Two serpents, heads raised high above the grass, sway side by side before rapidly trying to loop around each other, both snakes struggling to slam their opponent into the ground. This is no mating dance, and the animals aren't playing around – these male-on-male wrestling matches are serious battles for dominance.

This clash of cottonmouth snakes was filmed recently by Charlie Bruggerman, a kayaker and fisherman who video-blogs his trips through the Tidewater region of southeastern Virginia. Bruggerman noticed the duelling pair while photographing birds in Back Bay National Wildlife Refuge. "They were right next to the path," he said in an email, "you couldn't miss them standing up about two feet."

This sort of behaviour is often confused with serpentine mating rituals, and there are some similarities: courting male and female snakes do sometimes raise their bodies up together, though not in the violent manner seen here.

"Snake mating is generally a subtle and low-key interaction," explained wildlife ecologist David Steen in an email. "Mating snakes will also typically have their tails wrapped around each other as the male inserts his hemipene into the female's cloaca."

As you can see in this video of courting cottonmouths, snake sex is a much more sensual experience:

Wrestling matches are extremely common among animals, from head-to-head moose combat to lizards brawling in the streets. But these are not usually fights to the death.

"The goal of these fights is not to injure or kill each other; otherwise this behaviour would be extremely risky and there would be a ton of dead animals everywhere," Steen explained. "The goal is to establish dominance."

The winner of this cottonmouth combat will likely have a much better shot at reproducing with female snakes in the vicinity. A fight like this might be fairly quick – this bout lasted only about five minutes, according to Bruggerman – or it could go on for hours. At the end of the video, you can see one snake pin the other quite decisively to the ground, thus claiming victory.

Bruggerman considers himself lucky to have witnessed the behaviour. Snake fights are not commonly observed, and even less often caught on such high-quality video. "Back Bay NWR is full of cottonmouths. I see them almost every time I go there," he said. "I have seen the 'dominance dance' once before, a couple of years ago. This time, I had a Nikon D500 with a 150-600mm lens." That's fortunate for him, and for us!

Snakes all around the world are known to perform dominance battles like this one (boas and pythons even have "pelvic spurs" that they use to scrape and poke at each other), but snakes are pretty secretive, and it's been a challenge for herpetologists to investigate such behaviour.

"It is rarely seen in the wild and this limits our ability to learn much about it in nature," Steen said. "That said, a number of laboratory experiments have been conducted with captive animals that have helped us understand the behaviours associated with snake fighting."



Top header image: Pauline Rosenberg/Flickr