reach the coast, and are scavenged, or decompose enough to sink to the ocean bottom, where the carcass forms the basis of a unique local ecosystem called a whale fall. Individual strandings Single live strandings are often the result of individual illness or injury; in the absence of human intervention these almost always inevitably end in death. Multiple strandings Multiple strandings in one place are rare, and often attract media coverage as well as rescue efforts. The strong social cohesion of toothed whale pods appears to be a key factor in many cases of multiple stranding: If one gets into trouble, its distress calls may prompt the rest of the pod to follow and beach themselves alongside. Even multiple offshore deaths are unlikely to lead to multiple strandings, since winds and currents are variable, and will scatter a group of corpses. Environmental Whales have beached throughout human history, with evidence of humans salvaging from stranded sperm whales in southern Spain during the Upper Magdalenian era some 14,000 years before the present. Some strandings can be attributed to natural and environmental factors, such as rough weather, weakness due to old age or infection, difficulty giving birth, hunting too close to shore, or navigation errors. In 2004, scientists at the University of Tasmania linked whale strandings and weather, hypothesizing that when cool Antarctic waters rich in squid and fish flow north, whales follow their prey closer towards land. In some cases predators (such as killer whales) have been known to panic other whales, herding them towards the shoreline. Their echolocation system can have difficulty picking up very gently-sloping coastlines. This theory accounts for mass beaching hot spots such as Ocean Beach, Tasmania and Geographe Bay, Western Australia where the slope is about half a degree (approximately deep out to sea). The University of Western Australia Bioacoustics group proposes that repeated reflections between the surface and ocean bottom in gently sloping shallow water may attenuate sound so much that the echo is inaudible to the whales. Stirred up sand as well as long-lived microbubbles formed by rain may further exacerbate the effect. A 2017 study by scientists from Germany's University of Kiel suggests that large geomagnetic disruptions of the Earth's magnetic field, brought on through solar storms, could be another cause for whale beachings. The authors hypothesize that whales navigate using the Earth's magnetic field by detecting differences in the field's strength to