Tiger Rattlesnake – Tucson Herpetological Society

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Tiger Rattlesnake (Crotalus tigris)

[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column][/vc_row][vc_row][vc_column width=”1/2″][vc_single_image image=”841″ img_size=”large” alignment=”center” style=”vc_box_rounded”][vc_column_text]Tiger Rattlesnake, North Mtn Park, Phoenix, 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=”2754″ img_size=”medium” alignment=”center” onclick=”img_link_large”][vc_column_text]Tiger Rattlesnakes. Photo by R Johnson[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”2755″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Tiger Rattlesnake. ©2013 Dancing Snake Nature Photography[/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=”2756″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Mother Tiger Rattlesnake from the Suizo Mtns, Pinal Co., with five neonates, born 2 July 2014. Image taken on 9 July, 2014. Note the shed skin at top center of image, indicating ecdysis has occurred with one of the young. Image by Roger A. Repp.[/vc_column_text][gap size=”12px” id=”” class=”” style=””][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”2758″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Tiger Rattlesnake, Photo by Young Cage.[/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=”2759″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Tiger Rattlesnake, Photo by Young Cage.[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”2760″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Tiger Rattlesnake, Photo by Young Cage.[/vc_column_text][/vc_column_inner][/vc_row_inner][vc_row_inner][vc_column_inner width=”1/2″][vc_single_image image=”2761″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Photo by Dan Bell[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/2″][vc_single_image image=”2762″ img_size=”medium” alignment=”center” style=”vc_box_rounded” onclick=”img_link_large”][vc_column_text]Tiger Rattlesnake, North Mtn Park, Phoenix. Photo by Jim Rorabaugh[/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 Tiger Rattlesnake (Crotalus tigris) is a moderately-sized (< 959 mm TL), heavy-bodied snake with 34-52 dorsal crossbands on the body that are somewhat darker than the gray, bluish-gray or yellowish-brown to pinkish or slightly orange background color. Crossbands anteriorly on and near the neck may form blotches. Four to ten crossbands are present on the tail that are similar in color and form to those on the body. A series of small, dark lateral blotches, particularly anteriorly, alternates with the dorsal crossbands, and the crossbands may have a dark spot on their lateral edge. The venter is cream, tan, yellowish, greenish-brown, to pink with scattered darker mottling and spots. Atop the head are often dark blotches or markings that may be indistinct, or the head may be unmarked (Grismer 2002, Ernst and Ernst 2012, Goode et al. 2016).

This snake has an unusually small head and large rattles. The head length is less than 2.5 times the maximum diameter of the basal segment of the rattle. The broader than long rostral is in contact with the anterior nasal scales and the upper preoculars are undivided. Usually there is one (rarely 2) loreal scale, 11-16 supralabials, and 11-16 infralabials. The dorsal scales are heavily keeled and occur in 20-31 rows at mid-body. The subcaudals are undivided. The longest males are longer than the longest females (775 mm TL) and neonate Tiger Rattlesnakes resemble adults in color and pattern (Goode et al. 2016). Adult males have significantly longer tails than females, and that character is reliable for sexing Tiger Rattlesnakes (Goode et al. 2016). No subspecies are currently recognized; however, Tiger Rattlesnakes from different areas often differ in size and color (Crother 2012, Ernst and Ernst 2012, Goode et al. 2016), and three distinctive clades have been identified (Douglas et al. 2006).

In our area, the Tiger Rattlesnake is most likely to be confused with the Southwestern Speckled Rattlesnake (C. pyrrhus), but that species is more blotched than banded, especially anteriorly, the tail is more likely to have distinct dark banding that is bolder than the banding on the body, the head is proportionally larger and the rattles are smaller, the rostral is separated from the anterior nasal scales by one or more small scales, and the upper preoculars are divided. In Arizona and Sonora, the Southwestern Speckled Rattlesnake is a species of the Sonoran Desert that occurs largely to the west of the range of the Tiger Rattlesnake, whereas the latter species occurs in a variety of vegetation communities that extend much farther east and south than that occupied by the Southwestern Speckled Rattlesnake. Goode et al. (2016) note that both species are known from the southern end of the Bradshaw Mountains, Hieroglyphic Mountains, near Cave Creek, North Mountain, Piestewa Peak, South Mountain, Sierra Estrella, Buckeye Hills, North Maricopa Mountains, Growler Mountains, Sand Tank Mountains, and Agua Dulce Mountains in Arizona. In addition, both occur in the Pinacate region of Sonora. Range wide, the Tiger Rattlesnake occurs from south central Arizona south through much of Sonora to near the Sinaloa border. It also occurs on Isla Tiburón (Rorabaugh and Lemos-Espinal 2016).

