Big-scaled Whipsnake (Chironius grandisquamis)

Reptiles of Ecuador | Serpentes | Colubridae | Chironius grandisquamis

English common names: Big-scaled Whipsnake, Big-scaled Sipo, Ecuador Sipo, Ebony Keelback.

Spanish common names: Chonta (Ecuador); lomo de machete, juetiadora, chonta (Colombia); mica (Costa Rica), zopilota (Panamá).

Recognition: ♂♂ 271.8 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=181.3 cm. ♀♀ 251 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=156.4 cm..^1–3 Chironius grandisquamis can be differentiated from other colubrids by having 10 rows of dorsal scales at mid-body and keeled paravertebral scales, with the remaining dorsal scales smooth.^1–3 This species exhibits an ontogenetic shift in its coloration. Juveniles have a brown dorsum with white or cream bands. Adults display a uniformly black dorsal coloration (Fig. 1), with the anterior portion of the venter white and the posterior black, with some individuals (Ecuadorian specimens) being totally black.^1–3 Chironius grandisquamis is frequently confused with Clelia clelia and Spilotes megalolepis, but it is easily differentiated from these two by having a low number of dorsal scale rows.^1–4

Figure showing variation among individuals of Chironius grandisquamis

Figure 1: Individuals of Chironius grandisquamis from Ecuador: Kapari Lodge, Pichincha province (); Cerro de Hayas, Guayas province ().

Natural history: Chironius grandisquamis is a diurnal and semi-arboreal snake that inhabits old-growth rainforests, gallery forests, pastures, and plantations.^2–4 At night, Big-scaled Whipsnakes sleep on bushes and tree branches at a height of up to 5 m above the ground, usually near or above water bodies.^2,3,5 During daytime, they can be found actively foraging on the forest floor, along river banks, or resting on bushes over streams.^1,2,4 Their diet is composed mainly of amphibians (Bolitoglossa, Leptodactylus, Pristimantis, and Strabomantis),⁶ but also includes birds, lizards, and small mammals.^1–4 There are recorded instances of predation on members of this species by the mussurana Clelia clelia.¹ When pursued by a predator, these snakes tend to jump into streams or rivers and then hide among nearby rocks.^2,5,7 When cornered, whipsnakes tend to inflate the neck, open the mouth aggressively, and strike.^8,9 However, these snakes have no venom glands and are harmless to humans. Clutch size in C. grandisquamis consist of five eggs.^2,3

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Conservation: Least Concern Believed to be safe from extinction given current circumstances..¹⁰ Chironius grandisquamis is listed in this category on the basis of the species’ wide distribution that includes many protected areas as well as by the localized nature of its threats.¹⁰ The most important danger to Ecuadorian populations is large-scale conversion of rainforest to agricultural fields.^4,10

Distribution: Chironius grandisquamis is widely distributed throughout the lowlands and mountain slopes of Central and South America, ranging from Honduras to western Ecuador (Fig. 2).

Figure 2: Distribution of Chironius grandisquamis in Ecuador. See Appendix 1 for a complete list of the presence localities included in the map.

Etymology: The name Chironius was coined by Leopold Fitzinger in 1826, but likely originated in 1790 with Blasius Merrem, who used the common name “Chiron’s Natter” for Linnaeus’ Coluber carinatus.¹¹ In Greek mythology, Chiron was a centaur reputed for his healing abilities. Likewise, in ancient Greek civilization, sick people hoping for a cure flocked to temples where sacred snakes were carefully tended and presented to the sufferers. Therefore, Chironius likely refers to the healing power of snakes, a belief that lies at the foundation of medicine and crosses many cultures worldwide. The specific epithet grandisquamis comes from the Latin grandis (=large) and squama (=scale), and refers to the large dorsal scales.^1,12

See it in the wild: Big-scaled Whipsnakes can be seen at a rate of about once a week in forested areas throughout their distribution in Ecuador. In the environs of Mindo, these snakes are frequently spotted sleeping on vegetation along rivers at night or foraging at ground level in semi-open areas during the day.

Special thanks to Cheryl Vogt for symbolically adopting the Big-scaled Whipsnake and helping bring the Reptiles of Ecuador book project to life.

