Discarded drink cans- a threat to curious monitor lizard Varanus acanthurus (Boulenger, 1885)

Abstract

Monitor lizards are reptiles belonging to the monogenous family Varanidae, comprising 81 species. Varanids are a small but diverse group of lizards. They play an important role in ecosystems as predators, scavengers and creators of microhabitats for other animals. IUCN Red List includes 53 species, which shows that they require protection. Currently, many types of anthropogenic threat affecting local populations of monitor lizards.

Ridgetail Monitor (Varanus acanthurus) listed as "Least Concern" according to the IUCN Red List. We obtained 7 cases of Varanus Acanthurus stuck in a discarded drink can from Australia from scientists and naturalists who study or observe monitor lizards, respectively. Mostly, they were rescued by an observer or transported to the wildlife rescue. 3 have been found dead.

The rarely discussed threat is getting stuck in a discarded drink can. The animals put their heads in a container or fully enter it in order to eat food scraps or other animals that have remained there stuck before. However, to take the head out of the container is a problem, and such an incident is often fatal.

Despite the need to implement strict law and regulations regarding littering and waste disposal, to minimize the amount of litter in the environment, garbage bins should be installed along hiking path and be emptied regularly, and clean-up actions engaging local communities should be organised periodically. However, due to the rarity of observations mentioned above, the actual effect of discarded cans on varanid populations remains poorly understood. It is also encouraging that part of society see the problem of varanid mortality in discarded cans or, if possible, even try to save them. Taking into consideration reports presented herein, we strongly encourage conservationists to pay attention to this issue.

