Using an alternative tracking technique, Brazilian researchers managed to describe the shelters and movement paths of several forest rodent species for the very first time. With the help of spool-and-line, they also revealed a number of interesting behaviors.
By Arielli Machado
Neotropical rainforests accommodate a number of coexisting small mammal species. Knowledge about the animals’ movements and use of space, however, remains scarce. A group of biologists from the Federal University of Santa Maria in Brazil set themselves the task of finding out more about the lives of forest rodents – where do they find shelter? How do they move? What environmental structures do they use?
The focus species of their study, recently presented in Mammalia, was Akodon montensis, also known as the montane grass mouse, a common rodent from the forests of southern Brazil. The researchers also briefly described other common rodents in the area, such as Thaptomys nigrita (the “blackish grass mouse”), Brucepattersonius iheringi (“Ihering’s akodont”) and Oligoryzomys nigripes (the “black-footed pygmy rice rat”). The study took place in one of the largest natural parks in southern Brazil, Turvo State Park, where the second widest longitudinal waterfall in the world can be visited as an ecological tourist attraction.
A simple but effective tracking technique
To track the local rodents’ movements and use of space, the researchers made use of the spool-and-line technique, which involves the attachment of line bobbin devices to the bodies of trapped individuals. As the released animals move, the spools unwind, thus marking the paths they traverse.
With the help of this tool, the researchers were able to describe the shelters and potential nests of the montane grass mouse for the first time. They found that shelters ranged from smaller structures with only one entrance to larger and more elaborate structures with several entrances. According to the researchers, multiple entrances may indicate nest sharing among individuals of the species. They also found that some individuals liked to climb on fern trunks.
They furthermore showed that species such as the blackish grass mouse and Ihering’s akodont, which are adapted to digging and (sometimes) living underground, are able to travel long distances under dense layers of fallen leaves, as well as under fallen logs and fern trunks.
The black-footed pygmy rice rat mostly moved above ground, climbing on fallen logs, lianas, bamboos and on the shrub Piper aduncum (also known as “spiked pepper”), which rodents often feed on.
According to the researchers, “the study takes the first step towards understanding the movements of these wild rodents and the way they use environmental structures.”
Read the original article here:
Arielli F. Machado, Cristiane F. Marks, Brisa Peres, Geruza L. Melo and Nilton C. Cáceres: Movement and use of environmental structures, climbing supports and shelters by Akodon montensis (Sigmodontinae, Rodentia) in the Atlantic Forest of southern Brazil, 27.03.2019.