I know what I saw.

It was a praying mantis, and he went swimming. On purpose. And he did it over and over again.

I have it on film.

The scene was a riffled section of the Sepulga River. There, rock outcroppings jut from the water, creating a series of tiny islands separated by shallows runs that are narrow enough you can step across them. Most of the scientists I contacted said they'd never heard of such a behavior. One called it "novel."

When I first encountered the mantis, he was hunting on one of the larger islands in the river, big enough to walk around on, but too small to pitch a tent on. While they hunt, mantises often employ a side to side swaying motion with their bodies, perhaps to distract their victims. This one was doing that, right at the edge of a little riffle.

Then, as I watched him, he suddenly leapt into the current and was carried downstream. After a moment, he started rowing with his legs and swam cross current to another island. There, he fetched up in shallow water and started prospecting around in the algae growing at the water's edge with his tiny mantis arms. He rooted around for a moment, and once again jumped into the current and worked his way to another rock.

I knew this was odd. The mantis has wings, and is a capable, if clumsy, flier. What's more, this bug was under no threat at the time. I was standing several feet away. He wasn't accidentally falling into the water in an attempt to escape trouble. He was doing it on purpose. He walked to the water's edge, sat there a moment, and dove in. At one point, he marched underwater and walked upstream through a small rapid.

As I went to fetch my camera, I called to my companions, both scientists. Unfortunately, they were paleontologists, not entomologists, and were thoroughly uninterested in my find, preferring to concentrate on the fossils we were collecting. They regarded my 20-minute obsession with this bug as a mania of sorts, a mantis mania, if you will.

Once I had my camera, the mantis did it again.

Apparently, this is not a widely recognized behavior for the mantis. Many of the mantis specialists I contacted said they had never heard of such a thing. Linda Fink, a scientist I'd previously quoted in an article about venom-spitting spiders, sent me a link to a 1972 paper that made reference to the swimming ability of the praying mantis, but primarily explored other topics. She agreed to post a query about swimming by mantises on a list-serve used by entomologists. I got several replies. One mentioned reports of pet mantises eating small, live goldfish out of bowls placed in their cages.

"I saw the posting of your question about swimming praying mantises. I don't have any experience with it but was surprised to hear that it happens," wrote a scientist in Texas. "If you get any replies from people with other links to articles about this behavior, I would very much like to see them."

Another suggested there might be fodder for a scientific paper in the behavior I'd witnessed.

"Let me check on that," wrote another. "Insect predators have been known to do amazing things. For example, dragonfly larvae love to eat fish and frog."

Then came a word from a true expert.

"I am the lead editor of the book, The Praying Mantids," wrote Frederick Prete, in the biology department at Northeastern Illinois University. "Yes, mantises will swim. Interestingly, the paper you site by Miller in 1972 is the only one that I know of. There is not any research on this behavior (though it is interesting, to be sure). In fact, I reviewed all of the mantis literature that I could find from the Egyptian "Book of the Dead" to the 1990's when I was a grad student, and Miller's paper was the only one that I saw on the topic."

Miller's paper involved both field observations and lab experiments, where mantises were plopped in vats of water and forced to swim.

"The interest of the present observations lies in the discovery of a behavior pattern which appears reliably in the laboratory under appropriate conditions in every mantid tested but which is probably of infrequent occurrence in nature," Miller wrote.

Noting that mantises are not usually near water, he concluded, "the opportunities for swimming in the wild are probably infrequent, but the survival value of this behavior is likely to be considerable."

Back to our mantis, here was a creature living his entire life right at the water's edge. He was not swimming because he had fallen in. He was jumping in on purpose. From watching him, it appeared he not only could swim, but has learned to use it as a way to move about his hunting grounds. Beyond that, he appeared to be actively hunting in shallow water, an area known to be full of aquatic insects.

Perhaps we have found a hole in the body of scientific knowledge. Take a look at the accompanying video and decide if you think this mantis is swimming intentionally. More to the point, if you see a praying mantis near the water in the future, and it looks like it is about to jump in, film it! Perhaps together we can settle the question of whether praying mantises could also be known as swimming mantises.