Full text

Canettes de boisson jetées - une menace pour le curieux Varan à
queue épineuse Varanus acanthurus (Boulenger, 1885)
OBSERVATIONS
Nous avons rassemblé 7 cas de Varanus acanthurus coincés dans une
canette de boisson. La plupart du temps, ils ont été secourus par un
observateur ou transportés au centre de soins de la faune sauvage. 3 ont été
retrouvés morts. Toutes les observations realisées par les scientifiques et
naturalistes ont été faites en Australie.
REFERENCES
Arida, E., Hidayat, A., Mulyadi, Maireda, N.L., Subasli, D.R. and Mumpuni 2020. Consumption and Trade of Asian Water Monitor, Varanus salvator as Reliance on Wildlife for Livelihoods among Rural Communities in North Sumatra, Indonesia. Journal of tropical ethnobiology 3(2):81-92
Ariefiandy, A., Purwandana, D., Azmi, M., Nasu, S.A., Mardani, J., Ciofi, C. and Jessop, T.S. 2021. Human activities associated with reduced Komodo dragon habitat use and range loss on Flores. Biodiversity and Conservation 30(1)
Auliya, M. and Koch, A. 2020. Visual identification guide for the monitor lizard species of the world (Genus Varanus) guidance for the identification of monitor lizards with current distribution data as well as short explanations on reproductive characteristics and captive breeding to support CITES authorities. Bonn, Germany: Federal Agency for Nature Conservation.
Azmi, M, Ardiantiono,, Nasu, SA, Kasim, AM, Ariefiandy, A, Purwandana, D, Ciofi, C and Jessop, T. 2021. Incidences of Road Kills and Injuries of Komodo Dragons Along the North Coast of Flores Island, Indonesia, Herpetological Conservation and Biology, 16(1):11-15
Bhattacharya, S. and A. Koch. 2018. Effects of traditional beliefs leading to conservation of Water Monitor Lizards (Varanus Salvator) and threatened marshlands in West Bengal, India. Herpetological Conservation and Biology 13:408–414
Cochrane, J. 2013. Exit the Dragon? Collapse of Co-management at Komodo National Park, Indonesia. Tourism Recreation Research 35(2): 127-143
Duengkae, P. and Chuaynkern, Y. 2009. A Road-killed Water Monitor Varanus salvator macromaculatus: Negative Impact from the Forest Route in Khao Yai National Park, Thailand. Biwak 3(1):23-25
Englefield, B., Starling, M. J., Wilson, B.J., Roder, C. and McGreevy, P.D. 2020. The Australian Roadkill Reporting Project- Applying Integrated Professional Research and Citizen Science to Monitor and Mitigate Roadkill in Australia. Animals 10(7):1112
Gillet, A and Jackson, R. 2010. Human food scrap ingestion in two wild lace monitors Varanus varius. Biawak 4(3): 99-102.
Jessop, T.S., A. Ariefiandy, D.M. Forsyth, D. Purwandana, C.R. White, Y.J. Benu, T. Madsen, H.J. Harlow, and M. Letnic. 2020. Komodo Dragons are not ecological analogs of apex mammalian predators. Ecology 101: e02970. https://doi.org/10.1002/ecy.2970
Jessop, T.S., A. Ariefiandy, D. Purwandana, Y.J. Benu, M. Hyatt, and M. Letnic. 2019. Little to fear: largest lizard predator induces weak defense responses in ungulate prey. Behavioral Ecology 30:624–636.
Jones, A.R., Jessop, T.S., Ariefiandy, A., Brook, B.W., Brown, S.C., Ciofi, C., Benu, Y.J., Purwandana, D., Sitorus, T., Wigley, T.M.L. and Fordham, D.A. 2020. Identifying island safe havens to prevent the extinction of the World's largest lizard from global warming. Ecology and Evolution 10:10492–10507
Karunarathna, D.M.S.S., Amarasinghe, A.A.T., Madawala, M.B., Kandambi, H.K.D. 2012. Population status of two Varanus species (Reptilia: Sauria: Varanidae) in Sri Lanka’s Puttalam lagoon system, with notes on their diet and conservation status. Biawak 6(1):22–33
Karunarathna, D.M.S.S., Surasinghe, T.D., Dissanayake, D., Botejue, M., Gabadage, D. and Madawale, M.B. 2017. Dietary habits and the predators of the Bengal monitor Varanus bengalensis in Sri Lanka. Biawak 11(1):28–39
Kulabtong, S., Mahaprom, R. 2015. Observation on food items of Asian water monitor, Varanus salvator (Laurenti, 1768) (Squamata Varanidae), in urban ecosystem, Central Thailand. Biodiversity Journal, 6 (3):695–698
Koch, A., Ziegler, T., Bohme, W., Arida, E. and Auliya, M. 2013. Distribution, threats, and conservation status of the monitor lizard (Varanidae: Varanus ssp.) of Southern Asia and the Indo-Australian achipelago. Herpetological Conservation and Biology, 8(3):1–62
Kolenda, K., Pawlik, M., Kuśmierek, N., Smolis, A. and Kadej, M. 2021. Online media reveals a global problem of discarded containers as deadly traps for animals. Scientific Reports 11(1):267
Miranda, E.B.P. 2017. The Plight of Reptiles as Ecological Actors in the Tropics. Frontiers in Ecology and Evolution 5(159)1:15
Nijman, V. 2015. Water monitor lizards for sale as novelty food in Java, Indonesia. Biawak 9(1):28–32
Rahman, K.M.M., Khan, M.M.H. and Rakhomov I.I. 2015. Scavenging Behavior of the Bengal Monitor (Varanus bengalensis) in Jahangirnagar University Campus, Bangladesh. Journal of Scientific Research & Reports 7(7):539-550
Shadloo, S., Mahmoodi, S., Hosseinzadeh, M.S., Kazemi, S.M. 2021. Prediction of habitat suitability for the desert monitor (Varanus griseus caspius) under the influence of future climate change. Journal of Arid Environments 186:104416
Shea, G. and Cogger, H. 2018. Varanus acanthurus. The IUCN Red List of Threatened Species 2018: e.T83777229A101752285. https://dx.doi.org/10.2305/IUCN.UK.2018-1.RLTS.T83777229A101752285.en. Downloaded on 12 July 2021.
Shine, R., Harlow, P.S. and Keogh, J.S. 1996. Commercial harvesting of giant lizards: The biology of water monitors Varanus salvator in southern Sumatra. Biological Conservation 77:125–134
Shine, R. and Koenig, J. 2001. Snakes in the garden: an analysis of reptiles ‘‘rescued’’ by community-based wildlife carers. Biological Conservation 102:271–283
Trembath, D. and Freier, D. 2005. Accidental ingestion of barbecue scraps leads to death of a varanid in the Northern Territory. Herpetofauna 35:48–49
Uyeda, L.T., Iskandar, E., Purbatrapsila, A., Pamungkas, J., Wirsing, A. and Kyes, R. 2014. Water monitor lizard (Varanus salvator) satay: A treatment for skin ailments in Muarabinuangeun and Cisiih, Indonesia. Biawak 8(1):35–38
Zdunek, P. W krainie ostatnich żyjących smoków. Salamandra, 2019, 1-2(47): 44-47
ZDUNEK Przemysław 1,3 & KOLENDA Krzysztof 2
1 L'Association du Refuge des Tortues (A.R.T.), 2920 Route de Paulhac, 31660 Bessieres, France; zdunek.komodo@gmail.com
2 Department of Evolutionary Biology and Conservation of Vertebrates, Institute of Environmental Biology, University of Wrocław, Sienkiewicza 21, 50-335 Wrocław,
Poland; krzysztof.kolenda@uwr.edu.pl
3 NATRIX Herpetological Association, ul. Opolska 41/1, 52-010 Wrocław, Poland;
INTRODUCTION
Les varans sont des reptiles appartenant à la famille
monogenre des Varanidae, comprenant 81 espèces,
parmi lequel est inclus le plus grand lézard vivant, le
dragon de Komodo (Varanus komodoensis). Les
moniteurs sont un petit groupe de lézards mais qui est
très diversifié. Ils jouent un rôle important dans les
écosystèmes en tant que prédateurs, charognards et
créateurs de microhabitats pour d'autres animaux. La
liste rouge de l'UICN comprend 68 espèces de
varans, ce qui montre qu'elles nécessitent une
protection.
Actuellement, voici les menaces anthropiques majeures
affectant les populations locales de varans (Table 1.)
Le Varan à queue épineuse (Varanus acanthurus) est
répertorié comme "Préoccupation mineure" selon la liste
rouge de l'UICN, ce qui montre qu'il a besoin d'être
protégé.
Il est bien connu que de nombreux varans exploitent les
habitats urbains, en particulier les décharges, qui sont
considérés comme des sources de nourriture. Cependant,
se nourrir de déchets alimentaires anthropiques peut
entraîner des blessures internes et par conséquent une mort
lente.
Une menace rarement abordée est le risque de rester coincé
dans une canette de boisson. Les lézards mettent leur tête
dans une canette ou y pénètrent complètement afin de
manger des restes de nourriture ou d'autres animaux qui y
sont restés coincés auparavant. Ils sont néanmoins de
grandes difficultés à en sortir la tête, et un tel incident est
souvent fatal.
48e CONGRÈS
DE LA SOCIÉTÉ HERPÉTOLOGIQUE DE FRANCE
21 - 23 octobre 2021 Lille
CONCLUSION
Il y a donc nécessité de mettre en œuvre des lois et des
réglementations strictes concernant les déchets et
l'élimination des déchets, afin d’en minimiser le nombre
dans l'environnement. Des poubelles doivent être installées
le long des sentiers de randonnée et être vidées
régulièrement, et des actions de nettoyage impliquant les
communautés locales doivent être organisées
régulièrement.
Cependant, en raison de la rareté des observations
mentionnées ci-dessus, l'effet réel des canettes jetées sur les
populations de varanides reste mal compris. Il est également
encourageant de constater qu'une partie de la société est
sensible à ce problème et tente, si possible, de les sauver.
Compte tenu des rapports présentés ici, nous encourageons
fortement les écologistes à prêter attention à cette
question.
REMERCIEMENTS
Nous tenons à remercier Brian
Bush, Owen Gale, Zig
Madycki, Rex Neindorf et
ExplorOz Team, pour avoir
partagé leurs observations de
varans et pour la permission
d'utiliser leurs photographies.
Aussi Antony Martinez et
Adèle Vantorhoudt pour leur
aide dans l'édition du texte.
Table 1. MENACES ACTUELLES
Dégradation de leurs habitats naturels
(Koch et al., 2013; Ariefiandy et al., 2021)
Tourisme incontrôlé
(Cochrane, 2013; Zdunek, 2019)
Trafic d'animaux
(Koch et al., 2013; Zdunek, 2019)
Mortalité routière
(Englefield et al., 2020; Karunarathna et al., 2012; Duengkae and Chuaynkern, 2009; Amzi et al., 2021)
Commerce de viande pour la consommation
(Nijman, 2015)
Trafic de peaux pour l'industrie du cuir
(Arida et al., 2020; Shine et al., 1996)
Réchauffement climatique progressif
(Shadloo et al., 2021; Jones et al., 2020)
Remède dans le traitement traditionnel
(maladies de la peau, eczéma, asthme, cécité et comme aphrodisiaque)
(Bhattacharya and Koch, 2018; Uyeda et al., 2014; Zdunek, 2019)
Mots-clés: Varanus acanthurus, conservation de l'espèce, piège écologique, Varanidae, espèce menacée

