In Argentina, one type of mistletoe (Tristerix corymbosus) depends on this nocturnal, squirrel-sized, silken-coated creature to disperse its seeds. D. australis eats the sticky fruits of the parasitic mistletoe and defecates 98 per cent of the seeds intact on to the trunks of other shrubs, where they take hold and germinate.
This task was previously thought to be "carried out exclusively by birds", researchers Guillermo Amico and Marcelo A. Aizen report.
98% of the mistletoe seeds are defecated intact
In fact, the marsupial's ancestors may have been doing the same thing for the past 70 million years.
"Our findings suggest that marsupial dispersal of mistletoe seeds might represent a very primitive mutualism", the researchers from the Universidad Nacional del Comahue, Río Negro, Argentina say.
Such relationships may have been more widespread along the tropical Andes in the past, they believe.