Published September 25, 2021. Updated November 20, 2023. Open access.

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White Worm-Lizard (Amphisbaena alba)

Reptiles of Ecuador | Amphisbaenia | Amphisbaena alba

English common names: White Worm-Lizard, White-bellied Worm-Lizard, Red Worm-Lizard, Giant Worm-Lizard.

Spanish common names: Pudridora blanca, culebra ciega, culebra de dos cabezas, morrona, lagarto gusano, tatacoa.

Recognition: ♂♂ 78 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=71.8 cm. ♀♀ 81 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=74.6 cm..1 The White Worm-Lizard (Amphisbaena alba) is a unique reptile, neither lizard nor snake, it belongs to the suborder Amphisbaenia.2,3 It is one of the largest worm lizards in the world. At first glance, it can be mistaken for a snake or a caecilian, but it can be easily distinguished by its unique pale yellowish or cream coloration and scales arranged in rings around the body.2,4 The eyes in this species are small, vestigial, but functional; hence the local name culebra ciega (meaning “blind snake”). In Ecuador, A. alba can be differentiated from the co-occurring A. bassleri by the absence of both black spots on the body and an autotomy ring in the tail (a segment where the tail can be detached).2 Neonates of A. alba may have some black spots on the body but they do not have an autotomy ring on the tail.2,5 From the snake-like lizard Bachia trisanale, A. alba differs by its larger size and by the absence of limbs.6 Sexual dimorphism is not known in A. alba.1

Figure showing an adult male of Amphisbaena alba

Figure 1: Adult male of Amphisbaena alba from Santa Rosalía, Vichada department, Colombia.

Natural history: Amphisbaena alba is an extremely rareTotal average number of reported observations per locality less than three. rare species in the western Amazon, but is slightly more frequently encountered in Colombia and Venezuela. There are only four records of this species in Ecuador. Amphisbaena alba is a fossorial and primarily nocturnal7 reptile that inhabits rainforests, savannas, xeric shrublands,8,9 grasslands, farms, and urban and peri-urban areas.79 White Worm-Lizards spend most of their time buried in a fixed tunnel system,1012 as well as in forest debris,12,13 nests of leafcutter ants (Atta cephalotes1416 and Acromyrmex sp.17) and termites,16,18 and under decaying logs.11 Individuals can be found outside their burrows during or after heavy rains.7,13,16,18 White Worm-Lizards can be found buried up to 1 m deep, where the amount of oxygen is 50% less than that at the surface level.19 This species has low ventilation requirements; its oxygen absorption rate is lower than that of most lizards and snakes,20 and has an extraordinary high O2 affinity compared to other poikilotherm vertebrates, which means its tissues can become oxygenated under lower oxygen pressures.12,21

Amphisbaena alba has an extremely muscular body with which it digs its own tunnels. This reptile has a rectilinear form of locomotion that resembles the way a worm moves. The muscles in this species have a greater amount of myoglobin (myoglobin traps oxygen inside the muscle cells so that they produce enough energy for muscle contraction) than any other reptile.12,22 It is a thigmothermic species, meaning individuals thermoregulate their body temperature mainly by direct contact with the ground.8

White Worm-Lizards have 4–10 pre-cloacal glands that produce a secretion that leaves a trail on the substrate.2325 In this way, individuals can orient themselves along fixed paths and tunnels.23 Through smell, the worm lizards also have the ability to follow the chemical trail left by leafcutter ants.26,27 When an Amphisbaena alba finds an active ant trail, it follows it until it reaches the nest, where it buries itself.16 Inside the nest, the reptile may never visit the delicate fungus crops that are vital for the survival of the ants, as this could elicit a defense reaction by the ants, which are known to harm A. alba.16 Instead, the worm lizard frequents the chambers used as “garbage dumps” within the nests.16 For A. alba, the ant nests are a hiding place as well as a hunting ground, since these are inhabited by insects they use as food, such as adults and larvae of the Coleosis biloba beetle,28 spiders, and cockroaches.16

The presence of Amphisbaena alba in leafcutter ant nests is supported by the fact the parasite Raillietiella gigliolii is found in the lungs of the amphisbaenian.29,30 This parasite uses an insect as an intermediate host, but ants are too small to ingest R. gigliolii eggs.29 For the egg’s development, they need to be ingested by a larger host.29 In the nests of the ant Atta cephalotes, the faeces of A. alba are quickly cut and transferred to the chambers used as a garbage dump, where they are presumably ingested by the larva of the beetle C. biloba.16,29 Amphisbaena alba is also host to other parasites, including protozoans (genera Choleoeimeria and Isospora)31 and nematodes (Maracaya belemensis, Aplectana albae, A. minaensis, Tachygonetria vivipara, and certain species in the genera Alaeuris and Gyrinicola).3234

Amphisbaena alba is known as mãe de saúva (=mother of leafcutting ants) in Brazil, which reflects its association with ant nests.”