Cite: Zdunek, P., Kolenda, K. 2021. Discarded drink cans- a threat to curious monitor lizard Varanus acanthurus (Boulenger, 1885).
48th Congress of The Society Herpetological of France, 21-23 october 2021, Lille, France
Discarded drink cans- a threat to curious monitor lizard Varanus acanthurus
(Boulenger, 1885)
Przemysław Zdunek1,3, Krzysztof Kolenda2
1Association de protection du Refuge des Tortues (A.R.T.), 2920 Route de Paulhac, 31660 Bessières, France;
e-mail: zdunek.komodo@gmail.com
2 Department of Evolutionary Biology and Conservation of Vertebrates, Institute of Environmental Biology, University
of Wrocław, Sienkiewicza 21, 50-335, Wrocław, Poland;
e-mail: krzysztof.kolenda@uwr.edu.pl
3NATRIX Herpetological Association, ul. Opolska 41/1, 52-010 Wrocław, Poland;
Abstract. Monitor lizards are reptiles belonging to the monogenous family Varanidae, comprising
81 species. Varanids are a small but diverse group of lizards. They play an important role in
ecosystems as predators, scavengers and creators of microhabitats for other animals. IUCN Red List
includes 53 species, which shows that they require protection. Currently, many types of
anthropogenic threat affecting local populations of monitor lizards.
Ridgetail Monitor (Varanus acanthurus) listed as "Least Concern" according to the IUCN
Red List. We obtained 7 cases of Varanus Acanthurus stuck in a discarded drink can from Australia
from scientists and naturalists who study or observe monitor lizards, respectively. Mostly, they were
rescued by an observer or transported to the wildlife rescue. 3 have been found dead.
The rarely discussed threat is getting stuck in a discarded drink can. The animals put their
heads in a container or fully enter it in order to eat food scraps or other animals that have remained
there stuck before. However, to take the head out of the container is a problem, and such an incident
is often fatal.
Despite the need to implement strict law and regulations regarding littering and waste
disposal, to minimize the amount of litter in the environment, garbage bins should be installed along
hiking path and be emptied regularly, and clean-up actions engaging local communities should be
organised periodically. However, due to the rarity of observations mentioned above, the actual
effect of discarded cans on varanid populations remains poorly understood. It is also encouraging
that part of society see the problem of varanid mortality in discarded cans or, if possible, even try to
save them. Taking into consideration reports presented herein, we strongly encourage
conservationists to pay attention to this issue.
ACKNOWLEDGMENTS
We would like to thank Brian Bush, Owen Gale, Zig Madycki, Rex Neindorf and ExplorOz Team,
for sharing their monitor lizard sightings and for permission to use their photographs. Also Antony
Martinez and Adèle Vantorhoudt for their help in editing the text.

