The First Documented Male-Male Combat in Black-banded Snakes! - Observation of the Week, 9/28/20

Our Observation of the Week is this pair of Black-banded snakes (serpiente come ciempiés - Scolecophis atrocinctus), seen in Costa Rica by @elainechernov!

Elaine Chernov, a designer from the Los Angeles area, and herpetologists Erich P Hofmann (@ephofmann, based in North Carolina, US) and Wolfgang Wüster (@wolfgang_wuster, based in the UK) recently published a Natural History Note in Herpetological Review [PDF] about this observation, which is likely the first documented instance of male-male combat in this species! But according to Elaine, someone else also deserves credit: “My 6 year-old son, Miles, actually deserves some credit. He saw the snakes first!”

Elaine and her two children spend a good amount of time in Costa Rica, as her parents have retired there. “I try to get out into all the beautiful preserved land they have there as much as I can,” she says.

Rincón de la Vieja is the closest volcanic national park to my family's house, so my son and I went for a day trip to hike up to a beautiful waterfall to start off the new year. He was such a trooper—we hiked for 4 hours, and on the way back he spotted these snakes on the ground. I thought maybe they were mating, so I loudly proclaimed, "Aww they are hugging!" to him hoping for limited questions about what they might be doing.

So, she posted the snakes to iNaturalist. Erich P Hofmann, currently a biology instructor at Cape Fear Community College in North Carolina, tells me he has taxon subscriptions “set up for several cryptic, fossorial/semi-fossorial snake species I’m particularly interested in and/or have conducted research on, including Scolecophis and Homoroselaps.” Because these snakes are so small and are often hiding under the leaf litter, they are not often seen (as of now, only thirty-four have been observed on iNat) and “because they are rarely encountered, very little is known about their natural history, and behavioral data is especially lacking.”

Elaine’s observation, then, was intriguing, and soon Erich and Wolfgang (who is based in the UK) began discussing it, as well as sharing it on Facebook. Other herpetologists such as Harry Greene and Gordon Schuett weighed in and suggested it was worth publishing. “Elaine was keen to collaborate on publishing the observation” says Erich, “and she shared with us additional photos and a video of the snakes that she took, which was a phenomenal additional piece–not only an incredibly lucky observation of a rare snake species engaged in a potentially unreported behavior, but one with video that could be further examined!”

Both Erich and Wolfgang tell me that male-male combat is pretty well known among larger snakes such as rattlesnakes and other vipers, as well as long-bodied colubrids like those in the genus Pituophis. Erich explains,

[it’s] generally a kind of wrestling match: in larger-bodied taxa like rattlesnakes (Crotalus), combat consists of two posturing snakes moving and entwining their bodies, raising their heads and anterior trunks, and repeatedly attempting to “pin” the head and neck of the other snake until eventually one concedes. Similarly, in smaller-bodied snakes like coral snakes (Micrurus), two snakes intertwine their bodies, sometimes rolling and spinning around, and again try to gain dominance over their opponent by moving their head and neck above their opponent’s head and neck. However, the lifting of the head and anterior trunk isn’t seen–as we understand it, combat takes place mostly horizontally in smaller snakes. Biting appears to be rare in either case; it is really more of a physical match.

After doing some research, Erich and Wolfgang only found two examples of small colubrid snakes (in the genus Sonora) engaging in male-male combat, so it’s not common, or at least not commonly observed, in small snakes. Elaine’s observation was the first known documentation of such behavior in this species, although the two herpetologists note that because the snakes were not sexed, there’s a possibility the snakes were two different sexes. But in all likelihood both snakes are male, as the behavior hews closely to other documented male-male combat. “It was a really great example of citizen science and social media connecting observations and those able to make the most of them, and adding a little brick to the edifice of our knowledge of the natural world,” says Wolfgang.

Elaine (above, with her children) tells me she shared and discussed her notes, photos, and video with Erich and Wolfgang, then “walked around gloating about being a published scientist to anyone that would listen.” She uses iNaturalist to learn about what she sees, and she’s also helping her daughter (who’s now “obsessed with bugs”) ID her finds. “I'm a single mom with two very young kids and...love using the app to be able to tell them what the thing we saw while out on a hike was called,” she says.

Wolfgang, a snake expert, has contributed nearly 37,000 IDs to iNaturalist, and says he likes using it for several reasons: coming across new locations for the species he studies, honing his ID skills (“with a whole bunch of other highly experienced naturalists on the platform, you are kept on your toes, and you soon relearn humility when you screw up!”), data for niche modeling and just as a social platform.“There are some incredibly knowledgeable and talented people on iNaturalist that don't otherwise use social media,” he says,  

and that I would not have come to interact with without this platform. And also, it's a great bastion of positivity in a social media landscape dominated by politics, news (usually depressing) and discord - we are all here for the same reason, brought together by what unites us rather than by what divides us. That is something to be treasured in these fractious times...While I would advocate a little bit of extra care in managing potential impacts on sensitive species, the overall balance sheet is very much positive!

For his part, Erich notes that platforms like iNat can bring together people from around the world, as the people participating here hail from “California, North Carolina, and the UK, and the observation took place in Costa Rica!

There have been many iNaturalist observations that have ended up published as natural history notes or used in datasets for larger papers, but even seemingly “normal” observations of everyday taxa help to clarify our understanding of the natural world. Many people now have cameras in their pockets, and take pictures just to learn more about a plant or animal; by sharing them to platforms like iNaturalist, these simple pictures can be seen by experts, and may spark discussions, give rise to new hypotheses, or lay the foundation for future studies. Natural history is the foundation of good scientific inquiry in biology, and the collection of natural history data used to be restricted essentially only to scientists in the field. Now, citizen/community scientists are adding important new pieces to the overall puzzle of biodiversity and natural history of organisms on Earth simply by taking photos of things they encounter, and wanting to learn more about them. It all starts with the observers, and I’m very happy that Elaine shared her photo on iNaturalist and was open and excited about publishing the observation!

- Herpetologist @gregpauly noted that the black-banded snake publication “is 1 of 8 that reference iNaturalist observations in this issue of Herpetological Review. Plus, one book review and one research summary also mention iNaturalist. So, 10 different articles referencing iNaturalist in one journal issue!” You can download it by section at https://ssarherps.org/herpetological-review-pdfs/

- Here’s some footage of king cobra males engaging in combat. 

Posted on September 29, 2020 12:11 AM by tiwane