Published May 6, 2024. Open access.

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Yellow Blunt-headed Snake (Imantodes inornatus)

Reptiles of Ecuador | Serpentes | Colubridae | Imantodes inornatus

English common name: Yellow Blunt-headed Snake.

Spanish common name: Cordoncillo amarilla.

Recognition: ♂♂ 103.5 cmMaximum distance from the snout to the tip of the tail. ♀♀ 95.0 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=63.2 cm..13 Imantodes inornatus can easily be identified by having a slender body, a blunt head with minute black spots, and large and bulging eyes that occupy approximately a quarter of the head’s length.1,4 This species differs from I. chocoensis by having a loreal scale and from I. cenchoa by boasting a yellowish dorsum without large blotches (Fig. 1).1,4,5 Although it may resemble snakes of the genus Leptodeira, this species differs from them by having a more compact head with more prominent eyes.

Figure showing variation among individuals of Imantodes inornatus

Figure 1: Individuals of Imantodes inornatus: Tundaloma Lodge, Esmeraldas province, Ecuador (); Canopy Tower Lodge, Panamá (); Canandé Reserve, Esmeraldas province (). j=juvenile.

Natural history: Imantodes inornatus is a nocturnal and entirely arboreal snake that inhabits well-preserved lowland and foothill rainforests, especially along streams and swamps, occurring in lower densities in forest-edge situations and plantations.4,6 During the initial storms of the rainy season, sightings of this tree snake increase.2 Yellow Blunt-headed Snakes are typically observed coiled on, or gliding through, vegetation 0.4–9 m above the ground.6,7 They are mildly venomous (harmless to humans) and capture prey using a grab-and-hold strategy aided by constriction. The diet consists of frogs, lizards (Anolis), and frog eggs (of Agalychnis and Dendropsophus).4,8,9 In the presence of a disturbance, Yellow Bluntheads tends to flee towards vegetation, emitting fetid fluids through the cloaca as a defensive mechanism. These snakes are considered docile, rarely attempting to bite.6 The clutch size in this species consists of 4 eggs.1

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Conservation: Least Concern Believed to be safe from extinction given current circumstances..10 Imantodes inornatus is listed in this category due to its wide distribution and presumed large populations that have not undergone rapid declines.10 Despite facing challenges such as deforestation and fragmentation resulting from logging, agricultural expansion, and urban development, substantial portions of undisturbed habitat are still available for this species.

Distribution: Imantodes inornatus is widely distributed throughout Mesaomerica and the Chocó biome, from the Caribbean and Pacific slopes of Honduras and Nicaragua through Panama and Costa Rica, to the Pacific lowlands of Colombia and northern Ecuador (Fig. 2).

Distribution of Imantodes inornatus in Ecuador

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

Etymology: The name Imantodes comes from the Latin word immanis (=enormous) and the Greek suffix -odes (=abundance),11 probably referring to the large size of the eyes in relation to the head. The specific epithet inornatus comes from the Latin and means “lacking decoration,” probably referring to the lack of contrasting dorsal blotches.

See it in the wild: The Yellow Blunt-headed Snake is not a common species, but there is a high probability of seeing it in well-preserved protected forests such as those of Canandé and Tesoro Escondido reserves. These snakes can be spotted by scanning understory vegetation at night, especially after a heavy rain.

Author: Amanda QuezadaaAffiliation: Khamai Foundation, Quito, Ecuador.

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

Photographer: Jose VieirabAffiliation: Tropical Herping (TH), Quito, Ecuador.,cAffiliation: ExSitu, Quito, Ecuador.

