The Art of Gentle Combat

Understanding the Non-violent Sparring of Panamint Rattlesnakes

Two male Panamint Rattlesnakes (orange rattlesnakes with reddish-brown blotches and bands) engaged in combat. About one-third of their bodies are lifted off the ground, curved in parallel Cs, with their noses pointed in the same direction.
Male Panamint Rattlesnakes spar in a popular basking area while a female observes in the background.

Each spring, after six months of cold weather in the southwesternmost Great Basin Desert, Panamint Rattlesnakes emerge from rocky dens and knot together in the sun to bask, spar, and mate. And each spring, when I observe sparring or “combat rituals” between male Panamint Rattlesnakes, what strikes me most is how gentle such “combat” is. It’s sometimes difficult to distinguish between mating, sparring, and basking, but easy to tell that relationships between male rattlesnakes are beyond my ken.

Panamint Rattlesnakes in my region engage in “communal hyperfidelity.”1 They gather in specific places — near or in large outcrops or slabs of stone — during essential parts of their life cycles. They gather together to overwinter. (Great Basin winters can be brutally cold and snow-filled.) Many remain together after they emerge in spring, a time that overlaps with mating season. Females may then linger to gestate. (Large slabs of stone offer thermal mass, storing daytime warmth and nighttime cool. Females who lie on those stones or in their shade can maintain more stable temperatures in low-humidity climes, where temperatures change rapidly with sunlight.) Altogether, Panamint Rattlesnakes here may spend more than half their lives in others’ company. “Together” may be their default condition.

In spring, large adult male Panamint Rattlesnakes engage in combat near basking areas. When males spar, they rise up together as parallel columns of snake. The lower halves of their bodies may entwine, or not. They may face each other, or they may point their noses in the same direction and curve themselves in parallel Cs. Eventually, they clinch and try to wrestle each other to the ground, but usually they anticipate each others’ movements so well that their upper halves might not meet for some time.

A frowsy male Panamint Rattlesnake (orange rattlesnakes with reddish-brown blotches and bands) rising out of bitterbrush and looking at the photographer.
A frowsy male rises out of bitterbrush on the veranda, awoken by another male who climbed over his head through the bushes, apparently to avoid him and the second snake he is with. (A large whipsnake, whose blurred coils are on the upper right, has joined the rattlesnake males on the veranda.)

If you haven’t seen a rattlesnake combat ritual, imagine a thumb wrestling match in which each thumb tries to pin or overturn the other thumb. Imagine the thumbs are intelligent, long, flexible, graceful, preternaturally capable of anticipating each other, and — although they are entirely independent of hands — perfectly choreographed.

Eventually, one rattlesnake wraps around the other and brings him down. The “winner” might remain in place or head for the nearest snake gathering. The “loser” might leave. If no one definitively won, both snakes might sink down again and coil together in bitterbrush until another snake goes past and startles them.

That’s all. No slashes, bites, or head butts. The consequences of defeat seem to be exhaustion or temporary exile.

Why are sparring matches so gentle? Why spar at all?

If they survive, rattlesnakes take years to reach reproductive age. En route, they learn how to navigate, how to hunt, when to hide and when to rattle. They evade freezing, overheating, and armadas of predators, from roadrunners working in pairs to red-tailed hawks plunging from the sky.

Two male Panamint Rattlesnakes (orange rattlesnakes with reddish-brown blotches and bands) engaged in combat. About one-third of their bodies are lifted off the ground, curved and partially entwined.
After waking, the frowsy male in the previous photo begins to spar again with another male with whom he was previously resting.

Most female rattlesnakes who reach adulthood reproduce only every other year.2 They gestate for months, bear their young live, and care for them after birth.3 For females, mating and reproduction represent careful investments. In turn, for males, chances to court and mate are rare and valuable.

Good, stable homes for Panamint Rattlesnakes are also a limited resource. Such homes usually offer: overwintering chambers lying at manageable angles deep in rock piles, in places sheltered from rain, floods, ice, snow, or exposure to dangerous predators; seasonally warm surfaces that snakes can reach easily from overwintering chambers; and abundant hiding places.

To avoid mating with close relatives, males have to travel between such homes. Enterprising males arrive early enough to maximize chances of meeting a breeding female but not early enough to freeze.

In early spring, at one particular site in my region, rattlesnakes of all ages and sizes emerge from an overwintering slot deep in the rocks and bask together on a stone shelf adjacent to the slot. To leave or return to the basking shelf and the den, most snakes crawl along a narrow corridor to a wider, bitterbrush-shaded ledge — a site I call the veranda. During peak commuting hour, at sunset, snakes may accumulate on the veranda while waiting to crawl single-file back to the den for the night.

The basking shelf can be crowded with juveniles, uninterested females, and even occasional whipsnakes. A would-be paramour can avoid those throngs by waiting on the veranda to meet snakes commuting from the den. Each spring, large male rattlesnakes stack up together like innertubes in bitterbrush on the veranda. Sometimes, they appear when snow patches still dot the ground, before anyone emerges onto the shelf.

