There is little information available concerning communication and perception in tiger rattlesnakes. However, like other vipers, tiger rattlesnakes have heat sensing pits to detect prey and predators.
Perception Channels: visual ; infrared/heat ; chemical
Tiger rattlesnakes are classified as a species of least concern on the IUCN's Red List of Threatened Species. Habitat loss due to agricultural expansion is a potential threat, however, this species is not seriously threatened at present.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Tiger rattlesnake embryos are retained inside the female in a transparent, membranous sac, where some materials and gasses are exchanged between embryo and mother. Embryos receive fluids and sustenance from the yolk mass. Once born, neonates break through the embryonic sac and travel a short distance to a safe nook with its siblings. Young tiger rattlesnakes are not born with a rattle. Neonates have a skin cap at the tip of the tail and after every molt, a new rattle segment is added. Like all rattlesnakes, tiger rattlesnakes are ovoviviparous and thus, are well developed at birth.
Although tiger rattlesnakes are reluctant to strike, they are venomous and pose a potential threat to humans. Their venom contains a neurotoxin called Mojave toxin and a myotoxin known to cause muscle necrosis. Although venom production is low compared to other rattlesnakes, the combination of neuro- and mytoxins in their venom makes them one of the most toxic rattlesnakes known.
Negative Impacts: injures humans (bites or stings, venomous )
In general, rattlesnake skin and tail rattles are often considered valuable and are often sold as souvenirs throughout the American Southwest. Rattlesnake venom is often used in biomedical research investigating neurological diseases. Finally, tiger rattlesnakes prey upon a number of rodent species considered pests by humans throughout their geographic range.
Positive Impacts: body parts are source of valuable material; source of medicine or drug ; research and education; controls pest population
Tiger rattlesnakes feed on a number of small vertebrate species and likely help regulate their abundance and distribution. There is no information regarding parasites specific to this species.
Tiger rattlesnakes generally feed on lizards and small mammals such as pocket mice, kangaroo rats, deer mice, and woodrats. Their venom is considered the most toxic of all neotropical rattlesnakes and contains a myotoxin known to cause muscle necrosis and a neurotoxin similar to Mojave toxin. Like all venomous snakes, tiger rattlesnakes inject venom into prey through long, hollow, retractable fangs. If envenomated prey crawl into a small crevice, this species is especially suited for extracting them due to its unusually small head.
Animal Foods: mammals; reptiles
Primary Diet: carnivore (Eats terrestrial vertebrates)
Crotalus tigris (Tiger rattlesnake) is found from south central Arizona to Sonora, Mexico. This species of rattlesnake is easily found in the foothills of the Arizona Upland desert scrub but is also resident to the Interior Chaparral and Madrean Evergreen Woodland. Crotalus tigris has also been observed on Isla Tiburon in the gulf of California and was recently discovered in the southern Peloncillo Mountains of Arizona.
Biogeographic Regions: nearctic (Native )
Crotalus tigris has been observed in the foothills, rocky canyons, and ravines of deserts or mesquite grasslands from 1000 to 5000 m in elevation, throughout their geographic range. Plants native to this habitat type include cactus, mesquite, creosote bush, ocotillo, saguaro, and palo verde. Crotalus tigris also inhabit escarpments, outcroppings and cliff-faces in thorny scrub desert habitat.
Range elevation: 1,000 to 5,000 m.
Habitat Regions: terrestrial
Terrestrial Biomes: desert or dune ; savanna or grassland
There is no information regarding the average lifespan of tiger rattlesnakes.
Tiger rattlesnakes are easily identified by their small, spade shaped head, which is about 1/25 of their total body length. They have the smallest head of any rattlesnake and a large rattle. They can be gray, lavender, pink, yellowish brown, or orange. Tiger rattlesnakes are the only rattlesnake with crossbands on the anterior portion of the body, with a series of 35 to 52 gray, olive, or brown bands across the dorsum. They have 6 to 10 posterior rings, and the only distinguishable mark on the head is a dark cheek strip. Dorsal scales are keeled and in 21 to 27 rows. Individuals can weigh as much as 454 grams and can range in length from 460 to 910 mm, with an average length of 609 mm. Females have 164 to 177 ventral scales, and males have 158 to 172 ventral scales. Females have 16 to 21 caudal scales, and males have 23 to 27 caudal scales and are typically larger than females. They have relatively small eyes with an elliptical pupil. Tiger rattlesnakes are often confused with speckled rattlesnakes, western rattlesnakes, black-tailed rattlesnakes, western diamondback ratttlesnakes, and Mojave rattlesnakes.
Range mass: 454 (high) g.
Range length: 460 to 910 mm.
Average length: 609 mm.
Other Physical Features: heterothermic ; venomous
Sexual Dimorphism: male larger
There is no information available regarding predators specific to tiger rattlesnakes. Likely predators include hawks, eagles, coyotes, and other snakes. Their cryptic coloration helps camouflage them from potential predators and helps reduce risk of predation. If disturbed, they rapidly shake their rattle and may strike in defense.
Anti-predator Adaptations: cryptic
Crotalus tigris is polygynandrous, and either the male, female, or both have more than one mate within a single breeding season. Little else is known of the reproductive behavior of C. tigris. The reproductive behavior of this species is thought to be similar to the that of Crotalus atrox and Crotalus scutulatus. Copulation in viperids can take minutes, hours, or days and can occur multiple times within a couple of days.
Mating System: polygynandrous (promiscuous)
Tiger rattlesnake females follow a biennial reproductive cycle. Males follow a seasonal reproductive cycle, where sperm is stored in the vasa deferentia during winter. Breeding occurs from late May to mid August, during the summer monsoon season. Like the majority of rattlesnakes, tiger rattlesnakes are ovoviviparous. Mean clutch size for is 4 to 6 young. The smallest known sexually reproducing female measured 541 mm snout-vent length (SVL), while the smallest mature male measured 512 mm SVL.
Breeding interval: Tiger rattlesnake females mate biennially, and males mate annually.
Breeding season: Late May to mid August, during the summer monsoon season
Range number of offspring: 1 to 6.
Average number of offspring: 4 to 6.
Key Reproductive Features: iteroparous ; seasonal breeding ; sexual ; ovoviviparous ; sperm-storing
Generally, rattlesnakes invest little in offspring following birth. However, like other viperids, female tiger rattlesnakes invest in provisioning resources for developing embryos. She eats early in the pregnancy and then find a safe place to hide while providing the optimal thermal environment for development.
Parental Investment: pre-hatching/birth (Protecting: Female)
