Arachnid – Spiders, Ticks, and Scorpions…Watch Out!


Photo via Flickr.

Arachnids are all around us in the Rocky Mountains and the world.  They include fun animals like spiders, ticks, and scorpions.

I remember as kid first learning about what an arachnid is at a school camp.  The teacher made it fun and did a good job of explaining to us what arachnids are.  The best part was that I got to hold a tarantula on my hand!  Well, here is a little bit of information about what is an arachnid and common characteristics that they all share.

What Is An Arachnid?

They are a class of animal that makes up the second largest group of land animals, after insects.  There are 70,000 different species of them!

Contrary to what people often think, they are mostly harmless to people.  The same can’t be said for insects though as most arachnids eat insects.


All arachnids, including this scorpion, have 8 legs. Photo via Flickr.

What Characteristics Do Most Arachnids Share?

Most have two body parts – a combined head and thorax (called a cephalothorax), and an abdomen.

Have a hardened exoskeleton, meaning that their skeleton is on the outside of their body.

They have jointed appendages – they can bend their legs.

Most have eight legs – think of spiders and ticks with 8 legs.

Most are flesh eating predators.  They feed by piercing their prey with their fangs and inserting venom.  The venom kills the prey and digests the food so that the arachnid can just sip it up when it is ready to eat.


How many legs does this tick have? Are they jointed – can they bend? Photo via Flickr.

How Is An Arachnid And An Insect Different?

I always think of any of the tiny animals that crawl and fly around as bugs.  This includes flys, ladybugs, caterpillars, and spiders.  However, technically this is not true because all of these tiny animals are actually quite different.

Both are members of the invertebrate phylum (no backbone), which is different than vertebrates (animals with backbones such as mammals, birds, and reptiles).  However, they belong to different classes.

One quick and easy difference is that insects have 6 legs and arachnids have 8 legs.