The senses supply the brain with information about the physical world. They have, of course, to obey the same laws of nature as engineered devices. However, biological systems have access to different materials than human engineers and evolution is an effective optimization mechanism. I will present two sensory systems that at first sight seem to defy the laws of nature, providing their owners with vital information that seems to be impossible to obtain with the available means. One of the systems, i.e. the eyes of fish, we understand reasonably well. The other system, i.e. the infra-red sensitive nose tips of dogs, we have just begun to study.