Canettes de boisson jetées- une menace pour le curieux Varan à queue épineuse Varanus
acanthurus (Boulenger, 1885)
Résumé. Les varans sont des reptiles appartenant à la famille monogenre des Varanidae,
comprenant 81 espèces, parmi lequel est inclus le plus grand lézard vivant, le dragon de Komodo
(Varanus komodoensis). Les moniteurs sont un petit groupe de lézards mais qui est très diversifié.
Ils jouent un rôle important dans les écosystèmes en tant que prédateurs, charognards et créateurs de
microhabitats pour d'autres animaux. La liste rouge de l'UICN comprend 68 espèces de varans, ce
qui montre qu'elles nécessitent une protection. Actuellement, menace anthropique majeure affectant
les populations locales de varans.
Le Varan à queue épineuse (Varanus acanthurus) est répertorié comme "Préoccupation
mineure" selon la liste rouge de l'UICN. Nous avons rassemblé 7 cas de Varanus acanthurus
coincés dans une canette de boisson. La plupart du temps, ils ont été secourus par un observateur ou
transportés au centre de soins de la faune sauvage. 3 ont été retrouvés morts. Toutes les observations
realisées par les scientifiques et naturalistes ont été faites en Australie.
Une menace rarement abordée est le risque de rester coincé dans une canette de boisson. Les
lézards mettent leur tête dans une canette ou y pénètrent complètement afin de manger des restes de
nourriture ou d'autres animaux qui y sont restés coincés auparavant. Ils sont néanmoins de grandes
difficultés à en sortir la tête, et un tel incident est souvent fatal.
Il y a donc nécessité de mettre en œuvre des lois et des réglementations strictes concernant
les déchets et l'élimination des déchets, afin d’en minimiser le nombre dans l'environnement. Des
poubelles doivent être installées le long des sentiers de randonnée et être vidées régulièrement, et
des actions de nettoyage impliquant les communautés locales doivent être organisées régulièrement.
Cependant, en raison de la rareté des observations mentionnées ci-dessus, l'effet réel des canettes
jetées sur les populations de varanides reste mal compris. Il est également encourageant de constater
qu'une partie de la société est sensible à ce problème et tente, si possible, de les sauver. Compte tenu
des rapports présentés ici, nous encourageons fortement les écologistes à prêter attention à cette
question.
REMERCIEMENTS
Nous tenons à remercier Brian Bush, Owen Gale, Zig Madycki, Rex Neindorf et ExplorOz Team,
pour avoir partagé leurs observations de varans et pour la permission d'utiliser leurs photographies.
Aussi Antony Martinez et Adèle Vantorhoudt pour leur aide dans l'édition du texte.
REFERENCES
Arida, E., Hidayat, A., Mulyadi, Maireda, N.L., Subasli, D.R. and Mumpuni 2020. Consumption
and Trade of Asian Water Monitor, Varanus salvator as Reliance on Wildlife for Livelihoods among
Rural Communities in North Sumatra, Indonesia. Journal of tropical ethnobiology 3(2):81-92
Ariefiandy, A., Purwandana, D., Azmi, M., Nasu, S.A., Mardani, J., Ciofi, C. and Jessop, T.S. 2021.
Human activities associated with reduced Komodo dragon habitat use and range loss on Flores.
Biodiversity and Conservation 30(1)
Auliya, M. and Koch, A. 2020. Visual identification guide for the monitor lizard species of the
world (Genus Varanus) guidance for the identification of monitor lizards with current distribution
data as well as short explanations on reproductive characteristics and captive breeding to support
CITES authorities. Bonn, Germany: Federal Agency for Nature Conservation.
Azmi, M, Ardiantiono,, Nasu, SA, Kasim, AM, Ariefiandy, A, Purwandana, D, Ciofi, C and Jessop,
T. 2021. Incidences of Road Kills and Injuries of Komodo Dragons Along the North Coast of Flores

