Scorpions Spiders Mites and Ticks: Arachnida - Physical Characteristics, Diet, Behavior And Reproduction, Arachnids And People, Hair Follicle (fah-lih-kuhl) Mite (demodex Folliculorum): Species Accounts - GEOGRAPHIC RANGE, HABITAT, CONSERVATION STATUS
meaning extinction threatened risk
Arachnids are found throughout the world. About eight thousand of the ninety-seven thousand species of arachnids are found in the United States and Canada.
Arachnids live on land, in nearly every sort of habitat. Some live in freshwater.
The World Conservation Union (IUCN) lists one arachnid species as Endangered, meaning that it faces a very high risk of extinction in the wild in the near future; nine as Vulnerable, meaning that there is a high risk of its extinction in the wild; and one as Near Threatened, meaning that it is at risk of becoming threatened with extinction in the future. These and other species of arachnids are threatened by habitat destruction.
Additional Topics
Arachnids (uh-RAK-nihds) are related to sea spiders and horseshoe crabs. Among the many members of this group are ticks and mites, scorpions, spiders, and even the common harvestman, also known as daddy longlegs—all with their own distinct appearance. Despite these differences, many adult arachnids have two distinct body regions: the front portion, a sort of head area combined with a thorax…
Most arachnids live alone, except during the mating season. They engage in an amazing variety of activity to obtain food. Some spiders trap their victims in silken webs and kill them with a poisonous bite. Others ambush their prey and overpower them with their strong legs before biting them. Scorpions use their claws to capture and kill prey, or else they kill them with a venomous sting. Pseudosco…
Physical characteristics: This microscopic, wormlike, almost transparent, or see-through, parasitic mite is 0.00394 to 0.0178 inches (0.1 to 0.45 millimeters) in length. The head is distinctly separated from the body. The abdomen is finely wrinkled and tapered. Adults have eight stumplike legs, each with claws. The needlelike mouthparts are used for eating skin cells. Geographic range: These mites…
Physical characteristics: Adult wood ticks typically measure 0.08 to 0.21 inches (2 to 5.3 millimeters) in length, but females filled with blood look like plump beans and may reach a length of 0.65 inches (16.5 millimeters) and a width of 0.45 inches (11.4 millimeters). Their flat, pear-shaped bodies are covered with a tough outer skeleton. Adult females are reddish brown with a grayish white shie…
Physical characteristics: Whip spiders, or tailless whip scorpions, grow as long as 1.2 inches (30.4 millimeters). They lack the ability to produce silk and do not have venom glands. Their claws fold into a spiny basket, used to capture and hold prey. Young whip scorpions have reddish pedipalps and striped legs; the adults are uniformly brownish. The undivided carapace is wider than it is long. Th…
Physical characteristics: The small, round bodies of common harvestmen are 0.14 to 0.35 inches (3.5 to 8.9 millimeters) in length; males typically are smaller than females. The back has various patterns and ranges in color from light gray to brown, while the underside is usually light cream colored. Both body regions are divided into segments and are joined together. Two eyes directed outward are …
Physical characteristics: The stout-bodied adult zebra jumping spider ranges in size from 0.20 to 0.32 inches (5.1 to 8.1 millimeters). The two body regions are not segmented and are attached to each other by a narrow waist. The body is black with white hairs that form stripes on the abdomen. The eight legs are rather short and covered with sensory hairs. The fangs are large and usually hidden by …
Physical characteristics: The grayish brown or tan body of the cellar spider is slender and measures 0.23 to 0.3 inches (6 to 8 millimeters) in length. These spiders have eight long, clear legs. The body regions are not divided into segments and are attached to each other by a thin waist. Males are slightly shorter than females. The abdomen is long and rectangular. Geographic range: Long-bodied ce…
Physical characteristics: The book scorpion is very small, at 0.10 to 0.18 inches (2.6 to 4.5 millimeters), and looks somewhat like a pear-shaped scorpion without the stinging tail. The front of the body is olive brown to dark red and has no segments. The abdomen is olive green to pale brown and has distinct segments. The body regions are attached to one another. Their tiny claws contain venom gla…
Physical characteristics: Camel spiders are yellowish and have a leg span up to 4.7 inches (119 millimeters), but their bodies are only 2 inches (51 millimeters) long. Males are usually smaller and more slender than females and have longer legs. Both regions of the body are divided into segments. Their entire bodies are covered with hairlike bristles. They have two small eyes set on a small bump n…
Physical characteristics: Whip scorpions, also known as vinega-roons, mule killers, or grampas, are dark reddish brown or brownish black and measure 1 to 3.2 inches (25 to 80 millimeters) without the long, whiplike tail. The tail is usually carried straight over the back, lacks a stinger, and, at its base, has glands that release strong, defensive acids that smell like vinegar. The body is divided…
Physical characteristics: Emperor scorpions are shiny blue, black to greenish black, and measure 5 to 8 inches (127 to 203 millimeters) in length, including the tail. They weigh up to 1.1 ounces (35 grams), although pregnant females may weigh as much as 1.4 ounces (40 grams). The males are similar in appearance to the females, but are slightly smaller and lighter-bodied. The powerful reddish-brown…
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