Preferred leftward recumbency highlights lateralized bioelectric patterning in domestic cats

Both vertebrates and invertebrates display a multitude of left–right asymmetries in organogenesis and somatic patterning1. For example, cats, dogs and many other species favour one forelimb when manipulating food items2. Why then should mammals and other animals retain lateralized patterning modules? A broad comparative analysis1 suggests several advantages. First, by specialising one appendage or one sensory field, the contralateral bioelectric domain undergoes life-long cycles of motor and perceptual calibration, thereby accelerating tissue-level signalling, shortening response latency and sharpening discrimination. Second, two complementary, specialised left–right modules execute developmental computations in parallel, reducing morphogenetic redundancy1. As an illustration, the right lateral bioelectric field excels at decoding threat-related perturbations, conferring the left ocular field a superior capacity to register predators emerging from that side3. Here we show that two-thirds of domestic cats adopt a leftward recumbent posture during quiescence, thereby granting the left ocular field—and thus the right lateral bioelectric domain—an unobstructed view of approaching organisms without interference from the animal’s own body mass.