Sastrugi Sastrugi Sastrugi, or zastrugi, are sharp irregular grooves or ridges formed on a snow surface by wind erosion, saltation of snow particles, and deposition, and found in polar and open sites such as frozen lakes in cold temperate regions. The ridges are usually perpendicular to the prevailing winds; they are steep on the windward side and sloping to the leeward side. Smaller irregularities of this type are known as ripples (small, ~10 mm high) or wind ridges. Larger features are especially troublesome to skiers and snowboarders. Traveling on the irregular surface of sastrugi can be very tiring, and can risk
Surface wave detection by animals surface wave detection ability, and it is easily housed and trained in laboratories. Pantadon bucholzi (a surface dwelling butterfly fish) is used less often though is very similar in its anatomy and behavior. The rest of this article will focus on research done with "A lineatus". "(See the work of Bleckmann, Schwartz, Müller, etc., 1965-present)." The experimental setup for testing "A lineatus"' abilities is very standardized. Subject fish are often blinded so that visual cues cannot be used. Stimuli are delivered to the surface of the water in a test tank via one of two methods (experimenters often use both):