Cockroach Legs: Why Are Roaches So Fast?

Photo of cockroach legs.  Close up of German roach where spines on legs are visible
Adult German cockroach legs

Cockroaches are built for running with streamlined and aerodynamic bodies. When running, cockroach legs are bent at the knees, allowing their legs to work more efficiently and scurry across your kitchen floor at what looks like a frighteningly fast speed.

In this guide, you will learn the anatomy of the cockroach leg, how it works, how fast these pests can run, and how cockroach legs can actually help reduce an infestation. 

Written by: A O’Neill, Licensed Pest Management Professional

How Many Legs Does a Cockroach Have?

Cockroaches have three pairs of legs, so six legs in total. There are three sections to the body of a cockroach: the head, thorax, and abdomen, and each pair of legs attach to a specific part of the thorax, which is how they get their name.

All pairs of cockroach legs are similar in structure, but each has a different function and increases in length from the front (anterior) to the back (posterior).

The first pair are the prothoracic legs, these are situated closest to the roach’s head on the thorax and are the shortest of the three pairs.

The roach uses these to stop and come to a standstill when running. This pair of legs carries most of the roach’s weight and picks up insecticide residue on surfaces, which we will look at further below. 

The second pair are the mesothoracic legs which are the middle legs that the roach uses to either increase speed or slow itself down by using back and forth movements. 

The third pair is the metathoracic legs which are the back or hind legs and carry the least amount of body weight. They are the most powerful and the longest of the three pairs, and the roach uses these to propel itself forward. 

Each leg has the following five parts: 

Coxa – upper part of the leg and attaches the leg to the thorax. It is also attached to the trochanter.

Trochanter – this is a small segment that we would call a knee, which attaches to the femur.

Femur – this is the equivalent of our thigh bone and is long and covered in spines.

Tibia – this is the shin bone which is also covered in spines and attaches to:

Tarsus – this region of the roach’s leg is important for reasons explained further down. The tarsus acts as the ankle and connects to the pretarsus (foot) that segments into five tarsomeres, each with a tarsal pad (arolium).

Each pad acts like a suction cup so the roach can climb all types of surfaces. The fifth tarsomere has a claw or hook beside the pad which also helps the roach to cling to different surfaces so it can climb them.  

Basically, when the roach runs, its legs push against the ground, causing friction and creating resistance. The cockroach pushes off the ground with its feet and propels itself forwards. The legs of a cockroach are flexible, enabling it to easily change direction and scurry into one of many hiding places.

How Fast Can a Roach Run?

The fastest speed recorded by a roach, which was in fact an American cockroach, was 50 body lengths per second, and that is equivalent to running at 5.4 km/hr (3.36 mph).[1]

When a cockroach runs at full speed, its legs move back and forth about 27 times per second.  Now you know how they can disappear out of sight so quickly. 

Can Cockroaches Regrow Their Legs?

Yes, Cockroaches can regenerate their legs if, for some reason, they become detached from their body. 

Cockroach leg regrowth has been studied for well over 100 years, and these studies reveal that the legs grow back to full size within 18 – 28 weeks.[2]  

At first, the new limbs are smaller than the old ones, but as time goes by, they become larger and stronger until they reach full size. You may see a roach with a leg missing, but take a look at these bugs that look like roaches to be sure it definitely is a roach you have seen.

Can Cockroaches Crawl up Walls and Walk Upside Down on Ceilings?

Roaches climbing up a door and wall
Roaches climbing up a door and wall

Yes, they can! As you read above, cockroaches have some very special features on their feet (pretarsal arolia and tarsal pulvilli) that help them grip smooth and rough surfaces as well as crawl downwards, upwards, and upside-down enabling them to climb walls and walk upside down on ceilings with ease. 

If you want to see more images of this, take a look at my pictures of cockroaches page. 

However, there is a type of cockroach with underdeveloped pads, and that is the Oriental roach. This species cannot climb smooth surfaces which is why you usually find them trapped in sinks and bathtubs.

Cockroach Legs and Reducing an Infestation

Seeing roaches scurrying up your wall is bad enough, but there’s also the problem that roaches crawl through filthy environments and the spines and the tarsal pads pick up bacteria meaning roaches can be harmful to our health.

As the roach crawls, these pathogenic organisms transfer from the spines and pads onto your kitchen countertops or any food left out, causing contamination. 

Read: What attracts roaches

There’s worse to come. When grooming their legs, they ingest the bacteria they picked up and later regurgitate it with other digestive fluids onto whatever surface they are crawling on – including food. 

There is some good news, however, but not for the cockroach.  I mentioned above that insecticides can stick to the roach’s legs. Well, this is a disadvantage of the cockroach leg having spines and pads on it because it picks up insecticide residue (powder, dust, and bait) put on any treated surfaces they crawl on. 

This is a major benefit when trying to control a cockroach infestation. As well as ingesting the bacteria picked up, the adult cockroach will also consume the toxic insecticide when it grooms itself, causing it to die. This not only kills that roach but also kills any of the other roaches that eat it.

However, small nymphs such as German cockroach nymphs might not weigh enough or have large enough pads to pick up any insecticide.

Cockroaches are one of the fastest pests when it comes to running and you now have a better understanding of how they move with such great speed. If you do see roaches scurrying around in your home, you need to get rid of them fast as they breed quickly and can be difficult to get rid of.  

For a free no-obligation local pest control quote, fill in the form below to get started.  While you’re here you might also want to read my how to get rid of cockroaches without an exterminator guide.  This gives you tips on what to do and how to prevent them from re-entering your home.   

[1] https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.547.9445&rep=rep1&type=pdf

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4732745