Around 30,000 species of land animals - including human beings - may have descended from a common ancestor that had a well-developed sixth sense, according to a new study.
The common ancestor is believed to be an aquatic vertebrate, probably a predatory fish, which had good eyesight, jaws and teeth and also a lateral line system used for detecting movement in the water.
Living around 500 million years ago, the fish is thought to be a common ancestor of the majority of the 65,000 living vertebrate creatures, according to researchers.
"This study caps questions in developmental and evolutionary biology, popularly called 'evo-devo', that I've been interested in for 35 years," said Willy Bemis, Cornell professor of ecology and evolutionary biology at the University of Cambridge and a senior author of the paper.
The study, which appears in the latest edition of Nature Communications, marks the end of 25 years of work into the subject.
Some land vertebrates, including salamanders like the Mexican axoloti and ray-finned fish such as paddlefish and sturgeon, still retain this electrosense ability.
But adaptation to terrestrial life meant reptiles, birds and mammals lost electrosense.
Professor Bernis and his team found that the electrosensors of the ray-finned fish and the salamander developed in precisely the same pattern from the same embryonic tissue in the developing skin, confirming that this is an ancient sensory system.