At least a dozen humpback whales dead on the banks in Northern California in recent weeks. From Monterey to Fort Bragg, via San Francisco
and Santa Cruz.   The last carcass came a few days ago in Point Reyes National Seashore. A macabre spectacle that is attracting hundreds of tourists and scaring the experts. Scientists are trying to determine whether there is a connection between whales beached whale and a possible example of "killer", given that the conditions of some specimens found suffered heavy mutilation. But they are taking into account climatic and environmental changes.   Some biologists Americans also claim that the deaths may be part of the annual migration of gray whales from Mexico to Alaska. But the mystery remains. The last major die-off of whales goes back to 1999 and to 2000, when they were found on the California bay about 40 specimens of gray whales. As then, also today, some specimens would be killed to killer whales, or by the action of fishing vessels.   For many specimens the causes of death are almost impossible to establish the conditions for carcasses. In addition, an anomaly concerns the very species they encounter while. While in the past it was just gray whales, with on average one or two casinel period, today in the 300 kilometers of beach were also found humpback whales and sperm whales. One of the theories to the study of researchers is based on the fact that the number of deaths this year might have something to do with a recent increase in population.   Both whales, gray and humpback whales, would reproduced bringing the historical population levels of the past, after the hunt the last 200 years had brought them almost to extinction. About 20 thousand humpback today inhabit the North Pacific and the cross. And to bring the carcasses to the shore, then, they may have been strong winds felled on the coast and the sea currents, regenerating what happened once when the remains of marine mammals were part of a perfect ecosystem, and beached carcasses were nothing a delicacy for grizzly bears, wolves, coyotes and California condor.