Key takeaways
- Made on flat ground and tilted towards vertical by the folding that raised the Andes.
- Laid down before the extinction that ended the age of the large dinosaurs.
- The afternoon of the tour is spent here rather than glanced at in passing.
- The famous wall on the edge of Sucre is a different site, and this tour does not go there.
What a footprint has to survive
A track is a hole in mud, and almost every one ever made is gone. To become a fossil it needs a very specific run of luck: ground soft enough to take an impression and firm enough to hold it, then no rain to wash it out, then a covering layer of sediment gentle enough not to destroy it, and then tens of millions of years without the rock being crushed, melted or dissolved.
The odds against any single print are enormous, which is why trackways are rare and why a site with a great many of them is worth travelling for.
The conditions here were a lake or river margin: flat, wet, fine-grained, periodically flooded. Almost the ideal recipe.
It is worth being clear about what a track is and is not. A footprint is not a fossil of an animal; it is a fossil of a moment, which is a rarer and in some ways more informative thing. Bones tell you what an animal was built like. Tracks tell you where it went, how fast, and whether it was alone.
Why they are vertical
This is the part that makes the site remarkable, and it has nothing to do with the dinosaurs. Animals do not walk on walls.
The surface was horizontal when the tracks were made. It was buried, hardened into rock, and then, tens of millions of years later, caught up in the folding that raised the Andes and pushed the whole bed round towards the vertical.
So the tracks are exactly where they were left. It is the ground that moved, and it moved as part of a mountain range. Standing in front of them you are looking at a piece of evidence that the rock was once flat, which is the clearest demonstration of the geology anywhere in the crater.
A line of prints running up a near-vertical bed of rock
What made them
Identification is done from shape, size, spacing and depth rather than from bones, and the animal is described by the track rather than named by species. A three-toed print of a certain size and stride is one kind of animal; a broad rounded print with a shorter stride is another.
The Cretaceous of this part of South America carried both large plant-eating sauropods and bipedal theropods, and prints of both kinds are known from the region.
Ask the guide what is in front of you rather than assuming. Trackways vary across a site and the interesting question is not which dinosaur but what it was doing: walking, running, turning, or moving in a group.
The other thing a trackway records is behaviour, which no skeleton can. Several sets of prints running parallel in the same direction suggest animals moving together. A stride that lengthens suggests one that began to run. A turn suggests something that changed its mind. None of that is recoverable from bones, and all of it is sitting in a wall.
How the site compares with Cal Orcko
Cal Orcko, on the edge of Sucre, is the famous one: an enormous near-vertical wall in a working cement quarry carrying thousands of prints, with a visitor centre and a viewing platform.
This tour does not go there. If Cal Orcko is what you want, it is a short trip from the city and a separate booking.
The Maragua tracks are quieter, smaller, less managed, and set in the landscape that explains them. At Cal Orcko you look at a wall in a quarry. Here you look at a wall inside the structure that tilted it, having walked in over the same rock.
2 h
Time the tour spends at the footprints. It is the afternoon of the day rather than a stop on the way past, which is what a site like this needs.
What two hours actually buys you
Time. The tour allows about two hours at the footprints, which is far more than a photo stop, and it is the right amount for a site that rewards being looked at rather than glanced at.
It gives the guide room to explain the sequence properly, to point out prints you would walk past, and to answer the questions that only occur once you have been standing there for twenty minutes.
It also means the afternoon is not rushed, which given the walking in the morning is a sensible way to build the day.
It also allows for the thing that most tour itineraries squeeze out, which is standing still. A trackway is not a view: it does not resolve at a glance and it does not photograph well in a hurry. Twenty minutes in, prints start appearing that were invisible for the first ten, and that is the point at which most people stop taking pictures and start looking.
Looking after them
Trackways erode. The same water and weather that exposed a surface will eventually destroy it, and prints in soft rock at altitude have a limited life once they are uncovered.
Do what the guide says about approaching and touching. It is not fussiness: the oils and the abrasion from hands genuinely accelerate the damage, and a site that has survived a hundred million years can be worn out by visitors in a few decades.
Photograph rather than touch, and stay on the ground you are shown.
Photographing tracks
Low, raking light is what makes a print readable, because it is depth rather than colour you are trying to record. Overhead midday sun flattens a trackway into an unremarkable surface.
If the light is flat, use something for scale: a hand, a boot, a hat placed beside a print. Without a reference nobody looking at the photograph afterwards can tell whether they are seeing something the size of a saucer or the size of a bathtub.
And photograph the wall as well as the prints. The context, a vertical bed in a folded landscape, is half of what makes the site extraordinary.
