The underground system of Clyomys laticeps changes in structure and composition according to climatic and vegetation variations

Abstract

Ecological factors may affect resource availability and distribution, impacting foraging and burrow construction behaviours. Clyomys laticeps is a caviomorph rodent with subterranean habits occurring on the Brazilian Cerrado domain (savanna-like) until the Paraguayan Chaco. We investigated their underground system’s architecture taking into account the vegetation and climate. We hypothesised that the sparse food distribution in the winter would promote longer tunnels and more complex architectures to connect more distant foraging areas, supposing that the species moved underground to avoid predators; moreover, the winter would promote food storage. We excavated eleven Clyomys underground systems and measured their size and internal parameters (tunnel and chamber width, length and depth) and complexity (linearity and convolution). We noticed that half of the systems were in the open landscape (OL) and half on vegetation covered (VL). If the anti-predation theory was right, we would find shorter tunnels on the VL systems. We found systems from 2 to 24 m² and up to 22 m long. The deeper and biomass scarcer tunnels were on VL during the dry season, supposedly when animals would need underground water but not stocked food (the palm season). Also, they were more complex (higher circularity and convolution indexes) in OL, favouring our anti-predation hypothesis. Furthermore, Clyomys burrows offer refuge for other species such as arthropods, snakes, amphibians, and birds. We conclude that systems’ architecture is related to vegetation presence and seasonal foraging challenges. This rodent may construct its systems for shelter, food storage and as a safe trail among foraging areas.