Postnatal development of subterranean habits in tuco-tucos Ctenomys talarum (Rodentia, Caviomorpha, Ctenomyidae)

ECHEVERRÍA, ALEJANDRA; BIONDI, LAURA MARINA; BECERRA, FEDERICO; VASSALLO, ALDO IVÁN

JOURNAL OF ETHOLOGY

SPRINGER TOKYO

Lugar: Tokyo; Año: 2015

0289-0771

Postnatal development of subterranean habits was investigated in Los Talas´ tuco-tucoCtenomys talarum, a subterranean caviomorph rodent endemic from South America.Since in this species, some key morpho-functional traits related to scratch-diggingbehaviour -a form of underground progression- are already present during earlyontogeny and develop progressively, we predicted that this behaviour expresses earlyduring postanatal development and its performance enhances gradually from pups toadults. The process of acquisition of different behaviours associated to the constructionof a burrow system was recorded in eleven individuals, each one coming from differentlitters, inside a terrarium filled with natural soil. We found that scratch-digging andburrowing behaviours expressed early during postnatal development, particularly,during lactancy. The digging of a "true burrow" clearly preceded the dispersal age, witha high inter-individual variability, from 18 (lactancy) to 47 (post-weaning) postnataldays. Pups could lose the soil using their foreclaws and remove the accumulatedsubstrate using their hindfeet as adults do. During lactancy individuals could constructa simple burrow to shelter, and first burrow construction occurred in the absence ofeither a burrowing demonstrator or an early subterranean environment (a natalburrow). However, certain features of the complex burrow system that characterize thisspecies, such as lateral branches and nest chamber, just appeared after weaning. Thetime elapsed until animals started to dig and the time dedicated to undergroundactivities varied with age, decreasing and increasing, respectively. In sum, our resultsshow that -in C. talarum- immature digging behaviour gets expressed early duringontogeny, and develops progressively. The role of the early ability to build its ownburrow and its possible function influencing the development of musculoskeletal traitsand on efficiency for such conduct is discussed