fig1

Figure 1. Different olfactory patterns. (A) The main olfactory system of humans^[3]; (B) The vomeronasal organ of a dog. This figure is quoted with permission from MDPI^[7]; (C) The aquatic olfaction of sharks. This figure is quoted with permission from The PLOS One^[10]; (D) The stereo olfaction of snakes; (E) The pheromone communication of insects.