Sastrugi breaking equipment—ripples and waves are often undercut and the surface is hard and unforgiving, with constant minor topographic changes between ridge and trough. The words "sastrugi" and "zastrugi" are Russian-language plurals; the singular is "sastruga" or "zastruga". The form "sastruga" started as the German-language transliteration of the Russian word заструга (plural: заструги). A Latin-type analogica singular "sastrugus" is used in various writings on exploration of the South Pole, including Robert Falcon Scott's expedition's diaries and Ernest Shackleton's "The Heart of the Antarctic". Under the action of steady wind, free snow particles accumulate and drift like the sand grains in barchan
Surface wave detection by animals that further analysis of waves must happen at higher levels in the nervous system. The African clawed frog ("Xenopus laevis") responds to surface waves. It is able to locate wave directions at least to within ± 5° and they can localize and distinguish between two different water waves coming simultaneously from two insects in different directions. Xenopus has approximately 200 lateral-line organs located along the sides of its body, and also around its eyes, head and neck. It is claimed these are used to navigate and detect prey either striking the water or struggling but the role of these organs