The Arizona Black Rattlesnake is a venomous species found in Arizona, New Mexico, and some regions of Mexico. Their black or dark grey coloration allows them to blend seamlessly into the surroundings. 

They prey on small mammals such as mice, rats, squirrels, birds, or lizards and have a unique behavior of 'tail-flagging' as a warning to potential predators. Although encounters with this species are rare, always observe them from a safe distance.

The Pacific Rattlesnake is a highly adaptable species that can camouflage in various environments. It also thrives in habitats such as grasslands, coastal areas, forests, and deserts.

This type of rattlesnake sports a blended color pattern of browns and greys. Adult sizes reach between 2 and 5 feet, making them medium- to large-sized rattlesnakes. 

This rattlesnake is a patient and precise predator that ambushes small mammals, birds, and lizards.

The Prairie Rattlesnake is a venomous pit viper exhibiting muted, earthy tones of greys and browns, camouflaging with dry landscapes. Adults typically measure between 1.5 to 3 feet in length.

This is a nominate subspecies, and it has one other subspecies called the Hopi Rattlesnake (Crotalus viridis nuntius). It is smaller, growing only up to 2 feet. Its name is derived from the Native American Hopi tribe, which lives in the habitat where the snakes live.

The South American Rattlesnake, also called Tropical Rattlesnake, presents a mix of tans and browns, beautifully designed with diamond-shaped markings along its back. Averaging between 4 and 5 feet, it sports longitudinal rows of keeled scales, lending to its rugged surface texture. 

Naturally occupying a broad range of habitats, it is typically found in forests, grasslands, and deserts across South America. This species is active the most during the early morning and dusk. Its diet primarily consists of small mammals, but it also preys on lizards in other areas.

The Pygmy Rattlesnake lives in the southeastern United States. It is small and stout, stretching only 15 to 25 inches long. Its skin displays a series of reddish-brown blotches against a grey body.

They thrive in various environments, and their diet consists of small rodents, lizards, and frogs. Their venom keeps their prey’s population in check. 

This type of rattlesnake produces cytotoxic venom that, while low in volume, is tissue-toxic and can cause hemorrhaging. The venom lacks neurotoxins but has extensive amounts of serotonin and tryptamine compounds, which led to the creation of the heart attack drug called eptifibatide4.

The Tiger Rattlesnake is a venomous species in the American Southwest and northwestern Mexico. It has bold, dark crossbands against a lighter background, resembling tiger stripes. 

This type of rattlesnake inhabits rocky terrains and scrublands, primarily surviving on a diet of small rodents, lizards, and occasionally birds.

Furthermore, they are nocturnal during summer. Before hibernating in winter, they are most active during the day and in twilight hours.

The Twin-spotted Rattlesnake is a small pit viper living in the southwestern United States and Mexico. It has a brown-to-gray palette and is a master of camouflage. 

The snake prefers living in the mountains amidst pine-oak and mixed conifer forests. It is a creature of the night and feeds on small mammals, birds, and lizards.

Western Twin Spotted Rattlesnake (Crotalus pricei ssp. pricei). Subspecies of reptile.

The Santa Catalina Rattlesnake is endemic to Santa Catalina Island in the Gulf of California. It has a non-functional rattle and light-colored skin that blends with the rocky terrain. It is primarily active at night, feeding on small mammals, birds, and lizards. 

The lack of rattling ability was hypothesized to be a stealth adaptation during hunting if they are arboreal creatures1. Observations in their natural habitat debunked this theory since these rattlesnakes are mostly terrestrial creatures.

Unfortunately, the latest IUCN assessment categorized the Santa Catalina Island Rattlesnake as critically endangered. This is an effect of multiple causes, such as its single-location existence, past threats from feral cats, illegal trade, human persecution, and dependence on a single rodent species for 70% of its diet.

The Rock Rattlesnake, or the Banded Rock Rattlesnake, is a small pit viper in the southwestern United States and northern Mexico. Its body has a pinkish-brown to dark-gray color that allows it to blend in with the surroundings.

It preys on small mammals, lizards, birds, and amphibians at night. This ovoviviparous species gives birth to 2 to 8 offspring at a time, usually in late summer or early fall. 

Despite its venom, it usually does not pose a threat to humans unless it feels threatened.

The Speckled Rattlesnake, or Mitchell’s Rattlesnake, is a venomous pit viper in the western US and Mexico. It blends in with the rocky terrain thanks to its speckled skin. 

It is active at night, feeds on small mammals, birds, and lizards, and gives birth to live young. 

When threatened, this type of rattlesnake rattles its tail and strikes with potent venom. A recent study reports its venom constitutes crotoxin and serine proteases2, which can lead to muscle weakness, vision problems, and uncontrolled bleeding.