Reader Question About Ant Mounds

We have a question for the Consult-Ant today:


I have an ant question!

Over the years I have seen an unusual type of ant mound. It is a long, linear “mound”; actually a series of small mounds connected by tunnels of soil particles. The unusual thing about them is that extend in a straight line for several feet. Somewhere I heard these called “railroad ants”, but I don’t know if that is more than just a local name or description of the straight-as-a-string nest mound. I’d appreciate any information you might have about them, like scientific name or a reference where I could learn more. Thanks.



Since you don’t tell me where you are from, I’m going to take a wild guess and suggest you might possibly be talking about a type of fire ant. Fire ants tend to build loose mounds that are sometimes long and narrow. (Except if they were fire ants, you’d probably know about them already).

Does the mound you are seeing look like the second photograph in this post?

If not, please let me know where you are located, which will help me narrow the choices. Also, roughly how big are the structures?

Anyone out there heard this common name and know more about it? Please let us know if you have some ideas.

(Note: As I mentioned previously, I have been the “Consult-Ant” on the Leaping from the Box website. I answer questions about ants and ant farms. From now on I will post the answers here, and when Karen has time she will also post the answers on her site.)

6 Replies to “Reader Question About Ant Mounds”

  1. This also reminds me of the African ants that create highways, then build up the sides with dirt, then eventually roof them over with leaves and dirt etc. Maybe there is a highway inside? 😀

  2. Thanks for your reply.

    I live in Athens, Georgia. The mounds I have seen are on paths in wooded areas. I don’t think they are Imported Fire Ant mounds. The fire ants here build in sunny, disturbed areas, like lawns and are much larger. The “railroad ant” mounds are much smaller than fire ant mounds, are in shady, wooded paths and distinctly linear. They are arranged like this: ***———–**——–***——–*
    The “*” indicates a small mound with an opening at the top and the “-” indicates what I think might be a surface tunnel connecting to the next small mound. The number of “*” just indicates that the size of the small mounds is variable. These are the size of the mounds I sometimes see appearing in the spaces between sidewalk pavements around town. The total length of mound(s) plus tunnels is variable, but can be 4-5 feet. The mounds are a few inches long and less than an inch high; the tunnels are variable length and a fraction of an inch wide and high. What is unusual is the straightness of the mound-tunnel complex; they look like they were laid out by a surveyor — straight as a string. Sometimes I see ants that have built mounds in the sidewalk cracks or spaces that are forced to be linear because that’s where access to the soil is. The “railroad ant” mounds look like these “sidewalk ants” but with the cement blocks removed.

    I hope this description is better than my previous one.

  3. Yes, this is a very helpful description. I have a couple of ideas, but let me look up a few things before I respond.

  4. Dale-

    Your assessment that the ants are similar to sidewalk ants might be a good one. Sidewalk ants belong to the genus Forelius, and they do occur in your area. I wasn’t able to find anything specific about their nesting habits there, though.

    If you want to find out more, I would suggest two options. First of all, if you can catch a few of the ants, the School of Ants project is accepting ants from the public for identification. The link will take you to instructions as to how to send in samples.

    Or, if you can get some good photographs, BugGuide is a wonderful resource as well.

    Thank you for taking time to write. If I find out anything more, I will definitely let you know.

  5. I’ve noticed the same thing. I live in central Texas and have seen the same profile: a linear string of very small, connected mounds. Mine is around 6 feet long!

  6. I see the same ant tunnels here too 5-6 feet long with small openings along the way. This is in central Florida.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.