Published March 8, 2024. Open access.

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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 (Panama).

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..13 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.13 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.13 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.14

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.24 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.14 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).

Distribution of Chironius grandisquamis in Ecuador

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-MesaaAffiliation: Escuela de Ciencias Aplicadas e Ingeniería, Universidad EAFIT, Medellín, Colombia. and Esteban Garzón-FrancobAffiliation: Colecciones Biológicas de la Universidad CES (CBUCES), Facultad de Ciencias y Biotecnología, Universidad CES, Medellín, Colombia.

Editor: Alejandro ArteagacAffiliation: Khamai Foundation, Quito, Ecuador.

Photographer: Jose VieiradAffiliation: 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: DOI: 10.47051/CQWI9720

Literature cited:

  1. 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.
  2. 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.
  3. Arteaga A, Bustamante L, Guayasamin JM (2013) The amphibians and reptiles of Mindo. Universidad Tecnológica Indoamérica, Quito, 257 pp.
  4. MECN (2010) Serie herpetofauna del Ecuador: El Chocó esmeraldeño. Museo Ecuatoriano de Ciencias Naturales, Quito, 232 pp.
  5. 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
  6. 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.
  7. Esteban Garzón-Franco, field observation.
  8. Field notes, Reptiles of Ecuador book project.
  9. 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.
  10. Wilson LD, Lamar W, Cisneros-Heredia DF, Arredondo JC, Daza J (2015) Chironius grandisquamis. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2015-4.RLTS.T203281A2762910.en
  11. Merrem B (1790) Beitrage zur Naturgeschichte. Duisburg um Lemgo, Berlin, 141 pp.
  12. 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.

ColombiaCauca"López"iNaturalist; photo examined
ColombiaNariñoReserva Natural El PangániNaturalist; photo examined
ColombiaNariñoRicaurteAMNH 108309; VertNet
EcuadorAzuayUzhcurumiArteaga et al. 2013
EcuadorCañarHidroeléctrica OcañaArteaga et al. 2013
EcuadorCañarHuatacón (lower part)Arteaga et al. 2013
EcuadorCarchiChical, 3 km SW ofArteaga et al. 2013
EcuadorCarchiTobar DonosoSamec & Samec 1988
EcuadorCarchiVía LitaArteaga et al. 2013
EcuadorCotopaxiBosque Privado JDLSPellet 2017
EcuadorCotopaxiLas PampasArteaga et al. 2013
EcuadorEl OroCerro AzulArteaga et al. 2013
EcuadorEl OroPiñasArteaga et al. 2013
EcuadorEl OroReserva Biológica BuenaventuraArteaga et al. 2013
EcuadorEl OroZaracayiNaturalist; photo examined
EcuadorEsmeraldasAlrededores de CaimitoTorres-Carvajal et al. 2018
EcuadorEsmeraldasBilsa Biological ReserveOrtega-Andrade et al. 2010
EcuadorEsmeraldasCerro CeiboArteaga et al. 2013
EcuadorEsmeraldasDurangoTorres-Carvajal et al. 2018
EcuadorEsmeraldasJesús del Gran PoderiNaturalist; photo examined
EcuadorEsmeraldasMuisne–PedernalesArteaga et al. 2013
EcuadorEsmeraldasPlaya de OroDixon et al. 1993
EcuadorEsmeraldasPlayón de San FranciscoTorres-Carvajal et al. 2018
EcuadorEsmeraldasReserva Tesoro EscondidoiNaturalist; photo examined
EcuadorEsmeraldasRío SantiagoArteaga et al. 2013
EcuadorEsmeraldasRío SapayoDixon et al. 1993
EcuadorEsmeraldasTundaloma LodgeTorres-Carvajal et al. 2018
EcuadorGuayasCerro de HayasCruz-García et al. 2020
EcuadorGuayasCerro El MangoArteaga et al. 2013
EcuadorGuayasCorozalDixon et al. 1993
EcuadorGuayasManglares ChuruteArteaga et al. 2013
EcuadorImbaburaLitaTorres-Carvajal et al. 2018
EcuadorImbaburaParambaBoulenger 1898
EcuadorImbaburaReserva Los CedrosiNaturalist; photo examined
EcuadorImbaburaReserva Río ManduriacuiNaturalist; photo examined
EcuadorLojaOriangaArteaga et al. 2013
EcuadorLos RíosBosque Protector Pedro Franco DávilaCruz & Sánchez 2016
EcuadorLos RíosRío BabaDixon et al. 1993
EcuadorLos RíosVincesArteaga et al. 2013
EcuadorManabíCerro Pata de PajaroArteaga et al. 2013
EcuadorManabíMaicitoDixon et al. 1993
EcuadorPichinchaEl ChipaliNaturalist; photo examined
EcuadorPichinchaEl EncantoArteaga et al. 2013
EcuadorPichinchaEl ParaísoDixon et al. 1993
EcuadorPichinchaHacienda San VicenteArteaga et al. 2013
EcuadorPichinchaMaquipucunaArteaga et al. 2013
EcuadorPichinchaMashpi LodgeYánez-Muñoz et al. 2009
EcuadorPichinchaMilpeArteaga et al. 2013
EcuadorPichinchaMindo GardenArteaga et al. 2013
EcuadorPichinchaMindo LindoArteaga et al. 2013
EcuadorPichinchaPactoDixon et al. 1993
EcuadorPichinchaPedro Vicente MaldonadoiNaturalist; photo examined
EcuadorPichinchaPuerto QuitoArteaga et al. 2013
EcuadorPichinchaRainforest MonterrealArteaga et al. 2013
EcuadorPichinchaRancho SuamoxiNaturalist; photo examined
EcuadorPichinchaRío CintoArteaga et al. 2013
EcuadorPichinchaSanta Lucía Cloud Forest ReserveTorres-Carvajal et al. 2018
EcuadorPichinchaSéptimo ParaísoArteaga et al. 2013
EcuadorSanto Domingo de los TsáchilasFinca la EsperanzaDixon et al. 1993
EcuadorSanto Domingo de los TsáchilasFinca TinalandiaArteaga et al. 2013
EcuadorSanto Domingo de los TsáchilasSanto Domingo de los TsáchilasDixon et al. 1993