Claudia Azevedo-Ramos, 1994.35

White Worm-Lizards are mainly carnivorous and insectivorous.1 Although plants have been found in their stomachs, it is assumed that they have been consumed by accident.1 Invertebrate prey items include adult beetles and their larvae (Coleosis biloba, Smilax spilosa, species in the family Passalidae, and members of the genera Physea, Reninus, Ateuchus, Eustales, and Ateianus),16,36 ants (Atta cephalotes, Labidus coecus, Eciton mexicanum, and species in the genus Nomamyrmex),16,37 cockroaches (Pycnoscelus surinamensis), termites (Neocapritermes sp.),16 hemipterans,1 mole crickets, grashoppers, spiders,1 scorpions,1 pseudoscorpions,1 and annelids.1 Vertebrate prey items include lizards (genus Tropidurus) and their eggs,1 snakes (Anilius scytale15 and an unidentified Liotyphlops1), and rodents.7 In captivity, individuals can feed on meat, beetle larvae (Tenebrionidae),38 snakes,39 and baby mice.1

As a defense mechanism, individuals of Amphisbaena alba tend to flee or bury themselves in the ground.40 They can swim more than 2.5 km in open water as a measure to escape from predators.41 Since the head and tail of A. alba look similar shape and coloration, predators may attack the tail, believing is the head, and thus fail to inflict vital damage to the worm lizard.40 If the threat persists, the reptile reacts by opening the mouth, raising the tail, and adopting a horseshoe shape that it can make and undo in a fast and frantic way.7,36,42 White Worm-Lizards are capable of biting and twisting to detach parts of the predator.2,7 There is a record of an A. alba that mutilated the leg of a Southern Lapwing (Vanellus chilensis) while it was being attacked by it.7 Predators of A. alba include chickens,42 hawks (Rupornis magnirostris),43 and snakes (Drymarchon corais44 and Bothrops asper45). In Venezuela, locals in some places hunt White Worm-Lizards to concoct remedies,7,38 but these remedies are unlikely to have any positive effect on any disease.

Amphisbaena alba is a species that reproduces seasonally during the dry season.1,7 The smallest reproductively active female recorded measured 45.7 cm in SVL and the smallest reproductively active male measured 42.2 cm SVL.1 Clutch size ranges from 6 to 16 eggs.1,46 The eggs measure 3.1–3.9 cm in length46,47 and are placed inside the nests of leafcutter ants.35,48

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Conservation: Least Concern Believed to be safe from extinction given current circumstances..9 Amphisbaena alba in listed this category because it is widely distributed and its population status has been stable during the last 10 years.9 However, the species could suffer local population declines due to habitat destruction and the excessive use of pesticides that decimate insect populations, such as leafcutter ants, which are crucial to the survival of A. alba.16 Vehicular traffic is another source of mortality for individuals of this species. Given their terrestrial habits and their low ability to move on the ground, these animals cannot easily dodge cars and are frequently run over.49 Also, A.alba suffers persecution at the hands of settlers, who either kill this worm lizard believing it is a venomous animal, or use it as a traditional remedy.7,38

Distribution: Amphisbaena alba is widely distributed throughout the Neotropical lowlands of northern South America. The species has been recorded in Bolivia, Brazil, Colombia, Ecuador (Fig. 2), French Guiana, Guyana, Paraguay, Peru, Suriname, Trinidad, and Venezuela.

Distribution of Amphisbaena alba in Ecuador

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

Etymology: The name Amphisbaena is a Latin word used to refer to a “fabulous serpent having a head at each end.”50 In this species, the head and the tail are very similar, which can give the illusion that the animal is advancing backwards. The specific epithet alba, which comes from the Latin word albus (meaning “white”),50 refers to the light coloration of this species.4

See it in the wild: The White Worm-Lizard is extremely difficult to see in Ecuador. There are only four records of this reptile in the country. In other parts of the species’ range, individuals are most often found on the ground after heavy rains or inside the mounds of the leafcutter ants.

