# Jumping Locomotion Strategies: From Animals to Bioinspired Robots
## 2 Jumping Animals and Biomimetic Miniature Jumping Robots
### Specialized Jumping Performance: Aquatic Environments  
Aquatic environment is a new area for jumping robots to survive. There are some animals skilled at jumping in aquatic environments, such as water striders [179], mole crickets [180], flies _Hydrohorus_[181], which can jump on water; archer fishes [182] and dolphins can jump out of water in order to communicate or catch preys; and crabs [183] have a very special locomotion mode, named \"punting\" in the bottom of water.  
For animals jumping on water, a lot of different strategies exist. Small size creatures, like water stricter, use their superhydrophobic hind and middle legs [179] to exploit surface tension and generate thrust. In flies' take-off, the use of both jumping and flapping increases the take-off velocity and decreases the take-off time with respect to take-off only relying on flapping from the water surface. They jump relying on the direct actuation of middle legs and hind legs without penetrating the water surface and make use of the surface tension of water [181]. Meanwhile, big size animals, like frogs [184] and basilisk lizards [185; 186; 187], also use the surface tension to run on water by generating a turbulent flow beneath their wide and flat feet. Basilisk lizards have to maintain a pocket above their feet. Mole crickets and copepods exploit water viscosity to jump. In pygmy mole crickets, jumping is powered by rapid extension of the hind tibiae as other orthopteran insects [188]. In addition to the excellent jumping performances on the ground, they can also jump on water [180]. Thanks to a unique array of spring-loaded paddles and spurs that increase the contact area, pygmy mole crickets move their powerful hind legs so quickly that they penetrate the surface as they move through the water. Catapult mechanism is used to move the tibiae very quickly to generate big forces through a laminar flow of water beneath hind tibiae.  
Animals that can jump out of water adopt different strategies. Famous jumpers like dolphins accelerate their bodies from the bottom of the water and use the accumulated momentum when they arrive at the water surface to break the water. Archer fishes use a gentler way, and they can generate thrust from a still position close to the water surface, jumping out of water. In addition to the use of shooting, they also exploit jumping to catch preys [189], mainly when several fish are gathered together and the situation is more competitive [182; 190]. Through kinematics and hydrodynamics analysis of archerfish jumping, [PERSON] et al. found that archer fishes use their tail in combination with anal, pectoral, and dorsal fins to generate enough thrust from still position in order to jump out of water, and they also want to design an archer fish-inspired robot that can jump smoothly from water.  
Some animals adopt leg locomotion to move in the bottom of water; for example, crab, octopus, and lobster. A new locomotion mode adopted by crab, which is named \"punting\", has been discovered and gave inspirations to researchers to design a new generation of underwater vehicles that use legs to move [183].  
In this part, the jumping mechanisms and performances of aquatic animals, including water-strider, dolphin, and crab, are introduced. In addition, the research statuses of the corresponding bioinspired jumping robots are reviewed.