Although large male rattlesnakes sometimes gain the basking shelf and spar there while other snakes look on (or flee the fuss), most males accumulate on the veranda, where they rest and spar together among other males doing the same. Most sparring seems to happen there, in the “waiting” zone, often without females present. A male rattlesnake who loses at the veranda or on the basking shelf still has chances to mate; I’ve observed matings off-shelf and off-veranda. But males on the veranda and shelf have higher chances.

That’s not the whole story. Rattlesnakes who reach adulthood might live for decades. They have limited ranges, and they’re likely to encounter the same individual snakes, or at least their scent trails, more than once. Like other long-lived social animals, rattlesnakes can distinguish between other individuals and choose to spend their time in the company of only some.4 In stressful situations, they’re more secure in others’ company.5 They don’t seem to be able to communicate across long distances, but their chemical signals and sensitive sense of smell do allow them to communicate across time to other rattlesnakes who arrive later.6 And thus, when we see solitary rattlesnakes, we don’t see the whole snake, a snake who navigates complex landscapes in difficult weather in anticipation of breeding, hunting, or overwintering. We don’t detect scent signals they leave for others; we don’t know what roles they play in their communities. We witness only fragments of their lives.

Two male Panamint Rattlesnakes (orange rattlesnakes with reddish-brown blotches and bands) engaged in combat. About one-third of their bodies are lifted off the ground, curved, partially entwined, and facing each other. One appears to be pulling the other down.
An earlier view of the snakes in the cover photo. In this view, the female is resting her head on one of the males. (I’m hoping that’s not because she was worried about me. She started out behind the others, then moved forward, and then retreated to her original position soon after.)

Chances to court females are valuable, but not necessarily worth dying for. Past a certain age, a male rattlesnake who loses in combat might have higher cumulative chances of mating success in the future than he does in the present — the sum of all future mating opportunities as an older, wiser, and potentially stronger male versus the chance of mating this year. For a winning Panamint Rattlesnake, incurring a painful or fatal injury that endangers his breeding success right now isn’t worthwhile in the short- or long-term. Sparring offers an honest way to determine which males can remain close to concentrations of females without incurring permanent or fatal injuries.

Panamint Rattlesnakes may also benefit from recognizing others and remembering stronger or more skillful opponents. In a study of captive South American Rattlesnakes, “subordinate males avoided the dominant male throughout the austral autumn” and “were never seen courting captive females.”7 It’s helpful to avoid sparring twice with someone who recently defeated you.

Male rattlesnakes who spar in a way that doesn’t allow cheating but does allow victors and losers to remember each other, avoid injuries, and live to mate again another day are likely more successful rattlesnakes. Gentle sparring makes sense after all.

References

  1. Tetzlaff, S.J., Davis, M.A., Schuett, G.W., Hileman, E.T., Sperry, J.H. and Brown, W.S., 2023. Maladapted in the Anthropocene: communal hyperfidelity in snakes. Frontiers in Ecology and the Environment, 21(6), pp.266-268.
  2. Taylor, E.N. and Booth, W., 2016. Rattlesnakes as models for reproductive studies of vertebrates. Rattlesnakes of Arizona, 2, pp.123-157.
  3. E.g., Greene, H.W., May, P.G., Hardy Sr, D.L., Sciturro, J.M. and Farrell, T.M., 2002. Parental behavior by vipers. Biology of the Vipers, pp.179-205. And: Amarello, M., Smith, J. and Slone, J., 2011. Family values: Maternal care in rattlesnakes is more than mere attendance. Nature Precedings, pp.1-1.
  4. E.g., Amarello, M., 2012. Social Snakes? Non-random association patterns detected in a population of Arizona black rattlesnakes (Crotalus cerberus). Arizona State University. And: Tetzlaff, S.J., Vizentin‐Bugoni, J., Sperry, J.H., Davis, M.A., Clark, R.W., Repp, R.A. and Schuett, G.W., 2023. Fission–fusion dynamics in the social networks of a North American pitviper. Ecology and Evolution, 13(8), p.e10339.
  5. Martin, C.E., Fox, G.A., Putman, B.J. and Hayes, W.K., 2023. Social security: can rattlesnakes reduce acute stress through social buffering? Frontiers in Ethology, 2, p.1181774.
  6. E.g., Muellman, P.J., Da Cunha, O. and Montgomery, C.E., 2018. Crotalus horridus (Timber Rattlesnake) maternal scent trailing by neonates. Northeastern Naturalist, 25(1), pp.50-55.
  7. Batista, S.F., Muniz-Da-Silva, D.F. and Almeida-Santos, S.M., 2021. Dominant and submissive behaviour in the rattlesnake Crotalus durissus under semi-natural conditions. Herpetological Bulletin, 157, pp.21-24.

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