A food once eaten by long-extinct dinosaurs, European woodmouse has a unique taste for ferns, scientists have determined.

The mouse regularly devours the spores of the endemic European fern Culcita macrocarpa, the only small mammal known to do so, said a report by BBC News.

Due to the toxic chemical defences often contained within them, it is rare for modern vertebrates to eat ferns.

Dinosaurs used to eat them in bulk and these ancient plants were a favourite of huge sauropod.

Ferns are thought to have played an important role in the diet of dinosaurs, particularly huge sauropods such as Diplodocus, the longest dinosaur known from a complete skeleton.

After noticing bite marks on fertile leaves of the rare fern C. macrocarpa, the only endemic member of a family of ferns called Dicksoniaceae in Europe, an international team of researchers led by Ms Marisa Arosa of the University of Coimbra in Portugal became suspicious.

The researchers studied a set of fern plants, noting how their leaves and spores were removed, and then placed cotton under the plants to collect the droppings of any animal feeding on them.

 Analysis of the droppings revealed them to have been left by the European woodmouse and that they contained the fern spores.

 Aiding the plant’s reproduction, though most spores has been digested,  it may be that the mouse helps disperse them.

 According to the researchers, fern spores are rich in calories, lipids and proteins, providing a vital source of energy to woodmice in winter. (With Input from Agencies)