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Abnormalities in reptiles have been mostly reported from captive individuals. Here, we report a case of unilateral anophthalmy in the Burmese python Python bivittatus for the first time from Chitwan National Park, Nepal. Reptiles exposed to various pollutants, such as pesticides, can develop morphological abnormalities. The present report from a human-dominated landscape is an opportunistic observation of a rescued snake. We suggest a more systematic, collection-based, research program to reveal the possible causative agents and the degree of their effect on herpetofauna in Nepal.
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Journal of Animal Diversity
Volume 3, Issue 1 (2021)
Online ISSN
Short Communication
A case of unilateral anophthalmy in the Burmese python, Python bivittatus
Kuhl, 1820 (Squamata: Pythonidae) from Nepal
Santosh Bhattarai1*, Babu Ram Lamichhane1 and Naresh Subedi2
1National Trust for Nature Conservation-Biodiversity Conservation Center, Ratnanagar-06, Sauraha,
Chitwan-44204, Nepal.
2National Trust for Nature Conservation, Khumaltar, Lalitpur, Nepal
*Corresponding author :
Received: 7 August 2020
Accepted: 17 November 2020
Published online: 31 March 2021
Abnormalities in reptiles have been mostly reported from captive individuals.
Here, we report a case of unilateral anophthalmy in the Burmese python Python
bivittatus for the first time from Chitwan National Park, Nepal. Reptiles exposed to
various pollutants, such as pesticides, can develop morphological abnormalities.
The present report from a human-dominated landscape is an opportunistic
observation of a rescued snake. We suggest a more systematic, collection-
research program to reveal the possible causative agents and the degree of thei
effect on herpetofauna in Nepal.
Key words: Absence of eye, Chitwan National Park, deformity, snake
Morphological abnormalities are commonly
reported in herpetofauna across the world including
congenital malformations in snakes, mainly related
to osteological deformities (Khan and Law, 2005;
Sant'Anna et al., 2013; Da Silva et al., 2015; Mester
et al., 2015). In reptiles, the congenital deformities
are induced during the period of early
developmental stage in the egg, possibly due to
exposure of the developing embryo to abnormal
temperature, nutritional deficiencies, toxins or
infectious agents (Sabater and Pérez, 2013; Da
Silva et al., 2015; Mingo et al., 2016).
Anophthalmy is the absence of one or both eyes, and
the position of the affected eye may differ from
individual to individual (Jablonski and Mikulíček,
2015). In snakes, most of the cases of anopthalmy
have been reported from captive bred individuals, (e.g.
the Rainbow Boa Epicrates cenchria (Linnaeus),
Eastern Pine snake Pituophis melanoleucus (Daudin),
Burmese Python Python bivittatus Kuhl, Ball Python
Python regius (Shaw), Nose-horned Viper Vipera
ammodytes (Linnaeus) (Heimes, 1994; Sabater and
Pérez, 2013; Da Silva et al., 2015). More recently,
Jablonski and Mikulíček (2015) reported a
unilateral anophthalmia in Coronella austriaca
Laurenti from Šúr Nature Reserve near Bratislava
in south-western Slovakia. In Nepal, both
dicephalism abnormalities (two heads) in the
Common Krait, Bungarus caeruleus (Schneider
1801) and in the Banded Kukri, Oligodon arnensis
(Shaw 1802) (Devkota et al., 2020 a, b) and tail
bifurcation in the Yellow-bellied House Gecko,
Hemidactylus flaviviridis (see Bhattarai et al.,
2020) have been recorded.
Human-python conflict is frequently observed in the
buffer zone around the Chitwan National Park, but it
is not well documented (Bhattarai et al., 2017). This
case of anophthalmy in a Burmese Python, Python
bivittatus, was observed during its rescue from
Sauraha village in the buffer zone of Chitwan
National Park (CNP). To date, anophthalmia has not
been reported for any herpetofauna species from
Nepal and so here we report the first case of
unilateral anophthalmy in a Burmese python from
the buffer zone of Chitwan National Park.
The CNP (952.63 km2) is the oldest National Park
in Nepal, established in 1973 and it is a World
Heritage Site, situated along the foothills of the
Himalayas (Fig. 1). The Park has global significance
This article is published with open access on | © Lorestan University Pressss
Santosh Bhattarai et al. 7
Journal of Animal Diversity (2021) | © Lorestan University
with a high diversity of flora and fauna. Due to the
high density of wildlife in the CNP, some of the
wildlife is pushed out into the fringe areas and
sometimes inside adjacent human settlements. Such
animals are required to be rescued promptly to save
their life and reduce the threat to local people.
Figure 1: Map showing location of the Chitwan National Park, Nepal and rescue location of the anophthalmic
Burmese python, Python bivittatus.
Annually, over 100 animals are rescued in the
proximity of the CNP. The National Trust for
Nature Conservation – Biodiversity Conservation
Center (NTNC-BCC) situated in the eastern sector
of the CNP, supports the CNP in rescue and
management of such vagrant wildlife, including:
Bengal tiger Panthera tigris (Linnaeus), Greater
one-horned rhino, Rhinoceros unicornis (Linnaeus),
Common leopard Panthera pardus (Linnaeus),
mugger crocodile, Crocodylus palustris (Lesson),
Gharial, Gavialis gangeticus (Gmelin) and other
smaller animals including snakes. The NTNC-BCC
rescued 62 individuals of reptiles from January to
July, 2020 (Table 1). The first author inspected all
the rescued reptiles and released them to the wild.
