New Mexico: Gigantic Grasshopper

2019 February 3

Continuing down the slot canyon[1] in New Mexico on December 2, 2018, Sandy spotted something.

Canyon.spotted.something

It was this great big nearly-wingless grasshopper, crawling up the canyon wall.
NM.hopper.dorsal.on.rock

It didn’t make any particular attempt to get away, and was easy to pick up.

NM.hopper.facing

As you can see from the comparison with the size of Sandy’s hand, this thing was approaching two inches long, which even for a grasshopper is pretty darned big.

NM.hopper.side.on.hand

Between the size, and the lack of interest in defending itself, I suspect that this is one of the Lubber grasshoppers, in the family Romaleinae. These are large, slow-moving grasshoppers, many of which are wingless, that don’t get eaten because they are toxic. It really looks like toxicity pays off for desert animals, since so many of the insects we saw were noxious to eat.

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[1] Getting a slot canyon like this depends on both the correct climate, and the correct geology. I think the rock is a breccia (angular particles stuck together), and I think in this case the rock fragments are cemented together with gypsum (hydrated calcium sulfate). The rock is strong when dry (so the walls don’t cave in), but because the cementing gypsum is slightly soluble in water, it erodes quickly when wet. It looks like the channel deepened pretty rapidly when it first formed. Here is a spot where a large stick is wedged into the channel about 15 feet over our heads.

Canyon.wedged.stick

I can only think of a few ways it could have gotten way up there. One is that it got wedged in back when the channel was forming, and then continuing erosion dropped the floor of the canyon well below it before it could be broken free or rot away. In this climate, I suppose it could have stayed up there for a long time.

Of course, there are two other ways it could have gotten there. One is that some people might have wedged it in there for some reason (although it would have been a lot of work for no obvious reason). Another is that maybe the water really does run that deep when the canyon floods. This is actually not unbelievable, considering that we also found a number of out-of-place black rocks that clearly weren’t part of the original rock:

Canyon.black.rocks

We eventually found the source of these rocks, in an outcropping way up at the head of the canyon, several hundred yards further along.

Canyon.black.rock.source

This means that when the canyon floods, the current is easily strong enough to carry boulders that weigh hundreds of pounds, implying that it is not only very fast, but also pretty deep.

I’ve heard that you should never go into one of these canyons if there is any chance of rain anywhere nearby, because they can flood very fast and you can’t get out in time. After seeing this one, I believe it.

2 Responses
  1. March 6, 2019

    Not sure if it was true where you were, but where I used to take our kids to find fossils (SoCal near the Arizona border) was ocean floor only a few million years ago.

  2. March 7, 2019

    Yes, the vast majority of New Mexico looks like it was shallow water through the Permian, and that it got cut off from the rest of the ocean and dried out in the early Triassic to leave all the evaporite deposits. There were a fair number of fossils, although we didn’t find anything that was simultaneously (a) really good, (b) portable, and (c) legal to collect.

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