Dinosaur Trackways and Footprints: What Ancient Prints Reveal

While dinosaur bones tell us what these animals looked like, dinosaur footprints tell us how they lived. Fossilized trackways—sequences of footprints preserved in ancient mud, sand, or volcanic ash—are some of the most valuable and underappreciated fossils in paleontology. They capture a single moment in time: a living dinosaur walking, running, hunting, or traveling in a herd. Unlike bones, which represent death, footprints represent life in action.

How Dinosaur Footprints Fossilize

Footprint fossilization requires a specific sequence of events:

The Right Surface: The dinosaur walked on soft, moist sediment—mud along a riverbank, wet sand on a beach, or damp volcanic ash. The ground had to be soft enough to take an impression but firm enough to hold its shape.
Drying: The prints hardened as the sediment dried in the sun or air, setting the impression.
Burial: A new layer of sediment (from flooding, wind, or volcanic activity) covered the tracks before erosion could destroy them.
Lithification: Over millions of years, both layers turned to stone, preserving the prints permanently.
Exposure: Erosion eventually removed the upper layer, revealing the prints at the surface.

Some of the finest trackways were made in tidal flats and river margins—environments where wet sediment was regularly covered by new deposits.

What Footprints Tell Us That Bones Cannot

1. Walking Speed and Running Ability

In 1976, British biomechanist R. McNeill Alexander developed a formula that uses stride length and hip height to estimate an animal’s walking or running speed. This formula has been applied to thousands of dinosaur trackways:

Tyrannosaurus Rex: Track evidence suggests typical walking speeds of 5-11 km/h (3-7 mph), with some tracks suggesting faster movement up to 25-30 km/h
Ornithomimids: Some of the fastest trackways ever recorded, with estimated speeds of 40-50 km/h (25-31 mph)
Sauropods: Lumbering giants like Brachiosaurus walked at a leisurely 5-7 km/h (3-4 mph), about the pace of a human stroll

Trackways provide the strongest evidence for dinosaur social behavior:

Parallel Trackways: Multiple trackways of the same species heading in the same direction at the same pace strongly suggest herding behavior. Sites in Texas, Colorado, and Australia show dozens of sauropod tracks moving together.
Size Sorting: Some trackway sites show large adults on the outside and smaller juveniles in the center of the group—evidence of protective herding behavior identical to modern elephants and muskoxen.
Theropod Packs?: A controversial trackway site in China shows three large tyrannosaur-type prints walking in parallel, fueling the debate about whether large predators hunted in groups.

3. Hunting Behavior

A handful of extraordinary trackway sites capture predator-prey interactions frozen in stone:

The Glen Rose Trackway (Texas): A famous site showing the footprints of a large theropod following the tracks of a sauropod. The predator’s tracks converge with the herbivore’s, suggesting an active pursuit or stalking event.
Attack Traces: Some rare sites show tracks that suddenly change direction, become deeper (indicating acceleration), or show signs of stumbling—evidence of a chase in progress.

4. Posture and Gait

Footprints settled a major scientific debate about dinosaur posture:

Upright Walking: Dinosaur tracks show feet placed directly beneath the body (narrow trackway), confirming that dinosaurs walked upright with legs positioned under the body—not with a sprawling, lizard-like gait.
Tail Position: The near-total absence of tail drag marks in dinosaur trackways proved that dinosaurs held their tails off the ground, not dragging behind them as depicted in early 20th-century art.
Bipedal vs. Quadrupedal: For species like Iguanodon, trackways show both two-legged and four-legged prints, confirming these animals switched gaits depending on activity.

5. Swimming Evidence

Some remarkable trackways show only the tips of front claws scraping the bottom of a shallow waterway, with no hind-foot prints visible. This suggests the dinosaur was floating in water, using its front limbs to paddle or push off the bottom—direct evidence of swimming behavior.

