Cockroach vs Beetle: The 5 Key Differences

Written by Brandi Allred
Updated: January 29, 2022
Image Credit Mark Brandon/Shutterstock.com
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If you’ve seen a medium-sized insect scurrying about in your home, you may be wondering whether it’s a cockroach or a beetle. Though they’re both insects with similar appearances, beetles and cockroaches are actually members of two different Orders. Cockroaches belong to the Blattodea Order, while Beetles belong to the Coleoptera Order. Both types of insects live all over the world, with the exception of Antarctica. While there are only about 4,500 species of cockroach—there are over 400,000 species of beetle.

Here, we’ll take a look at just what differentiates cockroaches from beetles, and how you can tell the difference. We’ll go over each of the key characteristics that each insect has in common, and how they differ. Then, we’ll examine a few other species of insect that are often confused with cockroaches. 

Are Cockroaches and Beetles the Same Thing?

Cockroach vs. Beetle
Beetles and cockroaches can look similar, but they are different types of insects.

A-Z-Animals.com

They may look similar at first glance, but cockroaches and beetles are in fact different bugs. Not only are they different species; they’re actually different Orders of insects. Comparing a beetle to a cockroach is a little bit like comparing a deer to a sheep; they share many characteristics, but there are also some pretty significant differences between the two. 

Because both beetles and cockroaches live in homes and urban settings, they’re often confused for one another. Distinguishing the two is important, as the presence of a cockroach may indicate a problem infestation, while beetles are generally harmless.

Is It a Beetle or a Cockroach? 5 Key Differences

Types of beetles - black caterpillar hunter beetle
With. more than 400,000 species, there are around 100-fold as many beetles as cockroaches.

iStock.com/MichaelRLopez

The key difference between cockroaches and caterpillars is that cockroaches generally have longer antennae. In addition, cockroaches have distinctive spikes on their legs while beetles have shorter legs. The two bugs also have different lifecycles, with cockroaches beginning as eggs while beetles start out as grubs.

Beetles and roaches may look similar, but they’re very different bugs. There’s a lot of variation between species; the Australian rhinoceros cockroach looks very different from the American cockroach. Luckily, there are only a few species of roach common to urban areas, and none of them look very much like a beetle. Once you’ve learned how each type of insect is different, you should be able to distinguish the two without a problem—regardless of species.

1. Body Shape

All species of common cockroach have the same general body shape: flattened, narrow, and ovoid. Beetles, on the other hand, tend to be a little thicker, particularly around the abdomen. Additionally, many species of beetle exhibit longitudinal lines on their body—like stripes running from head to rear. While cockroaches don’t have these lines; instead they have either distinct coloring or full-body wings.

Further, beetles’ heads are very distinctly segmented from the rest of their body; there’s a noticeable gap between the head and the thorax. In cockroaches, the head, thorax, and body form one smooth line with no gaps. Cockroaches also have a hard shield called a pronotum covering the tops of their heads.

2. Antennae

Wood Roch - Cockraoch on Wood
Cockroaches have long antennae.

iStock.com/frank600

One of the easiest ways to tell cockroaches and beetles apart is by looking at their antenna. Beetles have relatively short antennae, and visible pincer-like mouthparts. In contrast, cockroaches have extremely long antennae that can reach the length of the rest of their body. Their antennae are long, thin, and constantly in motion. Beetle antennae are rarely very long, and they don’t move nearly as much as cockroach antennae.

3. Legs

Wood Roach vs Cockroach - Pennsylvania wood roach
Cockroaches have distinctive spikes on their legs while beetle legs are generally shorter.

Melinda Fawver/Shutterstock.com

Both cockroaches and beetles have six legs; two towards the front of the body, attached to the thorax, and four towards the back of the body, attached to the abdomen. Cockroaches have relatively long legs with distinct, visible spikes. The spikes point away from the body and look like long, wickedly sharp leg hairs; they’re mainly used for grooming, and gripping smooth surfaces.

Beetles, on the other hand, have shorter legs that tend to bend closer to the body. And—they don’t have hard spikes like cockroaches. Beetle legs are often thicker closer to the body, and may even have an additional bend that cockroach legs don’t have. Beetles tend to be slower than cockroaches; they’re more likely to be ground dwellers and have less need for fast-moving legs.

4. Movement

Types of beetles - dung beetle
While cockroaches are nocturnal and rely on quickness, beetles are generally slow.

Mike Laptev/Shutterstock.com

When trying to determine whether the bug you saw is a cockroach or a beetle, one of the biggest tells is speed. Cockroaches are nocturnal; they scatter when the lights go on. They depend on their ability to flee predators, once they’ve gotten away, they usually tuck themselves into tiny, safe crevices. Beetles, in contrast, don’t rely on speed.

Where the cockroach is fast, the beetle is slow. Watching a beetle run a race would be a little bit like watching paint dry. Their movements are slow and deliberate—something that pretty much never characterizes a cockroach. So, if you’re asking yourself ‘was that a cockroach or a beetle?’, think about how fast the bug moved.

5. Life Cycle

Baby Cockroach - Cockroach Lifecycle
Cockroaches start life in eggs; beetles begin as grubs.

VectorMine/Shutterstock.com

But what if you’ve found a grub, or an egg case, and you want to know if it’s a beetle or a cockroach? Well, the answer is simple: beetles develop from grubs (larvae), and cockroaches hatch from eggs encased in egg cases. Beetle grubs look similar to maggots, or any other larval insect. They’re usually found outside, in moist earth or rotting vegetation.

Unlike beetles, cockroaches start out as eggs. Some incubate inside female cockroaches, who in turn give birth to live young, while some develop in egg cases. When cockroaches hatch, they’re known as nymphs, and resemble smaller, paler versions of the adults.

Other Bugs Often Mistaken For Cockroaches

With so many species of cockroaches prevalent all over the world, it’s no wonder we mistake lots of bugs for cockroaches. In addition to beetles, a few of the most common cases of mistaken identity come from crickets, water bugs, bed bugs, and termites. The important thing to remember is that cockroaches have narrow, ovoid bodies—and long antennae. Unlike water bugs and termites, they don’t have pincers. And, in contrast to crickets, they don’t have powerful back legs designed for jumping. 

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About the Author

I am a professional writer by day and a fiction writer by night. My nonfiction work focuses on animals, nature, and conservation. I hold degrees in English and Anthropology, and spend my free time writing horror, scifi, and fantasy stories.