Island, Indonesia, Herpetological Conservation and Biology, 16(1):11-15
Bhattacharya, S. and A. Koch. 2018. Effects of traditional beliefs leading to conservation of
Water Monitor Lizards (Varanus Salvator) and threatened marshlands in West Bengal, India.
Herpetological Conservation and Biology 13:408–414
Cochrane, J. 2013. Exit the Dragon? Collapse of Co-management at Komodo National Park,
Indonesia. Tourism Recreation Research 35(2): 127-143
Duengkae, P. and Chuaynkern, Y. 2009. A Road-killed Water Monitor Varanus salvator
macromaculatus: Negative Impact from the Forest Route in Khao Yai National Park, Thailand.
Biwak 3(1):23-25
Englefield, B., Starling, M. J., Wilson, B.J., Roder, C. and McGreevy, P.D. 2020. The Australian
Roadkill Reporting Project- Applying Integrated Professional Research and Citizen Science to
Monitor and Mitigate Roadkill in Australia. Animals 10(7):1112
Gillet, A and Jackson, R. 2010. Human food scrap ingestion in two wild lace monitors Varanus
varius. Biawak 4(3): 99-102.
Jessop, T.S., A. Ariefiandy, D.M. Forsyth, D. Purwandana, C.R. White, Y.J. Benu, T. Madsen, H.J.
Harlow, and M. Letnic. 2020. Komodo Dragons are not ecological analogs of apex mammalian
predators. Ecology 101: e02970. https://doi.org/10.1002/ecy.2970
Jessop, T.S., A. Ariefiandy, D. Purwandana, Y.J. Benu, M. Hyatt, and M. Letnic. 2019. Little to fear:
largest lizard predator induces weak defense responses in ungulate prey. Behavioral Ecology
30:624–636.
Jones, A.R., Jessop, T.S., Ariefiandy, A., Brook, B.W., Brown, S.C., Ciofi, C., Benu, Y.J.,
Purwandana, D., Sitorus, T., Wigley, T.M.L. and Fordham, D.A. 2020. Identifying island safe
havens to prevent the extinction of the World's largest lizard from global warming. Ecology and
Evolution 10:10492–10507
Karunarathna, D.M.S.S., Amarasinghe, A.A.T., Madawala, M.B., Kandambi, H.K.D. 2012.
Population status of two Varanus species (Reptilia: Sauria: Varanidae) in Sri Lanka’s Puttalam
lagoon system, with notes on their diet and conservation status. Biawak 6(1):22–33
Karunarathna, D.M.S.S., Surasinghe, T.D., Dissanayake, D., Botejue, M., Gabadage, D. and
Madawale, M.B. 2017. Dietary habits and the predators of the Bengal monitor Varanus bengalensis
in Sri Lanka. Biawak 11(1):28–39
Kulabtong, S., Mahaprom, R. 2015. Observation on food items of Asian water monitor, Varanus
salvator (Laurenti, 1768) (Squamata Varanidae), in urban ecosystem, Central Thailand. Biodiversity
Journal, 6 (3):695–698
Koch, A., Ziegler, T., Bohme, W., Arida, E. and Auliya, M. 2013. Distribution, threats, and
conservation status of the monitor lizard (Varanidae: Varanus ssp.) of Southern Asia and the Indo-
Australian achipelago. Herpetological Conservation and Biology, 8(3):1–62
Kolenda, K., Pawlik, M., Kuśmierek, N., Smolis, A. and Kadej, M. 2021. Online media reveals a
global problem of discarded containers as deadly traps for animals. Scientific Reports 11(1):267

