Rattlesnakes have the following physical characteristics:
- Broad, "triangular" head
- Eyes have vertical "cat-like" pupils
- Covered in scales that are a variety of colors/patterns
- Scales are keeled with a raised ridge in the center of each
- Body is heavy or thick (or fat) in appearance
- Large tubular fangs in mouth that fold out when the mouth opens
- The mouth is like a hinge, opening 180 degrees
- Blunt tail with jointed rattle (Note: baby rattlesnakes don't have rattles and some adult snakes may break or lose their rattles)
- Typically rattlesnakes range from 3' to 4' in length
In ideal habitats where there is a constant, abundant supply of small rodents, the rattlesnake sometimes attains a length of 5 feet, but the average adult size is between 3 and 4 feet.
Rattlesnakes have a forked tongue that they flick up and down. The tongue picks microscopic airborne particles and gases from the air. When the tongue slips back into it's mouth it touches a sensitive spot on the roof of their mouth called the Jacobson's organ. This organ picks up the particles collected by the tongue and sends messages to the snakes brain identifying the scent as food, enemy, mate or other object or substance. Rattlesnakes also have external nostrils lined with olfactory cells which can pick up scent. The nostrils are mainly used for breathing.
The fork of the tongue is a directional aide. It can provide information based on which side or fork in the tongue has the strongest presence of a particular odor. This information helps the rattlesnake follow its prey or find it's way home.
Rattlesnakes pick up vibrations through their body muscles which send sound through to their jaw bones and on to their inside ear parts. Rattlesnakes do not have outer ears and therefore rely on vibrations to pick up sound.
A snakes vision can detect objects or movement from about 40 feet away, but their vision is sharper when objects are closer. A rattlesnake's pupils are elliptical, not round which enables the snake to see well in dim light. This is helpful for night hunting. Rattlesnakes are carnivorous. Instead of chewing their food, they swallow it whole. The size of the prey a rattlesnake selects is limited by its own ability to eat it based on it's own size. Rattlesnakes eat lizards and small rodents such as ground squirrels, small rabbits, rats and mice, striking rather than attempting to hold their prey.
The rattlesnake first bites it's prey to immobilize it with a toxic venom. When the hollow fangs of the rattler penetrate the victim's flesh, venom is injected as though through twin hypodermic needles. Most small prey is immediately stunned. The venom stuns and immobilizes the prey, allowing time for the rattler to swallow the victim whole. The venom also begins the digestive process as it breaks down the tissue of the prey.
Rattlesnakes have a highly-efficient digestive system which takes a lot of metabolic energy. After a rattlesnake swallows it's prey, they normally hide out while they digest their meal. Rattlesnakes become sluggish while digesting, a process that can take several days depending on the size of the meal.
The grasshopper is a leaping insect closely related to roaches and crickets. There are two types of grasshoppers: long-horned and short-horned. Long-horned grasshoppers have antennae, or feelers, about the same length as the body. Short-horned grasshoppers have antennae less than half the length of the body. Short-horned grasshoppers are often called locusts, particularly when they migrate. The 17-year-locust, however, is not a grasshopper but a cicada.There are hundreds of species of grasshoppers, distributed throughout the temperate and warmer regions of the world. They range in length from one-half inch (1.3 cm) to more than six inches (15 cm) in some tropical species. Grasshoppers are generally colored green, brown, or gray.
Scorpions are non-insect arthropods. Adults average about 2-3/8 inches in length, with the tail being longer in the males than in the females. Body color of adults varies from yellowish to tan, marked with two broad, blackish stripes on the upper surface of the abdomen. Populations in the Big Bend area may be only faintly marked or completely pale. There is a dark triangular mark on the front (anterior) portion of the head region (carapace) in the area over the (median and lateral) eyes. Younger specimens may be overall lighter in color, and basis of the pedipalps and the last segment of the body (post abdomen) is dark brown to black. The key recognition characters for this species are the slender pedipalps and the long slender tail.