Evolution of sensory specializations in insectivores
Article first published online: 7 OCT 2005
Copyright © 2005 Wiley-Liss, Inc.
The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology
Special Issue: Nature's Experiments in Brain Diversity
Volume 287A, Issue 1, pages 1038–1050, November 2005
How to Cite
Catania, K. C. (2005), Evolution of sensory specializations in insectivores. Anat. Rec., 287A: 1038–1050. doi: 10.1002/ar.a.20265
- Issue published online: 25 OCT 2005
- Article first published online: 7 OCT 2005
- Manuscript Accepted: 17 AUG 2005
- Manuscript Received: 16 AUG 2005
- NSF. Grant Numbers: 0518819, 0454761, 0238364
- Eimer's organ
Although insectivores have traditionally been thought of as primitive mammals with few specializations, recent studies have revealed great diversity in the sensory systems and brain organization of members of this mammalian order. The present article reviews some of these findings in three insectivore families that are thought to form a monophyletic group. These include hedgehogs (Erinaceidae), moles (Talpidae), and shrews (Soricidae). Members of each group live in unique ecological niches, have differently specialized senses, and exhibit different behaviors. Hedgehogs have well-developed visual, auditory, and somatosensory systems. Shrews make use of visual and auditory cues, but appear to depend most heavily on touch, particularly through prominent vibrissae. Moles are somatosensory specialists with small eyes and ears and unique epidermal mechanoreceptors called Eimer's organs used to identify prey and investigate their environment. In contrast to historical views of the insectivore order, members of this group have discrete and well-organized cortical sensory areas with sharp borders as determined from both electrophysiological mapping and analysis of cortical histology. Comparison of cortical organization across species reveals a number of specializations, including expansion of cortical representations of important sensory surfaces, the addition of cortical areas to some processing networks, and the subdivision of areas into separate cortical modules. In the case of the star-nosed mole, the somatosensory system has a tactile fovea and shares a number of features in common with the visual systems of sighted mammals. © 2005 Wiley-Liss, Inc.