Miranda, E.B.P. 2017. The Plight of Reptiles as Ecological Actors in the Tropics. Frontiers in
Ecology and Evolution 5(159)1:15
Nijman, V. 2015. Water monitor lizards for sale as novelty food in Java, Indonesia. Biawak 9(1):28–
32
Rahman, K.M.M., Khan, M.M.H. and Rakhomov I.I. 2015. Scavenging Behavior of the Bengal
Monitor (Varanus bengalensis) in Jahangirnagar University Campus, Bangladesh. Journal of
Scientific Research & Reports 7(7):539-550
Shadloo, S., Mahmoodi, S., Hosseinzadeh, M.S., Kazemi, S.M. 2021. Prediction of habitat
suitability for the desert monitor (Varanus griseus caspius) under the influence of future climate
change. Journal of Arid Environments 186:104416
Shea, G. and Cogger, H. 2018. Varanus acanthurus. The IUCN Red List of Threatened Species
2018: e.T83777229A101752285.
https://dx.doi.org/10.2305/IUCN.UK.2018-1.RLTS.T83777229A101752285.en.
Downloaded on 12 July 2021.
Shine, R., Harlow, P.S. and Keogh, J.S. 1996. Commercial harvesting of giant lizards: The biology
of water monitors Varanus salvator in southern Sumatra. Biological Conservation 77:125–134
Shine, R. and Koenig, J. 2001. Snakes in the garden: an analysis of reptiles ‘‘rescued’’ by
community-based wildlife carers. Biological Conservation 102:271–283
Trembath, D. and Freier, D. 2005. Accidental ingestion of barbecue scraps leads to death of a
varanid in the Northern Territory. Herpetofauna 35:48–49
Uyeda, L.T., Iskandar, E., Purbatrapsila, A., Pamungkas, J., Wirsing, A. and Kyes, R. 2014.
Water monitor lizard (Varanus salvator) satay: A treatment for skin ailments in
Muarabinuangeun and Cisiih, Indonesia. Biawak 8(1):35–38
Zdunek, P. W krainie ostatnich żyjących smoków. Salamandra, 2019, 1-2(47): 44-47