In Arizona, the Tiger Rattlesnake is a species of rocky slopes and bajadas, primarily within the Arizona Upland Subdivision of Sonoran desertscrub. However, records also exist for the Lower Colorado River Subdivision, as well as interior chaparral, semi-desert grassland, Chihuahuan desertscrub, and oak woodland in Arizona (Lowe et al. 1986, Brennan and Holycross 2006, Goode et al. 2016, Weber et al. 2016). Within the 100-Mile Circle, it likely occurs in a similar range of habitats in Sonora (Rorabaugh and Lemos-Espinal 2016). In the Circle, the Tiger Rattlesnake occurs in mountain ranges in the Phoenix area south and west to the Sand Tanks, Sauceda and Ajo mountains and across the border into Sonora. On the east the range is bounded by the Florence Military Reservation, and the Rincon and Santa Rita Mountains, although the range of the species extends south of the border and loops around to the east to daylight again in the Peloncillo Mountains of Cochise County (Duvall et al. 1996, Goode et al. 2016, Rorabaugh and Lemos-Espinal 2016, Sullivan et al. 2017). Elevational range in the Circle varies from about 400 to 1555 m. It occurs from sea level to about 1380 m in Sonora in vegetation communities ranging from Sonoran desertscrub to semi-desert grasslands, oak woodlands, and thornscrub (Goode et al. 2016, Rorabaugh and Lemos-Espinal 2016).

At Piestewa Peak in Phoenix, Tiger Rattlesnakes did not move long distances and they frequented canyon washes and areas mid-way up steep slopes. They were often found atop, in, or near packrat nests at the base of Palo Verdes, and were active from 27 to 37^oC (Duvall et al. 1996). In the Tucson Mountains, mean home range was 3.5 ha (Beck 1995); however, elsewhere, Goode at al. (2016) recorded mean home ranges of 15.0 ha for males and 3.3 ha for females. Most Tiger Rattlesnakes are active at night, but some crepuscular and daytime activity occurs as well (Duvall et al. 1996, Brennan and Holycross 2006). Tiger Rattlesnakes have been found to stay close to rocky habitats in winter and early spring, but venture downslope into washes and bajadas later in the spring and during the summer rainy season (Beck 1995, Goode et al. 2016). These snakes enter winter dens from October to December, and then emerge in March or April (Duvall et al. 1996, Cochran and Goode 2012). Tiger Rattlesnakes are only very rarely observed above the ground in shrubs or trees.

Mating occurs from early July to late September or October. Males have occasionally been observed in combat wrestling matches during the summer. Adults measure > 512 mm SVL (males) and > 521 mm (females, Goldberg 1999, Goode et al. 2016). Females give birth to 2-6 young from late June into September. Neonates measure 210-258 mm TL (Ernst and Ernst 2012).

At Piestewa Peak, Duvall et al. (1996) found only rodent hairs in the feces of Tiger Rattlesnakes. Elsewhere, Tiger Rattlesnakes have been found to feed upon a variety of rodents and lizards. Birds are occasionally taken (Amarello and Goode 2004, Goode et al. 2016). Venom yield is relatively low, but the toxicity of Tiger Rattlesnake venom is high. Although little is known of the effects of the venom on humans, any bite from this species should be considered life threatening.

Duvall et al. (1996) believed populations of Tiger Rattlesnakes in the Phoenix Mountain Parks were small but viable. They suggested animals are killed by some recreationists, but overall the authors were optimistic about the snakes persisting in the parks. Populations of this species can be eliminated or fragmented by urban development, but in wild areas there is no reason to believe the species is in decline. The Tiger Rattlesnake is a species of least concern on the IUCN’s 2017 Red List. In Arizona, with a valid hunting license, four Tiger Rattlesnakes per year can be collected or held in possession alive or dead.

Tiger Rattlesnake (Crotalus tigris)

Description

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