As amazing as it seems, we have footprints of sauropods on nearly every continent, left during their 140-million-year stint on Earth. And those footprints, many in long trackways, provide some of the best data on the animals' daily life. With them, scientists can tackle such questions as: How fast could these animals walk? Did they travel in groups? Did young and old move together?
Experts use footprints to estimate speed by measuring the length of a stride, which is the distance between two consecutive prints of the same foot. Of course, stride length is a product of leg length as well as speed. By combining evidence from trackways with estimates of leg length, experts have concluded that sauropods might have moved at the pace of a slow human jogger.
Trackways suggest that some sauropods--possibly including Mamenchisaurus--traveled in small, mixed-age groups. Footprints can't be assigned to species, so it's hard to know for sure.
Scientists recently uncovered over 40 sets of dinosaur trackways in a British limestone quarry; one set can be seen in this photo. These trackways, one nearly 650 feet (200 meters) long, seem to record a single event: a large group of dinosaurs moving in the same direction across a mudflat. The group included both adults and juveniles traveling together. Two different types of sauropods, as well as a two-legged meat-eating dinosaur, are represented.