Ant behavior: May 2012 Archives


My buddy and I were walking back into our office today and he noticed a brown spot in the grass. Upon closer examination, we realized that it was a giant pile of ants and could not figure out what they were doing. We just wanted to know why they were all grouped up like that and what they were doing. Please let us know if you have any input - it would be greatly appreciated.

Thank you,





Hello Val,

These are the common pavement ant, variously known as Tetramorium caespitum or here at Ant Web (pending publication of research on its classification) Tetramorium species E. Originally from Europe, it is now established across the northern half or so of the US and in southern Canada, in urban areas. It has also made it to another outpost of European culture, in South America, south of Buenos Aires, Argentina! This species is famous for its pitched, but rarely lethal, territorial battles among neighboring colonies and you have found a particularly good example of this behavior.


James C. Trager of the AntAsk Team

at 11:30pm, 20 May 2012, Gerald wrote:
This year at my home there are no ants in my yard, garden, nowhere
In Cathedral City, Ca.
Do you think we are going to have a big earth quake

at 12:30pm, 21 May 2012, Jesse wrote:
Dear Gerald,


Just joking. Ants have not been shown to be able to predict earthquakes. During careful behavioral observations of the harvester ants Messor pergandei, John Lighton and Frances Duncan noted no change in activity before, during, or up to three days after a magnitude 7.4 earthquake in the Mojave desert in 1992 (they published the report in 2005 in the Journal of Experimental Biology - doi: 10.1242/​jeb.01735). The authors conclude that "anecdotal accounts of the effects of earthquakes or their precursors on insect behavior should be interpreted with caution."

It is more likely that ant activity is very low because of recent weather patterns, or your town (or an overzealous neighbor) has used broadcast insecticides to get rid of some type of insect pest. You might consider contacting your town hall to see if there have been any recent applications of pesticides, for mosquitos, or a particular crop pest, for example.

Hope this helps!
Jesse Czekanski-Moir & the AntAsk Team

at 1:06pm 21 May 2012 Gerald wrote:
Well this morning we had 3.7 in Kern county

at 1:45pm 21 May 2012 Jesse wrote:
Hey Gerald,

That's interesting. It's possible that there were some different cues leading up to your earthquake that weren't present for the 1992 earthquake Lighton and Duncan observed. In the case of both your observations and theirs, this situation underscores the need for replication in science. In your case, I would caution that "correlation does not imply causation," and that without controlled experiments and/or a lot of careful observations, we can't come to any conclusions with respect to ants' ability to predict earthquakes. In the broader, philosophy of science scheme of things, you failed to falsify the hypothesis that ants can predict earthquakes, but Lighton and Duncan's observations falsified that hypothesis. Again, they're both one-time observations, but you or someone else would need to gather more data to cast Lighton and Duncan's findings in doubt.

I'm sure you get quite a few earthquakes in your area, so it would be great to initiate some citizen science that involves ant monitoring. It would be a great way, for example, to get kids involved in science and natural history. If you were able to coordinate with some local summer camps, for example, you could gather quite a bit of useful data with respect to this very practical question, and give kids a taste of what it's like to do science that's important to their community.


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