Famous Trackway Sites Around the World

Dinosaur Ridge (Colorado, USA)

Age: Late Jurassic to Early Cretaceous
Highlights: Over 300 dinosaur footprints visible along an exposed rock face, including large sauropod and theropod tracks
Access: Open to the public as a National Natural Landmark

Cal Orcko (Sucre, Bolivia)

Age: Late Cretaceous (~68 million years ago)
Highlights: The largest known dinosaur trackway site in the world—a massive limestone cliff face containing over 5,000 individual footprints from at least 8 different species spanning a 25,000-square-meter surface
Unique Feature: The tracks are on a near-vertical cliff face, originally a flat lake shore that was tilted by tectonic activity

Lark Quarry (Queensland, Australia)

Age: Mid-Cretaceous (~95 million years ago)
Highlights: Over 3,300 footprints interpreted as a dinosaur stampede—dozens of small dinosaurs fleeing from a large predator
Debate: Some scientists now question whether this was truly a stampede or simply a busy crossing point

Paluxy River (Glen Rose, Texas, USA)

Age: Early Cretaceous (~113 million years ago)
Highlights: Famous sauropod tracks alongside theropod tracks—interpreted as a predator stalking prey
Historical Note: This site was also the source of the infamous “man tracks” hoax—depressions that were falsely claimed to be human footprints alongside dinosaur tracks

Isle of Skye (Scotland)

Age: Middle Jurassic (~170 million years ago)
Highlights: Sauropod trackways preserved in lagoon sediments, providing rare evidence of Jurassic dinosaurs in what is now northern Europe

Types of Dinosaur Footprints

Theropod Tracks (Meat-Eaters)

Shape: Three-toed with sharp claw marks
Pattern: Narrow trackway (feet placed close to the midline)
Features: Deep toe impressions, sometimes with a visible dew claw (the small fourth toe)
Example Species: Allosaurus, T-Rex, Velociraptor

Sauropod Tracks (Long-Necked Giants)

Shape: Massive, rounded (hind feet) with smaller crescent-shaped front feet
Pattern: Wide trackway (wide gauge between left and right feet)
Features: Some of the largest footprints ever found—up to 1.7 meters (5.5 feet) in length
Example Species: Brachiosaurus, Argentinosaurus

Ornithopod Tracks (Duck-Bills and Relatives)

Shape: Three-toed but broader and rounder than theropod tracks, without sharp claw marks
Pattern: Medium-width trackway
Features: Often show skin texture impressions on the sole of the foot
Example Species: Iguanodon, Edmontosaurus

Ceratopsian Tracks

Shape: Four- to five-toed front feet, three-toed hind feet
Pattern: Wide gauge
Features: Relatively rare in the fossil record
Example Species: Triceratops

Trace Fossil Science: Ichnology

The study of trace fossils (including footprints) is called ichnology, and it has its own naming system. Footprint types are given ichnospecies names—separate from the names of the animals that made them:

Grallator: Small three-toed theropod tracks (likely made by coelophysids)
Eubrontes: Large three-toed theropod tracks
Brontopodus: Large sauropod tracks
Anomoepus: Small ornithischian tracks, sometimes showing sitting impressions

This separate naming system exists because it’s often impossible to determine exactly which species made a particular footprint—we can only identify the general type of animal.

Record-Breaking Dinosaur Tracks

Largest Single Footprint: A sauropod track from Australia measuring 1.75 meters (5.7 feet) in length—large enough for an adult human to lie down inside
Longest Continuous Trackway: A sauropod trackway in Portugal stretching over 147 meters (482 feet)
Most Tracks at One Site: Cal Orcko, Bolivia, with over 5,000 individual prints
Highest Altitude Tracks: Dinosaur footprints found at over 4,500 meters (14,760 feet) in the Himalayas—originally formed at sea level but lifted by tectonic forces

Frequently Asked Questions

Q: How can you tell the difference between a theropod and ornithopod footprint? A: Theropod (meat-eater) tracks are typically narrower with sharp, defined claw marks. Ornithopod (plant-eater) tracks are broader, rounder, and lack sharp claw impressions. The trackway width (distance between left and right prints) also differs.

Q: Can footprints tell us what color dinosaurs were? A: No, footprints cannot reveal color. However, they can sometimes preserve skin texture impressions, showing the pattern of scales on the sole of the foot.

Q: Why don’t we find dinosaur footprints everywhere? A: Footprint preservation requires very specific conditions—the right sediment moisture, rapid burial, and millions of years of undisturbed lithification. Most footprints were simply washed away or eroded within days of being made.

Q: Can we tell if a dinosaur was injured from its footprints? A: Sometimes, yes. Trackways occasionally show limping patterns (uneven stride lengths or depth differences between left and right feet), suggesting the animal was favoring an injured limb.

Dinosaur trackways are paleontology’s equivalent of security camera footage—brief, tantalizing glimpses of living animals going about their daily lives millions of years ago. Every new trackway site discovered adds another frame to the incredible movie of prehistoric life on Earth.