Summary: Airoldi, J.-P. & de Werra, D. (1993). The burrow system fo the fossorial form of the water vole
(Arvicola terrestris scherman Shaw)(Mammalia, Rodentia): an approach using graph theoretical
methods and simulation models. Mammalia 57 (3) : 423-433.
41 burrow systems of the fossorial form of the water vole (Arvicola terrestris scherman Shaw.), a
small rodent inhabiting meadows, pastures and orchards in central Europe, have been analyzed
using methods of graph theory. Four main types exist: a) linear structure (trees), b) trees with a
few cycles, c) mixture of linear and cyclic structures, d) essentially cyclic structures. The
intersections with 3 branches clearly predominate (97 %). The length of the edges (segments
joining a dead-end and an intersection or two intersections) follow an exponential distribution
with a mean and a standard deviation being usually very close. The nest is generally closer to a
central point (i.e. a point closest to any intersection or dead-end) than would be expected by
chance. The connections between any two intersections or an intersection and a dead-end can be
summarized in the form of an adjacency matrix; a method of reducing its size by eliminating the
trees connected to the cyclic part was used when computing the shortest paths, in order to save
computing time and space.
Two simulation models are briefly described. The first one is rather simple and produces planar
graphs with straight edges. The second one is more elaborate, has more parameters and
approximates real burrow systems quite well; it also allows to take into account areas of
favorable and unfavorable environment and the behavior of voles accordingly.