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Neotropical Vinesnake (Oxybelis aeneus)

[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column][/vc_row][vc_row][vc_column width=”1/2″][vc_single_image image=”2109″ img_size=”large” alignment=”center” style=”vc_box_rounded”][vc_column_text]Neotropical Vinesnake, Pajarito Mtns, AZ. Photo by Jim Rorabaugh[/vc_column_text][/vc_column][vc_column width=”1/2″][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”2398″ img_size=”medium” alignment=”center” onclick=”img_link_large”][vc_column_text]Neotropical Vinesnake, Pajarito Mountains, AZ. Photo by Jim Rorabaugh[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”2399″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Neotropical Vinesnake, Pajarito Mtns, AZ. Photo by Jim Rorabaugh[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”2400″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Neotropical Vinesnake, Santa Cruz Co., AZ. Photo by Jim Rorabaugh[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”2401″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]This is why Vinesnakes are difficult to see in trees and shrubs. Northern Jaguar Reserve, Sonora. Photo by Jim Rorabaugh[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”2403″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Neotropical Vinesnake. ©2013 Dancing Snake Nature Photography[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”2402″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Neotropical Vinesnake eating an Ornate Tree Lizard. ©2013 Dancing Snake Nature Photography[/vc_column_text][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”2404″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Gray Hawk with Neotropical Vinesnake, Pena Blanca Lake, AZ. Photo by Richard Fray[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column width=”1/6″][/vc_column][vc_column width=”2/3″][vc_column_text]

Description

The Neotropical Vinesnake is unique among all serpents in the 100-Mile Circle and difficult to confuse with any other species.  It is extremely slender, the head length is three or more times the head width, the snout is pointed, and the tail is extraordinarily long: 40-41% of total length. The dorsal scales are smooth to weakly keeled and usually arranged in 17 rows at mid-body. The anal plate is divided. The dorsal color is silvery to gray or gray-brown; it may be somewhat bronze or iridescent anteriorly. Some dorsal scales have dark spots.  The venter is predominantly gray, but it is lighter and yellowish anteriorly in comparison to the dorsum.  Often there is a thin, light stripe down the center of the ventral surface onto the tail. The chin is white or yellow, and that color extends onto the body.  The record length for the species is 1700 mm total length, but Vinesnakes may on average be shorter in Arizona and northern Sonora.  Most found in Arizona are less than 1100 mm total length.

This is one of the most difficult snakes to find in the 100-Mile Circle.  Most are found on roads because they are particularly challenging to find slung through the branches of trees and shrubs where they typically remain motionless, and likely spend much of their time. This is a diurnal species, and those found on roads are often found early to mid-morning. When spotted in shrubs or trees, they are usually two meters or less off the ground.  However, they sleep in loose coils two to five meters off the ground amidst branches and foliage. They have been observed from March into November in our area, although most are found during the summer rainy season.  The vast majority of records are for the Pajarito-Atascosa Mountain range complex, from about Walker Canyon east to Arivaca Lake and Ruby. A specimen was collected in 1968 from “near Washington Camp” in the Patagonia Mountains, there are at least four unconfirmed (no photos or specimens) reports from the western flank of the Santa Rita Mountains (Montosa Canyon and Agua Caliente Cave), and a similarly unconfirmed report from Thomas Canyon on the eastern slope of the Baboquivari Mountains. It was also collected in 1925 from the outskirts of Tucson, and some suggest that historical riparian woodlands along the Santa Cruz River may have provided habitat for this species. The only records on the Sonora side of the Circle are from the southern extension of Pajarito-Atascosa Mountains southwest of Nogales, and an imprecise locality that is probably along Highway 2 in the mountains west of Cananea. In our area, these snakes are found in mesquite-invaded semi-desert grasslands, oak savanna and woodland, and marginally into pine-oak woodland at elevations of 1160-1650 m. They are sometimes found in riparian canyons, but are by no means restricted to them. This tropical species, which is at the very northern edge of its range in southern Arizona, is distributed southward through Latin America to Bolivia and Brazil.

Clutches of two to nine (mean = 4) eggs are deposited under surface litter probably during summer. Hatchlings resemble small adults and are about 290 to 374 mm SVL. Small lizards, such as Ornate Tree Lizards and whiptails, are common prey.  Frogs, fish, small birds, rodents, and insects have also been reported in the diet. Enlarged, grooved teeth in the rear of the upper jaw help deliver venom from a Duvernoy’s gland to prey items. Venom is chewed into the wound. If threatened, the Neotropical Vinesnake often opens its black-lined mouth and may strike and bite. If allowed to chew, swelling, blistering, discoloration, itchiness, and/or numbness may occur at the site of the bite.

With a valid hunting license, four Neotropical Vinesnakes can be collected per year or possessed alive or dead. The conservation status of this species has not yet been evaluated by the IUCN.

Suggested Reading:

Brennan, T.C., and A.T. Holycross. 2006. Amphibians and Reptiles in Arizona. Arizona Game and Fish Department, Phoenix, AZ.

Ernst, C.H., and E.M. Ernst. 2003. Snakes of the United States and Canada. Smithsonian Books, Washington, D.C.

Goldberg, S.R. 1998. Reproduction in the Mexican vine snake Oxybelis aeneus (Serpentes: Colubridae). Texas J. Science 50:51–56.

Groschupf, K., and S. Lower. 1988. Oxybelis aeneus (Brown Vine Snake). Behavior. Herpetological Review 19(4):85.

Keiser, E.D. Jr. 1982. Oxybelis aeneus (Wagler). Catalogue of American Amphibians and Reptiles 305:1–4.

Van Devender, T.R., C.H. Lowe, and H.E. Lawlor. 1994. Factors influencing the distribution of the Neotropical Vine Snake (Oxybelis aeneus) in Arizona and Sonora, Mexico. Herpetological Natural History 2(1):25-42.

Author: Jim Rorabaugh

For additional information on this species, please see the following volume and pages in the Sonoran Herpetologist: 2009 Aug:86-87.

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