Published March 26, 2024. Open access.

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Olive Forest-Racer (Dendrophidion dendrophis)

Reptiles of Ecuador | Serpentes | Colubridae | Dendrophidion dendrophis

English common names: Olive Forest-Racer, Tawny Forest Racer.

Spanish common name: Corredora selvática olivácea.

Recognition: ♂♂ 114.2 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=66.8 cm. ♀♀ 118.3 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=69.3 cm..15 Dendrophidion dendrophis can be identified from all other snakes in the Ecuadorian Amazon by presenting a combination of keeled dorsal scales arranged in 17 rows at mid-body, dark crossbands with embedded pale ocelli (Fig. 1), and conspicuously large eyes.13 The interstitial skin is yellow, evident when the snake inflates the neck.4 This species differs from Drymobius rhombifer by presenting straight, transverse bars instead of ovoid blotches.2 From the juveniles of Chironius fuscus, it differs in having keeled dorsal scales.13

Figure showing variation among individuals of Dendrophidion dendrophis

Figure 1: Individuals of Dendrophidion dendrophis: Jatun Sacha Biological Reserve, Napo province, Ecuador (); Leticia, Amazonas state, Colombia (). j=juvenile.

Natural history: Dendrophidion dendrophis is a terrestrial snake that inhabits old-growth to heavily disturbed rainforests. The species also tolerates forest-edge situations, but seems to be absent from pastures and other entirely deforested habitats.4 Olive Forest-Racers are diurnal and more likely to be active during sunny days. The majority of their activity occurs at ground level but individuals may occasionally be spotted on low vegetation.4,6 They can also be seen crossing roads and trails or swimming across bodies of water, including major Amazonian rivers.4,6 At night, they roost on low (within 2 m from the ground) understory vegetation.25 These snakes are specialized on feeding on frogs,5 which are located visually through a combination of sit-and-wait and active chasing strategies.1,4 The Forest-Racer, when cornered, subtly inflates its neck, opens the mouth aggressively, and strikes.6 Its tail is long, fragile, and breaks off easily when grabbed by a predator, enabling the escape and survival of the snake.5,7 The clutch size in this species consists of 4–6 eggs.2,4,5 Breeding is presumed to occur year-round.5

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Conservation: Least Concern Believed to be safe from extinction given current circumstances..8 Dendrophidion dendrophis is listed in this category primarily because the species is widely distributed, occurs in protected areas, and is able to tolerate some degree of habitat disturbance so long as forest remain. Although little is known about threats to this species, deforestation and the decline in the number of anuran prey due to pollution and emerging diseases could have a negative localized impact on some populations.

Distribution: Dendrophidion dendrophis is widespread throughout the Amazon rainforest Brazil, Peru, Ecuador (Fig. 2), Colombia, Suriname, Guyana, French Guyana and Venezuela.

Distribution of Dendrophidion dendrophis in Ecuador

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

Etymology: The genus name Dendrophidion comes from the Greek words dendron (=tree) and ophidion (=snake).9 The specific epithet dendrophis has the same etymological origin as the genus name.

See it in the wild: Prime locations for the Olive Forest-Racer include Yasuní Scientific Station and Jatun Sacha Biological Reserve, where the snakes are most easily spotted sleeping on low vegetation along forest trails at night.

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

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

How to cite? Arteaga A (2024) Olive Forest-Racer (Dendrophidion dendrophis). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/BKUM8702

Literature cited:

  1. Lieb CS (1988) Systematic status of the Neotropical snakes Dendrophidion dendrophis and D. nuchalis. Herpetologica 44: 162–175.
  2. Duellman WE (1978) The biology of an equatorial herpetofauna in Amazonian Ecuador. Publications of the Museum of Natural History, University of Kansas 65: 1–352.
  3. Dixon JR, Soini P (1986) The reptiles of the upper Amazon Basin, Iquitos region, Peru. Milwaukee Public Museum, Milwaukee, 154 pp.
  4. Martins M, Oliveira ME (1998) Natural history of snakes in forests of the Manaus region, Central Amazonia, Brazil. Herpetological Natural History 6: 78–150.
  5. Da Costa Prudente AL, Maschio GF, Yamashina CE, Santos-Costa MC (2007) Morphology, reproductive biology and diet of Dendrophidion dendrophis (Schlegel, 1837) (Serpentes, Colubridae) in Brazilian Amazon. South American Journal of Herpetology 2: 53–58.
  6. Field notes, Reptiles of Ecuador book project.
  7. Natera-Mumaw M (2008) Nuevos registros geográficos y notas bioecológicas de Dendrophidion dendrophis (Schlegel, 1837) y Dendrophidion nuchale (Peters, 1863) (Serpentes: Colubridae) en Venezuela, con comentarios sobre la taxonomía de Dendrophidion nuchale. Herpetotropicos 4: 11–16.
  8. Ines Hladki A, Ramírez Pinilla M, Renjifo J, Urbina N, Nogueira C, Gagliardi G, Cisneros-Heredia DF, Hoogmoed M, Schargel W, Rivas G (2019) Dendrophidion dendrophis. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2019-3.RLTS.T203286A2762992.en
  9. 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 Dendrophidion dendrophis in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used.