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Authors: Laura Gómez-Mesa^aAffiliation: Escuela de Ciencias Aplicadas e Ingeniería, Universidad EAFIT, Medellín, Colombia. and Esteban Garzón-Franco^bAffiliation: Colecciones Biológicas de la Universidad CES (CBUCES), Facultad de Ciencias y Biotecnología, Universidad CES, Medellín, Colombia.

Editor: Alejandro Arteaga^cAffiliation: Khamai Foundation, Quito, Ecuador.

Photographer: Jose Vieira^dAffiliation: Tropical Herping (TH), Quito, Ecuador.^,^eAffiliation: ExSitu, Quito, Ecuador.

How to cite? Gómez-Mesa L, Garzón-Franco E (2024) Big-scaled Whipsnake (Chironius grandisquamis). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: www.reptilesofecuador.com. DOI: 10.47051/CQWI9720

Literature cited:

Dixon JR, Wiest Jr JA, Cei JM (1993) Revision of the Neotropical snake genus Chironius Fitzinger (Serpentes, Colubridae). Museo Regionale di Scienze Naturali di Torino, Torino, 280 pp.
Savage JM (2002) The amphibians and reptiles of Costa Rica, a herpetofauna between two continents, between two seas. The University of Chicago Press, Chicago, 934 pp.
Arteaga A, Bustamante L, Guayasamin JM (2013) The amphibians and reptiles of Mindo. Universidad Tecnológica Indoamérica, Quito, 257 pp.
MECN (2010) Serie herpetofauna del Ecuador: El Chocó esmeraldeño. Museo Ecuatoriano de Ciencias Naturales, Quito, 232 pp.
Rojas-Morales JA, Marín-Martínez M (2022) Living near water: ecological observations on the Ecuador Sipo, Chironius grandisquamis, (Peters 1869) (Serpentes: Colubridae), in the Middle Magdalena River Valley, Colombia. Reptiles & Amphibians 29: 46–51. DOI: 10.17161/randa.v29i1.16026
Roberto IJ, Ramos Souza A (2020) Review of prey items recorded for snakes of the genus Chironius (Squamata, Colubridae), including the first record of Osteocephalus as prey. Herpetology Notes 13: 1–5.
Esteban Garzón-Franco, field observation.
Field notes, Reptiles of Ecuador book project.
Lotzkat S (2014) Diversity, taxonomy, and biogeography of the reptiles inhabiting the highlands of the Cordillera Central (Serranía de Talamanca and Serranía de Tabasará) in western Panama. PhD thesis, Goethe-Universität in Frankfurt am Main, 931 pp.
Wilson LD, Lamar W, Cisneros-Heredia DF, Arredondo JC, Daza J (2015) Chironius grandisquamis. The IUCN Red List of threatened species. Available from: www.iucnredlist.org. DOI: 10.2305/IUCN.UK.2015-4.RLTS.T203281A2762910.en
Merrem B (1790) Beitrage zur Naturgeschichte. Duisburg um Lemgo, Berlin, 141 pp.
Brown RW (1956) Composition of scientific words. Smithsonian Books, Washington D.C., 882 pp.

Appendix 1: Locality data used to create the distribution map of Chironius grandisquamis in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used.

