Mexican cantil (Agkistrodon bilineatus)

Description

Mexican cantil fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Mexican cantil description

The Mexican cantil is a venomous pitviper that is greatly feared by humans throughout its range ⁽²⁾. Like all pitvipers, the Mexican cantil has a pair of heat-sensitive pits, located between the eye and nostril on each side of the head ⁽²⁾. Its body is a dark brown ground colour, overlaid with darker brown or black bands, often fringed with white or cream scales ⁽²⁾. Juvenile cantils usually possess more distinctive banding and brightly coloured tails, used to lure prey ^{(2) (4)}.

The generic name, Agkistrodon, is derived from the Greek Ancistro,meaning ‘hook’, and odon, meaning ‘tooth’, referring to the hinged, hollow fangs of this species ⁽²⁾. The Mexican cantil has the longest fangs of any species within the Agkistrodon genus, growing to over one centimetre in length ⁽²⁾. The specific name, bilineatus, refers to the pair of striking pale stripes on each side of the head: bi-means 'two' and lineatus means 'lined' in Latin ⁽²⁾.

Also known as

cantil, Mexican moccasin.

Spanish

Cantil, Castellana.

Size

Average length: 80 cm ⁽²⁾

Maximum length: 138 cm ⁽²⁾

Mexican cantil biology

The diverse habitats occupied by the Mexican cantil throughout its range suggest it is a semi-aquatic species ⁽²⁾. Individuals have been recorded swimming in streams, marshes and even roadside ditches after nightfall, and the majority of evidence indicates that this species is primarily active at night ⁽²⁾. Adult cantils prey upon a variety of vertebrates, including amphibians, reptiles, birds and mammals ⁽²⁾, and there is a single record of a treesnake being consumed ⁽⁶⁾. Juveniles lure potential prey by ‘wiggling’ the bright yellow tail as if to mimic an invertebrate, attracting frogs and lizards ^{(2) (7)}.

The Mexican cantil gives birth to live young ⁽²⁾. Mating usually occurs between December and April, with individuals giving birth from June until August, during the rainy season ⁽²⁾. There are usually five to ten young in a litter, although extremes of three to twenty have been recorded ⁽²⁾.

Mexican cantil range

The Mexican cantil is comprised of three geographically distinct subspecies ^{(2) (3)}. The subspecies Agkistrodon bilineatus bilineatus occurs along the Pacific coast of Central America, from southern Sonora, Mexico, through Guatemala to El Salvador ⁽⁵⁾. Agkistrodon bilineatus howardgloydi is distributed throughout north-western Costa Rica and western Nicaragua, and has a limited range in El Salvador and Honduras ⁽⁵⁾. Agkistrodon bilineatus russeolusis found in northern Belize and the Yucatán Peninsula, Mexico ⁽⁵⁾.

Mexican cantil habitat

The Mexican cantil occurs in a vast range of habitats, including seasonally dry forest, tropical deciduous forest, tropical scrub forest and savanna ⁽²⁾. Habitat bordering rivers or streams is preferred, but it may also occur in grasslands and cultivated lands ⁽¹⁾.

Mexican cantil status

Classified as Near Threatened (NT) on the IUCN Red List ⁽¹⁾.

Mexican cantil threats

Despite its extensive distribution throughout Central America, the Mexican cantil is one of the most endangered snakes in the Americas ⁽²⁾. This is due to the conversion of tropical forest and thorn scrub for agricultural purposes ⁽⁵⁾, combined with human persecution throughout its fragmented range ⁽¹⁾. Populations have suffered declines of nearly 30 percent over the past 30 years and, sadly, populations continue to decrease today ⁽¹⁾.

Mexican cantil conservation

The Mexican cantil occurs in two protected areas in Mexico: the Calakmul Biosphere Reserve and the Chamela Biological Station ⁽¹⁾. The species is not currently afforded any protection from international trade by the Convention on International Trade in Endangered Species (CITES) ⁽⁸⁾.

View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more

To learn about efforts to conserve snakes around the world see:

• International Reptile Conservation Foundation:
  http://www.ircf.org
• Amphibian and Reptile Conservation:
  http://www.arc-trust.org

Authentication

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

This species information was authored as part of the ARKive and Universities Scheme.

Glossary

Generic name

The first of the two scientific names by which an animal is identified. An animal’s scientific name is the same throughout the world, although it may have different common names in different countries and languages.

Genus

A category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.

Invertebrate

An animal with no backbone. Invertebrates include insects, crustaceans, worms, molluscs and spiders.

Specific name

The second of the two scientific names by which an animal is identified.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

Vertebrates

Animals with a backbone.

References

1. IUCN Red List (November, 2009)
   http://www.iucnredlist.org
2. Campbell, J.A. and Lamar, W.W. (2004) The Venomous Reptiles of the Western Hemisphere. Cornell University Press, New York.
3. Parkinson, C.L., Zamudio, K.R. and Greene, H.W. (2000) Phylogeography of the pitviper clade Agkistrodon: historical ecology, species status, and conservation of cantils. Molecular Ecology, 9: 411-420.
4. Greene, H.W. (1992) The ecological and behavioral context for pitviper evolution. In: Campbell, J.A. and Brodie, E.D. (Eds.) Biology of the Pitvipers. Selva, Tyler, Texas.
5. Gloyd, H.K., and Conant, R. (1990) Snakes of the Agkistrodon Complex: A Monographic Review. Society for the Study of Amphibians and Reptiles, St. Louis, Missouri.
6. Bogert, C.M., and Oliver, J.A. (1945) A preliminary analysis of the herpetofauna of Sonora. Bulletin of the American Museum of Natural History, 109: 1-238.
7. Allen, E.R. (1949) Observations on the feeding habits of the juvenile cantil. Copeia, 1949(3): 225-226.
8. CITES (November, 2009)
   http://www.cites.org