During one inspection, a single case of unilateral
anophthalmy was detected in a sub-adult Burmese
python. It was rescued from the kitchen of a house
on 23 June 2020 and brought to the NTNC-BCC.
The abnormal individual was photographed,
morphometric measurements taken with the aid of a
measuring tape and then it was released into the
wild in Chitwan National Park. We also made
inquiries of snake researchers, conservationists and
rescuers (n=12) about such anophthalmic case
previously observed in Nepal.
Table 1: List of rescued reptile species from January 2020 to July 2020 from the buffer zone of the Chitwan
National Park, Nepal.
Common name Scientific name Number of specimens
Burmese python Python bivittatus Kuhl 35
Siamese cat snake Boiga siamensis Nutaphand 2
Common wolf snake Lycodon aulicus (Linnaeus) 1
Twin spotted wolf snake Lycodon jara (Shaw) 2
Common Kukri snake Oligodon arnensis (Shaw) 2
Banded krait Bungarus fasciatus (Schneider) 2
Bronze backed tree snake Dendrelaphis tristis (Daudin) 2
Checkered keelback Fowlea piscator (Schneider) 1
Rat snake
tyas mucosa (Linnaeus) 4
Common trinket snake Coelognathus helena (Daudin) 1
Copper-headed trinket snake Coelognathus radiatus (Boie) 2
Ornate flying snake Chrysopelea ornata (Shaw) 4
Golden monitor lizard Varanus flavescens (Hardwicke and Gray) 1
Peacock soft-shell turtle Nilssonia hurum (Gray) 1
Mugger crocodile Crocodylus palustris (Lesson) 2
Total 62
A case of unilateral anophthalmy in the Burmese python…
Journal of Animal Diversity (2021), 3 (1): 6–10 | 8
The sub-adult individual (total length 260 cm,
Snout-vent length (SVL) 225 cm, tail length (TL)
35 cm, weight 6.1 kg) lacked the left eye, but apart
from this malformation had no other apparent
physical injury or old scars (Fig. 2). The
abnormality of the left eye appeared as if the eye
had popped out or failed to develop and appeared to
be a congenital problem as the left eye region was
covered with additional scales (Fig. 3A). The right
eye of the snake (Fig. 3B), however, was normally
We did not find other anophthalmic cases from
rescued reptiles in this area. However, after
enquiries with snake researchers, conservationists
and rescuers we identified a single record of
anophthalmia in a Many-banded cat-snake or
Himalayan cat-snake, Boiga multifasciata (Blyth)
from Chhomrung village of Annapurna
Conservation Area in 2003 (Karan Bahadur Shah,
pers. comm.); which is ca. 125 km north of the
current observation site.
In reptiles, various congenital disorders such as
microphthalmia, anophthalmia, cystic globe,
cyclopia/synophthalmia, coloboma or aphakia and
teratogenic lesions have been reported and such
disorders can occur during organogenesis or after
organogenesis during tissue differentiation
(Wallach, 2007; Sabater and Pérez, 2013; Jablonski
and Mikulíček, 2015; Garcês et al., 2020). Da Silva
et al. (2015) reported seven cases of unilateral
microphthalmia and anophthalmia in Python
bivittatus and one case in the Ball python P. regius
in captive-bred individuals. However, no
authenticated reports of such abnormalities in P.
bivittatus were documented from wild populations.
This unilateral anophthalmy in the wild individual
of P. bivittatus is likely due to exposure to various
types of toxic compounds in the human-modified
landscape where extensive use of pesticides is
common. Therefore, it is possible that the increased
use of pesticides in agriculture in the vicinity of the
CNP might have attributed to this unilateral
anophthalmy in P. bivittatus. However, the true
cause of this malformation is not known.
The Burmese python is one of the most charismatic
snakes of the CNP and is the only snake which has
been listed with the highest degree of protection
under the National Parks and Wildlife Conservation
Act, 1973 of Nepal (Bhattarai et al., 2018; Rawat et
al., 2020). Further studies are suggested to
investigate the effects of hazardous pollutants on
reptilian populations in Nepal.
Figure 2: Dorsolateral view of the entire specimen of a unilateral anophthalmic individual of Python bivittatus
from Chitwan National Park, Nepal.
Santosh Bhattarai et al. 9
Journal of Animal Diversity (2021) | © Lorestan University
Figure 3: A unilateral anophthalmic individual of Python bivittatus from Chitwan National Park, Nepal: Left
frontolateral view of head showing the malformed eye (A); right lateral view of head with normal eye (B).
A case of unilateral anophthalmy in the Burmese python…
Journal of Animal Diversity (2021), 3 (1): 6–10 | 10
We would like to thank the wildlife technicians Dip
Prasad Chaudhary, Tika Ram Tharu, Om Prakash
Chaudhary, Ramesh Darai, Binod Darai, Tirth Lama,
Kapil Pokharel, Surendra Chaudhary, Lal Bahadur
Mahatara and Narayan Shrestha of the National Trust
for Nature Conservation-Biodiversity Conservation
Center (NTNC-BCC), Sauraha, Chitwan, Nepal for
assisting rescue operations and management of the
rescued animal. Finally, we appreciate the anonymous
reviewers for their valuable suggestions and
comments on the manuscript.
Conflict of interest
All the authors declare that there are no conflicting
issues related to this short communication.
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ResearchGate has not been able to resolve any citations for this publication.
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