Crocodilians Are Promising Intermediate Model Organisms for Comparative Perception Research
Crocodilians are the closest living relatives of birds and share many ecological challenges with mammalian apex predators. They evolved perception pathways that share similarities with both taxa, birds and mammals. Due to their position in the tree of life, crocodilians therefore represent a promising intermediate model for comparative research. In this review, the different modalities of perception in crocodilians are discussed: vision, audition, olfaction, gustation, sense of touch, and (the potential for) magnetoreception. The anatomy and physiology of the sensory organs are briefly described, and behavioral studies on perception summarized. Throughout the review, the similarities and differences between crocodilians and other vertebrate taxa are addressed. Overall, crocodilian sensory organs seem to have evolved for a terrestrial environment, as their eyes are adapted for vision in air, their hearing resembles that of birds, and they do not seem to use olfaction under water. A clear exception are the integumentary sensory organs, which allow them to perceive minute water movements. While crocodilian sensory organs have received quite some attention, there are relatively few behavioral studies on perception. Future research on the perceptual capacities of crocodilians will provide insight into the evolutionary origins of perception in all amniotes.
Keywords: vision, communication, olfaction, integumentary sensory organ