Types of arthropods include crustaceans, spiders and their kin, and insects. These are animals with a segmented exoskeleton and many legs. Most animals on earth are arthropods. In order to grow, arthropods need to moult their exoskeletons from time to time.
Arachnids include spiders, ticks, scorpions, harvestmen, solpugids and mites, with spiders being the most numerous of this class of arthropods. All of them have eight legs and two bodily segments, the cephalothorax and the abdomen. They lack both antennae and wings, but some breathe by way of book lungs. These are organs that resemble the pages of a book.
Many arachnids can produce silk, and spiders are especially known for the intricate webs they weave. Most arachnids are carnivores and eat insects and other small arthropods. Larger arachnids, such as large scorpions, are able to take prey such as mice or snakes.
Crustaceans include animals such as lobster, shrimp, crayfish, krill and crabs. Many of these animals are aquatic and covered with a hard carapace. Every body segment is made to hold a pair of legs. Crustaceans also have one or more compound or single eyes.
Insects are by far the biggest class of arthropod. Most insects have bodies made up of three segments, antennae and wings.