How to cite? Quezada A (2024) Yellow Blunt-headed Snake (Imantodes inornatus). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/DPPY8112

Literature cited:

  1. Myers CW (1982) Blunt-headed Vine Snakes (Imantodes) in Panama, including a new species and other revisionary notes. American Museum Novitates 2738: 1–50.
  2. Guyer C, Donnelly MA (2005) Amphibians and reptiles of La Selva, Costa Rica, and the Caribbean slope. University of California Press, Berkeley, 367 pp.
  3. Díaz-Ayala RF, Rojas-Morales JA, Zuluaga-Isaza JC, Ramírez-Castaño VA (2018) Imantodes inornatus (Boulenger, 1886) (Squamata: Dipsadidae): expansion of known range and first records from the Magdalena River valley, Colombia. Biota Colombiana 19: 219–225. DOI: 10.21068/c2018.v19n01a14
  4. 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.
  5. Torres-Carvajal O, Yánez-Muñoz MH, Quirola D, Smith E, Almendáriz A (2012) A new species of blunt-headed vine snake (Colubridae, Imantodes) from the Chocó region of Ecuador. Zookeys 244: 91–110. DOI: 10.3897/zookeys.244.3950
  6. Field notes, Reptiles of Ecuador book project.
  7. Sunyer J, Martínez Fonseca JG, Fernández MA, Ubeda Olivas MF, Obando LA (2014) Noteworthy snake records from Nicaragua (Reptilia: Serpentes). Check List 10: 1134–1147.
  8. 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.
  9. Jung J, Guo M, Crovella ME, McDaniel JG, Warkentin KM (2022) Frog embryos use multiple levels of temporal pattern in risk assessment for vibration-cued escape hatching. Animal Cognition 25: 1527–1544. DOI: 10.1007/s10071-022-01634-4
  10. Vargas Álvarez J, García Rodríguez A, Batista A, Acosta Chaves V, Bolívar W, Cisneros-Heredia DF (2016) Imantodes inornatus. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2016-1.RLTS.T176820A1448570.en.
  11. 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 Imantodes inornatus in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used.

ColombiaNariñoEstación Mar AgrícolaPinto-Erazo et al. 2020
EcuadorCarchiSendero AwáTorres-Carvajal et al. 2012
EcuadorCotopaxiFinca YakusinchiPhoto by Jane Sloan
EcuadorEsmeraldasBilsa Biological Station Ortega-Andrade et al. 2010
EcuadorEsmeraldasBosque Protector La ChiquitaTorres-Carvajal et al. 2012
EcuadorEsmeraldasBosque Protector La PerlaPhoto by Tim Christensen
EcuadorEsmeraldasCanandé ReserveThis work; Fig. 1
EcuadorEsmeraldasCube, 6 km W ofiNaturalist; photo examined
EcuadorEsmeraldasLa Concordia, 5 km W ofiNaturalist; photo examined
EcuadorEsmeraldasLa TablaMorales 2004
EcuadorEsmeraldasReserva FCATiNaturalist; photo examined
EcuadorEsmeraldasSan Lorenzo–Lita roadTorres-Carvajal et al. 2012
EcuadorEsmeraldasSan Lorenzo, 4 km E ofTorres-Carvajal et al. 2012
EcuadorEsmeraldasTundaloma LodgeMZUTI 3681; examined
EcuadorImbaburaLlurimaguaiNaturalist; photo examined
EcuadorLos RíosCentro Científico Río PalenqueMCZ R-156879; VertNet
EcuadorManabíMaicito on road to Chone Torres-Carvajal et al. 2012
EcuadorPichinchaCascada TataláiNaturalist; photo examined
EcuadorPichinchaHostería Selva VirgenPhoto by Javier Aznar
EcuadorPichinchaMaspi, 2.5 km S ofiNaturalist; photo examined
EcuadorPichinchaReserva MashpiReptiles of Ecuador book database
EcuadorPichinchaUnión Bolivarense, 4.3 km SE ofiNaturalist; photo examined
EcuadorSanto Domingo de los TsáchilasLa FloridaMHNG 2413.009; collection database
EcuadorSanto Domingo de los TsáchilasSanto Domingo de los TsáchilasMCZ R-156884; VertNet