Acknowledgments: Special thanks to Alejandro Bonaiuto for providing natural history data on this species and to Duvan Zambrano for providing the photograph used to illustrate the species in this account.

Special thanks to Kelly Geer for symbolically adopting the White Worm-Lizard and helping bring the Reptiles of Ecuador book project to life.

Click here to adopt a species.

Author: Jose VieiraaAffiliation: Tropical Herping (TH), Quito, Ecuador.,bAffiliation: ExSitu, Quito, Ecuador.

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

Photographer: Duvan ZambranocAffiliation: Universidad del Tolima, Ibagué, Colombia.

How to cite? Vieira J (2023) White Worm-Lizard (Amphisbaena alba). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/SJXO6764

Literature cited:

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  17. Peregrine DJ (1975) Some field observations on the bachacs of Trinidad. Journal of the Trinidad Field Naturalists’ Club 1975: 46–54.
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  19. Rawitscher FK (1944) Problemas de fitoecologia com considerações especiais sobre o Brasil meridional. Boletim da Faculdade de Filosofia, Ciências e Letras, Universidade de São Paulo Botânica 3: 1–111. DOI: 10.11606/issn.2318-5988.v3i0p7-111
  20. Abe AS, Johansen K (1987) Gas exchange and ventilatory responses to hypoxia and hypercapnia in Amphisbaena alba (Reptilia: Amphisbaenia). Journal of Experimental Biology 127: 159–172.
  21. Standaert T, Johansen K (1974) Cutaneous gas exchange in snakes. Journal of Comparative Physiology 89: 313–320. DOI: 10.1007/BF00695349
  22. Weber RE, Johansen K, Abe AS (1980) Myoglobin from a burrowing reptile, Amphisbaena alba. Comparative Biochemistry & Physiology 68: 159–165. DOI: 10.1016/0300-9629(81)90336-4
  23. Jared C, Antoniazzi MM, Silva JRMC, Freymller E (1999) Epidermal glands in Squamata: microscopical examination of precloacal glands in Amphisbaena alba (Amphisbaenia, Amphisbaenidae). Journal of Morphology 241: 197–206.
  24. Antoniazzi MM, Jared C, Pellegrini CMR, Macha N (1993) Epidermal glands in Squamata: morphology and histochemistry of the pre-cloacal glands in Amphisbaena alba (Amphisbaenia). Zoomorphology 113: 199–203. DOI: 10.1007/BF00394860
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  29. Winch JM, Riley J (2009) Experimental studies on the life-cycle of Raillietiella gigliolii (Pentastomida: Cephalobaenida) in the South American worm-lizard Amphisbaena alba: a unique interaction involving two insects. Parasitology 91: 471–481. DOI: 10.1017/S0031182000062715
  30. Ali JH, Riley J, Self JT (1984) A revision of the taxonomy of pentastomid parasites (genus Raillietiella Sambon, 1910) from American snakes and amphisbaenians. Systematic Parasitology 6: 87–97. DOI: 10.1007/BF02185516
  31. Lainson R (2003) Some coccidial parasites of the lizard Amphisbaena alba (Reptilia: Amphisbaenia: Amphisbaenidae). Memórias do Instituto Oswaldo Cruz 98: 927–936. DOI: 10.1590/s0074-02762003000700012
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  38. Alejandro Bonaiuto, pers. comm.
  39. Duellman WE (2005) Cusco amazónico: the lives of amphibians and reptiles in an Amazonian rainforest. Cornell University Press, Ithaca, 433 pp.
  40. Field notes of Jose Vieira.
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  43. Santos WM, Rosado FR (2009) Dados preliminares da biologia do Gavião-Carijó (Rupornis magnirostris, Gmelin, 1788) na região noroeste do Paraná. Revista em Agronegócio e Meio Ambiente 2: 421–430. DOI: 10.17765/2176-9168.2009v2n3p421-430
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  47. De Barros-Filho JD, Barreto Nascimento L, Barun A, Perry G (2003) Amphisbaena alba (White-bellied Worm Lizard). Reproduction. Herpetologcal Review 34: 243.
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Appendix 1: Locality data used to create the distribution map of Amphisbaena alba in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used.

EcuadorOrellanaAucaOrcés & Matheus (1988)
EcuadorOrellanaTivacunoOrcés & Matheus (1988)
PeruLoretoZona Reservada GüeppíYánez-Muñóz & Vanegas 2008