All Insects Share These Characteristics

bug dog bug 1Every time I go for a run in the Rocky Mountains with my owners I smell lots of tiny little bugs and critters.  Sometimes I have a big spider fall on my back as I jump through the bushes.  Other times I see butterflies soaring over my head when I jump in a meadow of wildflowers.  I even see little creatures floating in and on the water when I slurp up some water from a pond or stream.

There are so many different kinds of these little critters, yet most of them are called insects.  It is hard to believe that such different creatures can all have certain things in common, but they do.

All Insects Share These Characteristics

In general, what makes an insect an insect?  All insects have the following in common:

  • Insects have an exoskeleton – a hard shell like covering on the outside of its body.
  • The body itself is composed of three parts: head, thorax, and abdomen.
  • They have six legs.
  • They have one pair of antennae.

Not All Tiny Creatures Are Insects

I think of all tiny creatures that I see as bugs or insects, but that is not in fact tree.  There are some little creatures that are the size of bugs, but are not actually insects because they do not have all of these characteristics.

One of the tiny creatures that is not an insects is an earthworms.  An earthworm is an invertebrate (meaning that it has no backbone), but it does not have the characteristics of insects.  Read here for information about what happens if you cut a worm in two.

Here is  little test – are these insects or not?


dog spider

NO.  Spiders have eight legs and so are not insects.


insects, bugs, grasshopper

YES.  Grasshoppers are insects.


bugs, insects, painted lady butterfly



bugs, insects, pill bug

NO.  Pill bugs have more than six legs.