Sets of footprints found in Denmark and dated to 5,000 years ago are providing insights into what life must have been like among Stone Age coastal peoples living there, archaeologists say.

Two separate sets of footprints were uncovered on Lolland Island in the Baltic Sea during excavations by researchers from the Museum Lolland-Falster.

"This is really quite extraordinary, finding footprints from humans," said museum archaeologist Terje Stafseth. "Normally, what we find is their rubbish in the form of tools and pottery, but here, we suddenly have a completely different type of traces from the past, footprints left by a human being."

Because the two sets were uncovered near the remains of a fishing fence or trap dated from around the same time, it is likely the footprints are those of fishermen, the researchers say.

"What seems to have happened was that at some point they were moving out to the [fish fence], perhaps to recover it before a storm," excavation project manager Lars Ewald Jensen said. "At one of the posts, there are footprints on each side of the post, where someone had been trying to remove it from the sea bottom."

The discovery on the flat terrain of Lolland Island, which was crisscrossed by streams and inlets until a sea dyke was built at the end of the 19th century, is the first of its kind ever made in Denmark, the researchers say.

"We are familiar with animal footprints, but to the best of my knowledge, we have never come across human footprints in Danish Stone Age archaeology before," Stafseth said.

The researchers have been working as quickly as they can to recover artifacts and fossil evidence from the site, which will be lost next year with the beginning of construction of an underwater tunnel linking Denmark with Germany, under the Baltic from Lolland to the German island of Fehmarn.

Above ground facilities on Lolland for the planned Fehmarn Belt Fixed Link tunnel will cover up beds of many dried ancient fjords, including the one in which the footprints have been found.

Museum archaeologists have been busy making molds of the uncovered footprints, preserving them for further study.

In addition to the footprints, the researchers have uncovered a number of skulls of wild and domestic animals, possibly remains from offerings made by farmers living in the area some 4,000 years ago.