What is an Arthropod?

Are you ready, Defenders? Because we're about to discuss the BIGGEST GROUP IN THE ANIMAL KINGDOM! That's right - this page is all about Arthropods! What's an Arthropod you ask? Well you're already familiar with many of these creatures, there are almost no places on earth you can live without an arthropod nearby! This group of animals are known for their exoskeletons, segmented bodies, and molting to replace their exoskeletons. Arthropods are the largest group in the animal kingdom, and made up of a diverse array of invertebrates. There are 5 main groups of Arthropods:

  • Trilobites -  an extinct group that lived for roughly 300 Million Years, between 520 - 250 Million Years Ago. Most trilobite fossils look similar to a horseshoe crab, and these were marine arthropods that lived a variety of lifestyles.
  • Chelicerates - This group is mainly filled with our 8 legged friends known as arachnids, however it also includes horseshoe crabs, and sea spiders, which technically are not arachnids themselves! Many of these arthropods have a form of venom, and they make use of almost all feeding strategies from being predators, scavenging, and even some are parasitic!
  • Myriapods - If it's got a whole bunch of legs, it's probably a Myriapod! This group contains centipedes and millipedes, along with a few other lesser known groups like Pauropods. These arthropods are known for their many limbs, as well as their ghoulish appearances. In some places in China, centipedes are even grilled and sold as a tasty snack!
  • Crustaceans - One of the most common known arthropod groups, by name and by the members it contains. Crustaceans are often referred to as "shellfish" in the food industry, as this group includes crabs, lobsters, crayfish, and shrimp. What many don't know, is that woodlice and barnacles are actually crustaceans too!

Within those groups, there are estimated between 1 and 10 million different species! Not only is this group the biggest and most diverse in the animal kingdom, but they account for over 80% of all life on earth! That means 4 out of every 5 living creatures is an arthropod!

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