When did animals leave their first footprint on Earth?

Mindy Sparks
June 8, 2018

The tracks were left by a primitive ancestor of modern-day insects or worms, according to scientists.

Recently, an global research team reported discovering fossil footprints for animal appendages in the Ediacaran Period (about 635-541 million years ago) in China.

This remarkable discovery is hailed in a study, published yesterday in the journal Science Advances by a research team from Virginia Tech University in the US and the Nanjing Institute of Geology and Palaeontology (NIGP) of the Chinese Academy of Sciences. The latest prints date to the Ediacaran period, whose sparse fossil record is populated with soft-tissued creatures including worms and organisms that resembled tiny immobile bags.

The trackways were found in the Yangtze Gorges area of South China.

"The rock that contains the fossil has been very well dated between 551 and 541 million years old", Zhe Chen, the study's author and a researcher at the Chinese Academy of Sciences, said in an email.

In other words, this prehistoric critter wasn't a biped like you or me, but perhaps something with multiple paired legs - such as a spider, or a centipede - although given we have so little to go upon, the researchers emphasise it's impossible to know for sure what specific form this early walker embodied. The trackways are somewhat irregular, consisting of two rows of imprints that are arranged in series or repeated groups. That's hundreds of millions of years before dinosaurs started roaming Earth, about 245 million years ago. They are one of the most diverse animal groups in existence today.

While bilaterian animals - including arthropods and annelids - were suspected to have first stretched their innovative legs prior to the Cambrian explosion, in what's called the Ediacaran Period, before now there was no evidence for it in the fossil record.


The identity of the creature that made the 546-million-year-old tracks is still unknown, but they come from the period when the earliest animals are thought to have evolved.

"The characteristics of the trackways indicate that they were produced by bilaterian animals with paired appendages that raised the animal body above the water-sediment interface".

While the researchers are unable to identify the animal behind the footprints, there are three types of living animals with paired appendages: arthropods such as bumble bees, annelids such as bristle worms, and tetrapods which include humans.

"It is important to know when the first appendages appeared, and in what animals, because this can tell us when and how animals began to change the Earth in a particular way."

"Together, these trackways and burrows mark the arrival of a new era characterized by an increasing geobiological footprint of bilaterian animals", the researchers point out.

The trackways appear to be connected to burrows, suggesting that the animals may have periodically dug into sediments, perhaps to mine oxygen and food.

Other reports by Iphone Fresh

Discuss This Article

FOLLOW OUR NEWSPAPER