Findings: Mice signpost the way home

Wood mice use a "Hansel and Gretel" approach to find their way around while out exploring, according to Oxford University researchers, writes Natasha Gilbert.

David Macdonald and Pavel Stopka of Oxford's department of zoology observed that wood mice distributed visual markers to signpost sites of interest and navigate foraging expeditions.

The researchers had previously noticed that where wood mice had been active in the field there were accumulations of small objects such as leaves, shells and twigs.

They investigated this phenomenon in an experimental enclosure. They replaced the natural visual markers with white discs and used video surveillance to record the mice.

They found that the mice redistributed the white discs to areas of interest to them and then oriented their foraging and exploratory movements to and from the discs. Statistical analysis showed that there was a significant association between the sites at which the mice laid markers and their subsequent pattern of movements.

The mice navigated using the white discs "as if (moving) along the spokes of a wheel with the marker at its hub", the study states.

The researchers suggested that these portable signposts or "way-marks" could help these animals quickly relocate a foraging site after dashing for cover when startled by a potential threat.

The study says that wood mice come up against particularly pressing navigational challenges. These small, nocturnal rodents occupy home ranges with homogeneous landscapes (for example, fields of uniformly planted cereal crops or ploughed fields) that are vast compared with their body size.

Professor Macdonald told The THES that to the best of his knowledge the only other species that used this tactic was Homo sapiens .

The study states: "Humans might place a series of canes in the ground as a reference point from which to search for a set of keys dropped on the lawn."

The findings are published in the online journal BMC Ecology .