Leong et al., 2009). The sub-adult was estimated to be 50 cm with a head width of 5-6 mm. The tadpole has noticeable skin tear and compression which matches the outline of snake's upper jaw.
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A sub-adult painted bronzeback resting on waterlily with an abandoned tadpole (arrow) Photo by Charlene Yeong permission pending


Picture on the left shows Dendrelaphis pictushas been spotted on habitat transition, grass patch of Nanyang Technology University, Singapore. The frog is likely to be a Field frog, Fejervarya limnocharis.

Due to its small body size, it also provide food for larger snakes and birds for prey.
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Painted bronzeback with its prey Field frog spotted in NTU (Photo by Sheng Xiaomeng)

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Being preyed by Crested Serpent-Eagle (Photo taken in Borneo by: Nigel Voaden)

Behaviour


This active snake has restless habit and quick movement.

It is usually shy and will flee quickly when disrupted. In time of threat, when it is cornered with no where to flee, it will inflate its body and flatten the neck laterally to reveal turquoish colour, wide gape and bright red tongue.
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Bluff striking (Photo by:Francis Cosquieri, permission pending)



Dendrelaphis pictus is an inoffensive creature (Video taken in Thailand by: Vern L.)
Dendrelaphis pictus found under mattress (Video taken in India by Faazea)


Reproduction


Oviparous. Has been reported to lay 3-8 eggs in hollow tree stem.Period of gestation is believed to be 4 to 6 months and eggs hatch 4 to 6 weeks after laying. Development begins before they are voided (Daniel, 2002). Neonates hatch to be minature of adult snake are usually 8-12 cm long.

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Neonates of Dendrelaphis pictus (Photo by: Francis Cosquieri, permission pending)


Distribution


Dendrelaphis pictus ranges from India, Myanmar, Southern China, Thailand, Peninsular of Malaysia, larger islands of Indonesia, Philippine Island and Singapore. It is widely observed in all habitats in Singapore and thus considered the most commonly encountered snake here.

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Sexual Diamorphism


Sexual dimorphism in morphology or body size is common among reptiles (Camilleri and Shine, 1990) . More than 60% of taxa of snakes are sexually dimorphic in adult body size with female larger than males (Shine, 1978).

In Dendrelaphis, females grow larger than males. Studies have done on head measurements and shown that females have relatively larger heads (Camilleri and Shine, 1990). This trait has been identified in many other species (Greene et al., 1997). Dietary divergence might be the important selective force for the evolution of head-size and shape dimorphism. Males have been reported to have larger eyes than females (Greene et al., 1997).


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Head measurements done in Dendrelaphis (Camilleri and Shine, 1990)


Close Relatives


Dendrelaphis has more than 40 de scripted species and some of them are closely alike.

D. pictus
Painted Bronzeback

  • Black eye-stripe

  • Posterior maxillary teeth bring longer than the rest
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Painted Bronzeback (Photo by Colleen)

D. tristis
Common Indian Bronzeback

  • Posterior maxillary teeth being shorter than the rest

  • Closest in morphology to painted bronzeback
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Common Indian Bronzeback (Photo by Dinesh Valke permission pending)

D. cyanochloris
Blue Bronzeback

  • Closely related in morphology to Elegant Bronzeback

  • Black eye-stripe which starts immediately in front of the eye and extends onto the neck only

  • Eyes slightly smaller
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Blue Bronzeback Photo by Norhayati Ahmad permission pending

D. haasi
Haas' Bronzeback

  • Body is much more slender

  • Head colour is orange

  • Lacks black stripe behind the eye and down the neck

  • Occurs near streams
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Photo by Nick Baker

D. kopsteini
Kopstein's Bronzeback

  • Brick-red back of the neck, best seen when expanded
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Photo by Nick Baker

D. formosus
Elegant Bronzeback

  • Back is brown and highly keeled with intermittent green dashes along the sides

  • Black eye-stripe present

  • Three narrow, black lines present posteriorly
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Photo by Anne Devan-Song permission pending

D. caudolineatus
Striped Bronzeback

  • Lacks the black eye-stripe

  • Lower cheeks and lips are pale yellow

  • Vertebral scales are not enlarged but are narrow
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Photo by Anne Devan-Song permission pending

Taxonomy


Dendrelaphis pictus belongs to Colubridae which . There are three subspecies for this group: Dendrelaphis pictus pictus, Gmelin 1788 , D. p. inornatus, Boulenger 1897 and D.p. intermedius, Mertens 1927b (How et al., 1996)

The systematics of this genus have remained ambiguous and incomplete (Rooijen and Vogel, 2008). Many new species has been isolated for this group from different regions and their mophological descriptions has been updated along the way.

