Here is a creature feature with two distinct species of rattlesnakes.
First we start off with a green mojave rattlesnake with a Latin name of Crotalus scutulatus. I love his pit viper slit eyes and they are called pit vipers because of a heat sensing pit between the eye and the nostril. You can see the pit right above its mouth in this picture.
One of the cool features of this snake is its slight green coloring. They are also tan in color so the green can't really be used reliably to identify them. It is easier to study their patterns to identify them.
The striped lines near the rattle are a key identifying feature of a mojave.
The slit eye and large solid diamond pattern on the back is also a good identifier. These guys are one of the most poisonous snakes in North America and of the rattle snakes they are the most venomous. Unlike many rattlesnakes this one has a neurotoxin as well as hemotoxic venom which means the venom will attack both your neurosystem (paralysis) and it will rot your flesh (hemotoxin). Fortunately these guys have rattle to warn you of their presence. As a native Arizonan for many years I've found these numerous times and its easy to avoid them because they always warn you. They just don't want to be stepped on.
Here is another species called the black-tailed rattlesnake with a Latin name of Crotalus molossus. Sometimes these ones have a greenish hue like the mojave but these guys are smaller in size and have much different patterns.
Here you can see why they are called the black-tailed rattlesnake, their eyes are also darker compared to the mojave.
Also in contrast to the mojave the black-tailed rattlesnake is way less venomous. They only have a small amount of hemotoxin and are one of the least venomous rattlesnakes in North America. If you happen to get bitten by one of these it is easily treated. Fortunately they will warn you of their presence.
Rattlesnakes are a communal species, they often gather together in caves in large piles during the winter to keep warm. This is also where they do their mating snake dances and have a unique way of sensing pheromones to avoid inbreeding, so they can actually sense if they are related to each other.
Rattlesnakes are often feared because of their venom but there are way more dangerous snakes in North America compared to these guys. Rattlesnakes are very slow and that's why they have to warn you of their presence so they don't get stepped on by a buffalo, cow or human. Their method of hunting is to wait in the desert at night and use their heat sensing pits to see if a rodent hops by, then they strike within about a 20 inch radius to snag their prey. So if you stay a good three feet away from them you won't get bitten. Compared to the highly camouflaged copperhead snake that has no rattle these guys are easy to avoid. Copperheads will bite anything near them without warning.
That's all for now, thanks for looking :-)