Though human beings don't have sixth sense and work with only five senses, the most desired sixth sense was present in our fish-like ancestors who lived 500 million years ago.

A study by researchers at the University of Cambridge and Cornell University, NY, suggests that about 30,000 species of land animals -- including humans-- descended from a common marine ancestor that had a well-developed electroreceptive system.

Sharks, paddlefishes and certain other aquatic vertebrates with another sense can detect weak electrical fields in the water and use this information to detect prey, communicate and orient themselves.

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 and a senior author of the study published in journal Nature Communication.

The crucial pieces came from techniques of developmental and molecular biology. Such a synthesis of modern techniques, classical questions and basic anatomy is the cornerstone of 'evo-devo' research, and it promises to help us better understand the origin and evolution of many organ systems, including the brain, Bemis added.

Some land vertebrates, including such salamanders as the Mexican axolotl, have electroreception and, until now, offered the best-studied model for early development of this sensory system.

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