Sockeye salmon for courtship. If they waste too much energy, they might not be able to spawn. Males must also make the decision whether to invest energy in fighting for a female or for longevity on the spawning grounds. Aggressive behavior displayed by dominant males is predominantly directed towards intruding dominant males. Sometimes sockeye salmon males behave aggressively towards subordinate males. These encounters are short, with the intruding male leaving after one or two aggressive interactions. Spawning females direct their aggression primarily towards intruding females or other spawning females that are close by. However, they may also direct aggression towards intruding or
Robot fish Robot fish A robot fish is a type of bionic robot, which has the shape and locomotion of a living fish. Since the Massachusetts Institute of Technology first published research on them in 1989, there have been more than 400 articles published about robot fish. According to these reports, approximately 40 different types of robot fish have been built, with 30 designs having only the capability to flip and drift in water. Most robot fish are designed to emulate living fish which use Body-caudal fin (BCF) propulsion. BCF robot fish can be divided into three categories: Single Joint (SJ), Multi-Joint