Crotalus oreganus abyssus

Crotalus oreganus abyssus
Grand Canyon rattlesnake Havasu Canyon, Arizona
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Viperidae
Genus:	Crotalus
Species:	C. oreganus
Subspecies:	C. o. abyssus
Trinomial name
Crotalus oreganus abyssus Klauber, 1930
Synonyms
Crotalus confluentus abyssus Klauber, 1930 Crotalus viridis abyssus – Klauber, 1936[1] Crotalus oreganus abyssus – Ashton & de Queiroz, 2001[2]

Common names: Grand Canyon rattlesnake,^[3] canyon bleached rattlesnake.^[4]

Crotalus oreganus abyssus is a venomous pit viper subspecies^[3] found only in the U.S. states of Arizona and Utah.

Description

This is a medium to large rattlesnake. Adults measure 16–54 inches (41–137 cm) in total length.

Dorsally, they have dark blotches on a variety of base colors ranging from reddish, pink, yellow/green, light tan, to gray. The blotches usually become crossbands near the tail. The young usually have more prominent blotches and facial markings than the adults. Some adults have no body markings.

The rostral scale usually comes into contact with more than 2 internasal scales.

Geographic range

Found in northwestern and north-central Arizona along both rims and the floor of the Grand Canyon and adjacent areas,, and North into Utah on the Kaiparowits Plateau between the Escalante River and Paria River Drainages of Kane and Garfield Counties, Utah.^[5][6][7][8]

Habitat

The snake is found in a variety of habitats, including grassland, Great Basin Desert scrubland, bottoms in the Grand Canyon, talus and cliff slopes, rolling hills and bajadas in pinion-juniper woodland, and pine forests.

Behavior

It is primarily diurnal but can be active around the clock when conditions are favorable. The cryptic coloration and calm demeanor of this subspecies often allows it to escape detection from passers-by.

Feeding

It feeds on mice, lizards, and birds. Like other pit vipers, the Grand Canyon Rattlesnake has heat-sensitive pits that identify body heat of animals to help with hunting.^[9] Rock squirrels, which are common in the Grand Canyon area, evade the snake through a process called "mobbing," where the squirrel will attack the snake by kicking dirt and rocks and rapidly waving their tails to heat the air around them, causing the snake to believe there is a larger mammal coming to attack.^[10]

Taxonomy notes

Some researchers list this taxon as elevated to a full species as (Crotalus abyssus),^[5] or as a subspecies of the Great Basin Rattlesnake (Crotalus lutosus) as Crotalus lutosus abyssus, in the Annotated Checklist of the Rattlesnakes (Second Edition), published in The Biology of Rattlesnakes II 2017.^[11]

References

1. McDiarmid RW; Campbell JA; Touré T. (1999). Snake Species of the World: A Taxonomic and Geographic Reference. Vol. 1. Herpetologists' League. ISBN 1-893777-01-4.
2. Ashton KG; de Queiroz A. (2001). "Molecular systematics of the western rattlesnake, Crotalus viridis (Viperidae), with comments on the utility of the d-loop in phylogenetic studies of snakes" (PDF). Molecular Phylogenetics and Evolution. 21 (2): 176–189. Archived from the original (PDF) on 2007-09-29.
3. "Crotalus oreganus abyssus". Integrated Taxonomic Information System. Retrieved 28 November 2006.
4. Wright AH; Wright AA. (1957). Handbook of Snakes (7th printing, 1985 ed.). Comstock Publishing Associates. ISBN 0-8014-0463-0.
5. Gordon W. Schuett; Martin J. Feldner; Charles F. Smith; Randall S. Reiserer (2016). Rattlesnakes of Arizona. Vol. 1. ISBN 978-1938850189.
6. Gordon W. Schuett; Charles F. Smith; Bob Ashley (2018). Rattlesnakes of the Grand Canyon. ISBN 978-1938850585.
7. Jonathan A. Campbell; William W. Lamar (2004). The Venomous Reptiles of the Western Hemisphere, Vols.1 & 2. ISBN 978-0801441417.
8. Brian Hubbs; Brendan O'Connor (2012). A Guide to the Rattlesnakes and other Venomous Serpents of the US. ISBN 978-0975464137.
9. "Rattlesnakes". Grand Canyon National Park Arizona. National Park Service.
10. Donald Owings; Richard Coss; Diane McKernon; Matthew Rowe; Patricia Arrowood. "Snake-directed antipredator behavior of rock squirrels (Spermophilus variegatus):Population differences and snake-species discrimination". Behaviour. 138 (5): 575–595. doi:10.1163/156853901316924485.
11. Kent R. Beaman; William K. Hayes (2017). The Biology of Rattlesnakes. Vol. II. ISBN 978-1938850547.

Further reading

• Klauber, L.M. (1930). "New and Renamed Subspecies of Crotalus confluentus Say, with Remarks on Related Species". Trans. San Diego Soc. Nat. Hist. 6 (3): 114–117 + Plate 11, figure 1.

External links

• Crotalus oreganus at the Reptarium.cz Reptile Database. Accessed 12 December 2007.
• Images of Crotalus oreganus abyssus at California Reptiles and Amphibians. Accessed 18 June 2008.