Explainer

Why Can't Washington Find More Dinosaur Fossils?

A decade ago, the state dug up a fragment of the "Suciasaurus." It hasn't found any remains since.

By Taylor McKenzie Gerlach September 20, 2022 Published in the Fall 2022 issue of Seattle Met

The Suciasaurus femur fragment.

It looked like any other shoreline rock at Sucia Island Marine State Park. But to the trained eye of Burke Museum research associates one afternoon in 2012, it was a groundbreaking discovery: Washington’s first dinosaur fossil.

The femur fragment of a tyrannosaur remains the state’s one-bone wonder. Among giant ferns and mammoth moss-covered trees straight off the set of Jurassic Park, traces of our planet’s giant prehistoric creatures have continued to avoid detection.


Suciasaurus graphic with femur fragment.

The estimated length of the "Suciasaurus" is 37 feet. The fossil discovered in Washington, the fragment depicted within the hip bone here, is 17 inches.

The “Suciasaurus”

On the shore of Sucia Island, a tiny arc of land in the north San Juans, researchers unearthed the fragment of a left thigh bone. It belonged to a theropod dinosaur—a two-legged, three-toed, carnivorous creature related to the Velociraptor, Tyrannosaurus rex, and modern birds. Two calling cards prove this fossil, nicknamed “Suciasaurus,” is unlike the typical marine creature finds in the area: the hollow interior of the bone and the placement of a surface ridge consistent with other theropods.

Sucia Island on a map with the Suciasaurus femur fragment.

Sucia Island (inset), in the north San Juans, is where the fragment of a left thigh bone (lower left) was found.

A Drought Born from the Sea

Between 240 and 66 million years ago, when dinosaurs roamed the earth, Washington was largely underwater.

Water, Logged

The western portion of the state sits on marine rock ripe with fossil ammonites—spiral-shelled sea creatures that lived at the same time as dinosaurs.

Buried Legislation

A campaign to make the Suciasaurus our state dinosaur has stalled in multiple legislative sessions.


Icons from left: Caputo (2) and Lufti Gani Al Achmad (1) / noun project (icons)

For Further Excavation

Experts agree that the land-roaming Suciasaurus never lived here. But they differ on the fossil’s origins. It may have traveled (dead creatures “bloat and float” to new locales far from where they once roved) to Washington from as far away as Baja California, Mexico. Yet more conservative estimates peg the 80-million-year-old bone as our first California transplant. One thing’s for certain: It was a long trip. Shifting tectonic plates delivered the rocks (the Cedar District Formation of rock spans from northwest Washington into Canada) that form modern-day Sucia Island over the course of several million years.

Visitors watch paleontologists prepare fossils during the grand opening of the new Burke Museum in October 2019.

Visitors watch paleontologists prepare fossils during the grand opening of the new Burke Museum in October 2019.

Chipping Away

Since the auspicious discovery in 2012, paleontologists have yet to find any other dinosaur evidence in the state. But they can unearth imported discoveries. At Seattle’s Burke Museum, paleontologists excavate fossils brought to the lab from nearby hot spots like Montana’s Hell Creek Formation. Visitors watch through wide glass laboratory windows as experts carefully pick away at surrounding rock, employing different tools of the trade:

Diamond bladed rock saw: Researchers used this handheld saw to cut the Sucia Island fossil from the rocky beach. 

Air scribe: A mini jackhammer of sorts is the most common tool used in a fossil lab to remove surrounding rock.

Rex rack: Unique to the Burke Museum, this contraption suspends large fossils above the ground for 360-degree rock removal.

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