ColombiaCaquetáFlorencia Cárdenas Hincapié & Lozano Bernal 2023
ColombiaPutumayoReserva La Isla EscondidaiNaturalist; photo examined
ColombiaPutumayoVereda PalestinaiNaturalist; photo examined
EcuadorMorona SantiagoChiguazaUSNM 237045; VertNet
EcuadorMorona SantiagoCusuimeOrtega-Andrade 2010
EcuadorMorona SantiagoLogroño, 1.4 km N ofNogueira et al. 2019
EcuadorMorona SantiagoMacasLieb 1988
EcuadorMorona SantiagoMacumaiNaturalist; photo examined
EcuadorMorona SantiagoSan José de MoronaLieb 1988
EcuadorNapoIkiam, environs ofiNaturalist; photo examined
EcuadorNapoItimandi, 5 km E ofiNaturalist; photo examined
EcuadorNapoJatun Sacha Biological StationThis work; Fig. 1
EcuadorNapoPitalala, sendero cañonesReptiles of Ecuador book database
EcuadorNapoRío SunoUSNM 237047; VertNet
EcuadorNapoSuchipakari LodgeReptiles of Ecuador book database
EcuadorNapoYachana ReserveBeirne et al. 2013
EcuadorOrellanaConcepciónUSNM 237048; VertNet
EcuadorOrellanaEl CocaMHNG 2397.06; collection database
EcuadorOrellanaPozo Pindo 11Cadena & Brito 2017
EcuadorOrellanaReserva Río BigalGarcía et al. 2021
EcuadorOrellanaRío PucunoUSNM 237049; VertNet
EcuadorOrellanaTambocochaNogueira et al. 2019
EcuadorOrellanaTiputini Biodiversity Station iNaturalist; photo examined
EcuadorOrellanaVía Maxus, km 49Nogueira et al. 2019
EcuadorOrellanaYasuní Scientific StationiNaturalist; photo examined
EcuadorPastazaArutamNogueira et al. 2019
EcuadorPastazaCabeceras del BobonazaUSNM 237054; VertNet
EcuadorPastazaCentro Ecológico Zanja ArajunoNogueira et al. 2019
EcuadorPastazaChichirotaUSNM 237052; VertNet
EcuadorPastazaComunidad TarangaroNogueira et al. 2019
EcuadorPastazaJuyuintzaNogueira et al. 2019
EcuadorPastazaMontalvoNogueira et al. 2019
EcuadorPastazaPozo Garza 1Nogueira et al. 2019
EcuadorPastazaRío AlpayacuLieb 1988
EcuadorPastazaRío Arajuno, headwaters ofUSNM 237055; VertNet
EcuadorPastazaRío CorrientesUSNM 237053; VertNet
EcuadorPastazaRío HuiyayacuUSNM 237056; VertNet
EcuadorPastazaRío PastazaLieb 1988
EcuadorPastazaSanta AnaNogueira et al. 2019
EcuadorPastazaSumak Kawsay In SituiNaturalist; photo examined
EcuadorSucumbíosBrisas del Cuyabeno, 1.6 km N ofNogueira et al. 2019
EcuadorSucumbíosLa Selva LodgeNogueira et al. 2019
EcuadorSucumbíosLimoncocha Biological ReserveLieb 1988
EcuadorSucumbíosPitsorie-SetsaccoNogueira et al. 2019
EcuadorSucumbíosRío AguaricoUSNM 237051; VertNet
EcuadorSucumbíosSan Pablo de KantesiyaMHNG 2309.061; collection database
EcuadorSucumbíosSanta Cecilia Duellman 1978
EcuadorSucumbíosTerritorio Cofán DurenoYánez-Muñoz & Chimbo 2007
EcuadorZamora ChinchipeBombuscaroPhoto by Darwin Núñez
EcuadorZamora ChinchipeReserva MaycuReptiles of Ecuador book database
EcuadorZamora ChinchipeSubcuenca del Río TundaymeBetancourt et al. 2018
PeruAmazonasPuerto GalileaLieb 1988
PeruAmazonasRío CenepaLieb 1988
PeruLoretoCampo AndoasValqui Schult 2015
PeruLoretoMishanaLieb 1988
PeruLoretoMoroponMPM H 8919; VertNet