Synonym
Coluber pictus GMELIN in LINNAEUS 1789: 1116
Coluber ahaetulla LINNAEUS 1758 (part., nec Coluber pictus GMELIN 1789)
Coluber boiga LACÉPÈDE 1789 (Name invalidated)
Coluber pictus GMELIN 1789: 1116
Coluber decorus SHAW 1802: 538
Ahaetulla fasciata — LINK 1807 (fide STEJNEGER 1933)
Ahaetulla decorus — GRAY 1825: 208
Dendrophis decorus — FITZINGER 1826: 60
Dendrophis pictus - BOIE 1827: 530
Ahaetulla bellii HARDWICKE & GRAY 1834 (fide ROOIJEN & VOGEL 2008)
Dendrophis picta - SCHLEGEL 1837
Leptophis pictus - CANTOR 1847
Dendrophis picta — DUMÉRIL & BIBRON 1854: 197
Ahaetulla picta - COPE 1861
Dendrophis pictus var. - BOETTGER 1883
Dendrophis pictus — FISCHER 1884: 49
Dendrophis pictus — BOULENGER 1894: 78
Dendorophis (sic) pictus, forma typica - COHN 1905
Dendrophis pictus — WALL 1907: 189
Dendrophis proarchos WALL 1909
Dendrelaphis proarchos — WALL 1909
Dendrophis proarchus (sic) — WALL 1921:157
Dendrophis pictus — DE ROOIJ 1917: 58
Ahaetulla boiga - SCHMIDT 1927: 445
Ahaetulla boiga boiga — MERTENS 1930
Dendrophis pictus pictus - BRONGERSMA 1931
Dendrophis boiga - STEJNEGER 1933
Dendrelaphis pictus pictus - MERTENS 1934
Dendrophis pictus pictus — KOPSTEIN 1938
Ahaetulla boiga boiga - LADIGES 1939
Ahaetulla ahaetulla - SMITH 1943: 242
Ahaetulla picta picta - HAAS 1950
Dendrelaphis (boiga) -SAVAGE 1952
Dendrelaphis pictus - TWEEDIE 1983
Dendrelaphis pictus — MANTHEY & GROSSMANN 1997: 338
Dendrelaphis pictus — COX et al. 1998: 71
Dendrelaphis pictus pictus — GAULKE 1999
Dendrelaphis pictus — VOGEL & VAN ROOIJEN 2011
Dendrelaphis proarchos — VOGEL & VAN ROOIJEN 2011

Pet trade


This beautiful creature is very adaptable to wide range of habitat thus making it a popular subject for pet trade. Their abundance in Southeast Asia has also made them vulnerable to poachers. They can be easily found on online shops and many of the times they are sold out!!

Due to the unavailability of natural food resources, many of the keepers have to switch the diet of their snakes from frogs an lizards to rodent and worms. Snakes which do not prefer their new diet have to be force-feed which may be dangerous and easily cause injuries on snakes.



Force feeding of a snake
Green tree snake was feed using wax worm

References


Caroline Camilleri and Richard Shine, 1990. Sexual dimorphism and dietary divergence: differences in trophic morphology between male and female snakes, Copeia 3: 649-658

T. Chan-ard, W. Grossmann, A. Gumprecht, K.-D. Schultz, 1999, Amphibians and Reptiles of Peninsular Malaysia and Thailand. An illustrated checklist, Wuerselen, Germany, Bushmaster publications

J. C. Daniel, 2002, The book of Indian Reptiles and Amphibians, Oxrford University Press

Nicholson Edward ,1874, Indian snakes: an elementary treatise on ophiology with a descriptive catalogue of the snakes found in India and the adjoining countries, Madras: Higginbotham
Harry W. Greene, Michael Fogden and Patricia Fogden,1997, Snakes: The Evolution of Mystery in Nature, University of California Press

R.A. How, L.H. Schmitt and Maharadatunkamsi, 1996, Geographical variation in the gnus Dendrelaphis (Serpentes: Colubridae) within the islands of south-eastern Indonesia, Journal of Zoology 238: 351-363

T.M. Leong, C. Yeong and R. Subaraj, 2009, Attempted predation on a tadpole by a Painted Bronzeback Dendrelaphis pictus (Reptilia: Squamata: Colubridae), Nature in Singapore 2:361-364

F.L.K. Lim and M.T.M. Lee, 1989, Fascinating snakes of Southeast Asia - An Introduction. Kuala Lumpur, Tropical Press.

R.B. Stuebing and R.F. Inger, 1999, A field Guide to the Snakes of Borneo. Kota Kinabalu, Natural History Publications

J. van Rooijen and G. Vogel, 2008. Contributions to a review of the Dendrelaphis puctus complex (Serpentes:Colubridae)-1. Description of a sympatric species, Amphibian-Reptilia 28:101-115

Richard Shine, 1978. Sexual size dimorphism and male comat in snakes. Oecologia 33:269-277