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number five
Nautiloid Canyon
River Mile 35

On the Hunt for Giant Snails

We’re hunting giant snails.

Well, for remnants of them, anyway.

Nautiloid Canyon is so named for the large, snail-like nautiloids that lived here about 400 million years ago. Their fossils are embedded in the limestone of this canyon, but first we have to find them.

Jordy Margid, lead guide and director of UC Davis Campus Recreation and Unions’ Outdoor Adventures program, throws a rope up a cliff and scrambles to the top to secure it for the rest of us. We use it as a “rail” as we hike up a narrow ridge to the top of the trailhead, which overlooks our camp and the Colorado River.

A man dressed in a dress shirt and bowtie plays the a ukelele on the shores of the Colorado River
Ever-dapper river guide and UC Davis lab technician Kyle Phillips plays ukulele mid-hike to Nautiloid Canyon. Credit: Kat Kerlin/UC Davis

I’m still getting my footing here. But Kyle Phillips, a guide and Center for Watershed Sciences lab technician, leisurely walks up this same ridge while strumming a ukulele. He’s wearing black dress pants, a white dress shirt rolled up at the sleeves, piano-key suspenders and a bowtie. Along with a sly smile, he wears a bow tie every day, in every circumstance, whether rowing the boat, swimming or prepping for dinner. It’s just his thing.

Nautiloid scavenger hunt

Further into the canyon, class instructor Sarah Yarnell takes her bottle of water and splashes it over the ground.

“Wow, nautiloids!” says marine ecology graduate student Erin Satterthwaite.

The water reveals the outline of a nautiloid shell, a relative of the modern chambered nautilus.

A fossil of a Nautiloid
A splash of water brings a nautiloid fossil to light in Nautiloid Canyon. Photo: Joe Proudman/UC Davis

The fossil looks more like a caterpillar to me. It’s cylindrical, about 1-2 feet long, with segmented grooves along it. Sarah explains that nautiloids had a squid-like head and snail-like shell. The fossil’s shape likely came from the nautiloid sitting vertically on its end.

“Maybe we should see who can find the biggest one,” Sarah says.

It doesn’t take long before the whole class is heads down and splashing water over the ground in search of more nautiloids and other fossils.

Find of the century

Nautiloids aren’t the only interesting thing in the canyon for this group. Plant sciences professor Truman Young stops along the trail to admire a century plant, a type of agave, its dramatic leaves spiking outward and upward.

It reproduces once in its life and then dies. Why would it do that? Truman later explores the question with the group.

Several students — fire ecologists, geophysicists — wonder if it’s the “suicide theory,” where the plant uses all its resources to make the best babies possible.

But Truman steers them back. It turns out, century plants “cash in” when they think they’re going to die soon anyway, “like people would do in cashing in on their investments toward the end of their lives,” he says.

Erin Satterthwaite, marine ecology grad student, explains what a nautiloid is during a hike in Nautiloid Canyon. Credit: Joe Proudman/UC Davis
This tool of yelling a word is a great way to wrangle the group together for all the important stuff: “Coffee!” “Breakfast!” “Lunch!” “Dinner!” and, of course, “Science!”

Swallowing flies and tamarisk


The camp rings out with the word we hear every evening before dinner. It means, “Hey everybody, stop doing what you’re doing and come sit around in a circle here for some science discussion.”

This tool of yelling a word is a great way to wrangle the group together at camp for all the important stuff: “Coffee!” “Breakfast!” “Lunch!” “Dinner!” and, of course, “Science!”

Each evening at “Science,” one or two students present a talk in their field related to what we’ve seen on this trip. Then we all discuss it and provide feedback about how well the student got the message across.

Evan Wolf, ecology grad student, is on the trail of a tamarisk-eating beaver. Credit: Evan Wolf/UC Davis

The group sits down for “Science!” — a nightly discussion and presentation about what they saw that day as guides prep for dinner. Credit: Joe Proudman/UC Davis

Tonight, it’s ecology graduate student Evan Wolf’s turn.

In this sea of geologists, while everyone is looking at rocks, he’s usually bent over a plant or spotting wildlife. While I saw only a few birds and lizards, leave it to Evan to find bighorn sheep scat, the skeleton of a ring-tailed cat and beaver tracks. Oh, and the beaver tracks? He found those after he noticed where a beaver had been chewing on a tamarisk plant.

Tamarisk takes center stage for his talk. The plant is a well-known, nonnative invasive in the desert Southwest. It’s been in the Grand Canyon since 1938. The science on it is a bit divided. It’s detested by many as a water-sucking, light-hoarding, nutrient-stealing menace. But Evan, a wetlands ecologist, makes us consider its place. He begins with a song:

“I know an old lady who swallowed a fly. I don’t know why she swallowed a fly. Perhaps she’ll die…”

If you know the song, then you know the old lady then swallows a spider to catch the fly. And down the inane food chain the song goes.

All of this is a setup to talk about tamarisk and the tamarisk beetle, another nonnative species that has made its way into the canyon after being introduced in neighboring states to eat tamarisk.

We walk as a group to look at some tamarisk beside the river. Evan points out how native species, like that beaver and some insects, are using the tamarisk.

Does it make sense to introduce one nonnative to wipe out another when there isn’t solid scientific data that tamarisk is displacing native species in the Grand Canyon? Perhaps a better management tactic, Evan explains, is to proactively establish native plants in areas affected by tamarisk rather than reactively try to destroy them.  After all, the conditions for some of those native species to survive are now gone.

“Restore the process, not the outcome,” Sarah says in summary.

The Grand Canyon around us serves as a constant reminder of a world in flux, where a desert was once the sea, and lizards crawl over the fossils of giant sea snails. What can and cannot live here is ever changing.


- Kat Kerlin

grey arrow Continue the journey at Stop 6, Nankoweap Granaries

Trevor Waldien checks out a 400-million-year-old ocean deposit of chert and limestone in the Grand Canyon. Credit: Joe Proudman / UC Davis
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Next Stop...Nankoweap Granaries