Graded calls of the smallest terrestrial mammal, the Etruscan shrew, living in a closed habitat.

Graded call types predominate in species inhabiting open habitats with complex social systems, whereas discrete call types predominate in species with simple social systems living in closed habitats. This study aims to establish the vocal repertoire of Etruscan shrews, the smallest terrestrial mammal, which lives in pairs in closed habitats. Through various behavioral experiments, vocalizations were recorded and analyzed using unsupervised soft clustering, identifying four call types, one of which exhibited gradation.

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Drumming is a non-vocal auditory display producing airborne as well as seismic vibrations by tapping body extremities on a surface. It is mostly described as an alarm signal but is also discussed to signal dominance or mating quality. To clarify the function of drumming in Mongolian gerbils (Meriones unguiculatus), we compared the occurrence of drumming during predator, opposite-sex and same-sex encounters.

Anatomy of superior olivary complex and lateral lemniscus in Etruscan shrew.

Based on the auditory periphery and the small head size, Etruscan shrews (Suncus etruscus) approximate ancestral mammalian conditions. The auditory brainstem in this insectivore has not been investigated. Using labelling techniques, we assessed the structures of their superior olivary complex (SOC) and the nuclei of the lateral lemniscus (NLL).

GABA receptor-mediated modulation in the developing dorsal nucleus of the lateral lemniscus.

The dorsal nucleus of the lateral lemniscus (DNLL) is a GABAergic, reciprocally connected auditory brainstem structure that continues to develop postnatally in rodents. One key feature of the DNLL is the generation of a strong, prolonged, ionotropic, GABA receptor-mediated inhibition. Possible GABA receptor-mediated signalling is unexplored in the DNLL.

Timing and precision of rattlesnake spinal motoneurons are determined by the KV7 potassium channel.

The evolution of novel motor behaviors requires modifications in the central pattern generators (CPGs) controlling muscle activity. How such changes gradually lead to novel behaviors remains enigmatic due to the long time course of evolution. Rattlesnakes provide a unique opportunity to investigate how a locomotor CPG was evolutionarily modified to generate a novel behavior-in this case, acoustic signaling.