animal locomotion on the surface layer is the study of animal locomotion in the case of small animals that live on the surface layer of water, relying on surface tension to keep afloat. In biology and physics, animal locomotion is the study of how animals move, and is part of biophysics. ... Phyla Porifera (sponges) Ctenophora (comb jellies) Cnidaria Placozoa Subregnum Bilateria  Acoelomorpha  Orthonectida  Rhombozoa  Myxozoa  Superphylum Deuterostomia     Chordata (vertebrates, etc. ... Water (from the Old English word wæter; c. ... In physics, surface tension is an effect within the surface layer of a liquid that causes the layer to behave as an elastic sheet. ...

There are two means of walking on water: the regime is determined by the ratio of the animal's weight mg to the maximum vertical force that can be exterted by the surface layer (σP, where σ is the surface tension and P is the contact perimeter of the animal's feet). Creatures such as the basilisk lizard have mg / (σP) > 1 and are discussed on animal locomotion by water-walkers. Weight is the interaction of matter with a gravitational field. ...

Surface living animals such as the water strider typically have hydrophobic feet covered in small hairs that prevent the feet from breaking the and becoming wet. Water striders in particular are known to have feet that have minute hairs on them. Genera Aquarius Gerris Halobates Limnogonus Limnoporus Metrobates Neogerris Rheumatobates Trepobates The Water strider, (also known as: Skater, Pond Skater, Jesus Bug, Water Skeeter, water scooter, water skater, Skimmer is any of a number of predatory insects in the family Gerridae (Leach 1815) that rely on the surface tension of water... In chemistry, hydrophobic or lipophilic species, or hydrophobes, tend to be electrically neutral and nonpolar, and thus prefer other neutral and nonpolar solvents or molecular environments. ... Hair is the filamentous outgrowth of the epidermis found in mammals. ...

There are at least 342 species of water striders, according to biophysicist David L. Hu (Nature, vol 424, p663, August 2003). As striders increase in size, their legs become proportionally longer, with Gigantometra gigas having a length of over 20 cm and a weight of about 40 millinewtons. Biophysics (also biological physics) is an interdisciplinary science that applies theories and methods of the physical sciences to questions of biology. ...

Water striders generate thrust by shedding vortices in the water: a series of "U"-shaped filaments is created during the power stroke. The two free ends of the "U" are attached to the water surface. These vortices transfer enough (backward) momentum to the water to propel the animal forwards. Vortex created by the passage of an aircraft wing, revealed by coloured smoke A vortex is a spinning turbulent flow (or any spiral whirling motion) with closed streamlines. ...

See also Denny's paradox, robostrider. In the study of animal locomotion, Dennys paradox refers to the apparent impossibility of surface-dwelling animals such as the water strider generating enough propulsive force to move. ...