Fun Facts: Butterfly or Moth?

Have you ever caught a glimpse of something flutter by, only to wonder what it was - moth or butterfly? Most of us have, but many of us can’t tell which it was. Although some exceptions to these guidelines can make telling them apart tricky, it is usually pretty simple. Here are some tips to identify whether you are seeing a moth or a butterfly.

Moths and butterflies are both in the insect order Lepidoptera, with large wings covered in powder-like scales. They both develop from egg to larva (caterpillars) to pupa - but moths emerge as adults from a silk-covered cocoon, and butterflies emerge from a hard, smooth chrysalis.

Most of the time, it is enough to think of butterflies as just fancy moths. Butterflies are typically brightly coloured, and moths are usually drab in colouring. Of course, some moths are intricate and beautiful, and some butterflies can be terribly dull! You might also be able to tell them apart just by looking at their wings; butterflies tend to fold their wings vertically in the air, whereas moths tend to drape their wings down against their back or side.

  Butterflies are brightly coloured, and hold their wings up vertically into the air

Butterflies are brightly coloured, and hold their wings up vertically into the air

  Moths are often dull in colour, and drape their wings against their back

Moths are often dull in colour, and drape their wings against their back

The time of day you see them can also be an indicator. Most butterflies are diurnal, or active during the day, and most moths nocturnal, or most active at night. So the next time you see something land on a flower on a warm spring afternoon, it is likely a butterfly. If you are sitting outside in the evening watching it hover around your lamp, it is probably a moth.

These can all be helpful observations for identification, but the best way to tell them apart is generally by looking at their antennae. Almost all butterflies have antennae that are club-shaped; each one will be a long shaft with a small bulb at the end. Moths can have different types of antennae, most commonly feathered or tapered, but they will almost never be club-shaped like a butterfly’s.  

  Butterflies have club-shaped antennae

Butterflies have club-shaped antennae

  Some butterflies, such as "blues" like this one, may look like moths, but can still be distinguished by the bulb on top of the antennae

Some butterflies, such as "blues" like this one, may look like moths, but can still be distinguished by the bulb on top of the antennae

  Moths may have thin, tapered antennae

Moths may have thin, tapered antennae

  Or they may have feathered antennae, like this Polyphemus moth commonly found in Alberta

Or they may have feathered antennae, like this Polyphemus moth commonly found in Alberta