Country	Province	Locality	Source
Colombia	Cauca	"López"	iNaturalist; photo examined
Colombia	Nariño	Reserva Natural El Pangán	iNaturalist; photo examined
Colombia	Nariño	Ricaurte	AMNH 108309; VertNet
Ecuador	Azuay	Uzhcurumi	Arteaga et al. 2013
Ecuador	Cañar	Hidroeléctrica Ocaña	Arteaga et al. 2013
Ecuador	Cañar	Huatacón (lower part)	Arteaga et al. 2013
Ecuador	Carchi	Chical, 3 km SW of	Arteaga et al. 2013
Ecuador	Carchi	Tobar Donoso	Samec & Samec 1988
Ecuador	Carchi	Vía Lita	Arteaga et al. 2013
Ecuador	Cotopaxi	Bosque Privado JDLS	Pellet 2017
Ecuador	Cotopaxi	Las Pampas	Arteaga et al. 2013
Ecuador	El Oro	Cerro Azul	Arteaga et al. 2013
Ecuador	El Oro	Piñas	Arteaga et al. 2013
Ecuador	El Oro	Reserva Biológica Buenaventura	Arteaga et al. 2013
Ecuador	El Oro	Zaracay	iNaturalist; photo examined
Ecuador	Esmeraldas	Alrededores de Caimito	Torres-Carvajal et al. 2018
Ecuador	Esmeraldas	Bilsa Biological Reserve	Ortega-Andrade et al. 2010
Ecuador	Esmeraldas	Cerro Ceibo	Arteaga et al. 2013
Ecuador	Esmeraldas	Durango	Torres-Carvajal et al. 2018
Ecuador	Esmeraldas	Jesús del Gran Poder	iNaturalist; photo examined
Ecuador	Esmeraldas	Muisne–Pedernales	Arteaga et al. 2013
Ecuador	Esmeraldas	Playa de Oro	Dixon et al. 1993
Ecuador	Esmeraldas	Playón de San Francisco	Torres-Carvajal et al. 2018
Ecuador	Esmeraldas	Reserva Tesoro Escondido	iNaturalist; photo examined
Ecuador	Esmeraldas	Río Santiago	Arteaga et al. 2013
Ecuador	Esmeraldas	Río Sapayo	Dixon et al. 1993
Ecuador	Esmeraldas	Tundaloma Lodge	Torres-Carvajal et al. 2018
Ecuador	Guayas	Cerro de Hayas	Cruz-García et al. 2020
Ecuador	Guayas	Cerro El Mango	Arteaga et al. 2013
Ecuador	Guayas	Corozal	Dixon et al. 1993
Ecuador	Guayas	Manglares Churute	Arteaga et al. 2013
Ecuador	Imbabura	Lita	Torres-Carvajal et al. 2018
Ecuador	Imbabura	Paramba	Boulenger 1898
Ecuador	Imbabura	Reserva Los Cedros	iNaturalist; photo examined
Ecuador	Imbabura	Reserva Río Manduriacu	iNaturalist; photo examined
Ecuador	Loja	Orianga	Arteaga et al. 2013
Ecuador	Los Ríos	Bosque Protector Pedro Franco Dávila	Cruz & Sánchez 2016
Ecuador	Los Ríos	Río Baba	Dixon et al. 1993
Ecuador	Los Ríos	Vinces	Arteaga et al. 2013
Ecuador	Manabí	Cerro Pata de Pajaro	Arteaga et al. 2013
Ecuador	Manabí	Maicito	Dixon et al. 1993
Ecuador	Pichincha	El Chipal	iNaturalist; photo examined
Ecuador	Pichincha	El Encanto	Arteaga et al. 2013
Ecuador	Pichincha	El Paraíso	Dixon et al. 1993
Ecuador	Pichincha	Hacienda San Vicente	Arteaga et al. 2013
Ecuador	Pichincha	Maquipucuna	Arteaga et al. 2013
Ecuador	Pichincha	Mashpi Lodge	Yánez-Muñoz et al. 2009
Ecuador	Pichincha	Milpe	Arteaga et al. 2013
Ecuador	Pichincha	Mindo Garden	Arteaga et al. 2013
Ecuador	Pichincha	Mindo Lindo	Arteaga et al. 2013
Ecuador	Pichincha	Pacto	Dixon et al. 1993
Ecuador	Pichincha	Pedro Vicente Maldonado	iNaturalist; photo examined
Ecuador	Pichincha	Puerto Quito	Arteaga et al. 2013
Ecuador	Pichincha	Rainforest Monterreal	Arteaga et al. 2013
Ecuador	Pichincha	Rancho Suamox	iNaturalist; photo examined
Ecuador	Pichincha	Río Cinto	Arteaga et al. 2013
Ecuador	Pichincha	Santa Lucía Cloud Forest Reserve	Torres-Carvajal et al. 2018
Ecuador	Pichincha	Séptimo Paraíso	Arteaga et al. 2013
Ecuador	Santo Domingo de los Tsáchilas	Finca la Esperanza	Dixon et al. 1993
Ecuador	Santo Domingo de los Tsáchilas	Finca Tinalandia	Arteaga et al. 2013
Ecuador	Santo Domingo de los Tsáchilas	Santo Domingo de los Tsáchilas	Dixon et al. 1993