What’s an Arthropod?

The word “arthropod” basically means “jointed legs,” so in the simplest of terms an arthropod is an animal with… jointed legs. You may be saying, “erm, my legs are jointed too,” which is why I’m here to discuss the additional requirements to joining the phylum Arthropoda besides just having bendable limbs.

Arthropods are invertebrates, which means they do not have a backbone. Instead of being squishy like slugs, however, arthropods have a tough, often chitinous exoskeleton that protects them and keeps them from drying out. Because this shell is not alive and therefore does not grow, all arthropods have to periodically shed their exoskeleton as they get bigger. This hard outer casing is also why arthropods have segmented bodies and jointed limbs – otherwise they’d just be little, living statues, unable to move around.

At over 1 million different species, Arthropoda is the largest phylum of animals known to mankind – which means I’m probably not running out of blog content anytime soon! Now that you know what an arthropod is, check out the rest of the blog for more on these tiny animals we all too often take for granted.

Credit to the following Flickr users for their photographs, from left to right, top to bottom: Renee Grayson, Tony Alter, prilfish, Brian Tomlinson, U.S. Fish and Wildlife Service Northeast Region, Henry Burrows, Katja Schulz, Aah-Yeah, prof.bizzarro, Thomas Shahan, cifraser, and Aleksey Gnilenkov