Message #148718

[Bianca]

               

The earliest magnetic sculpture discovered in Mesoamerica was this carved turtle-head located about 30 m (100 ft) off the main pyramid of Group F at Izapa, identified by the author in 1975. In the inventory of monuments compiled at the site, this was catalogued as A 54.

 







               Once the sculpture's magnetic properties had been identified and measured, I had my students undertake a survey of all the other exposed rock at the site to determine whether this was a unique or commonplace occurrence. When the survey revealed that this was the only magnetic sculpture which could be identified, I felt confident in concluding that its carver must have purposefully reserved this magnetite-rich boulder for his representation of a turtle. But then the question arose -- what could have prompted him to associate magnetism with a turtle?

               When I reported this discovery to the scientific community in the journal Nature in February 1976, the editor permitted me one sentence of speculation -- to wit, might the carver have somehow come to associate the uncanny homing instinct of turtles with magnetism?

At the time the article was published, such speculation had little supporting evidence to back it up. Indeed, one of the world's most eminent specialists on turtles, Archie Carr of the University of Florida, had only recently completed an intensive investigation of the navigational abilities of this reptile for the Office of Naval Research but was forced to conclude, after testing every conceivable hypothesis, that he still didn't know how they did it; when it came to magnetism, all he could say was that he could not rule it out (Carr, 1967, 171). Of possible relevance to the question at hand, however, was a reference which Carr made to a deep-carapaced black turtle that migrated from the Galápagos Islands to lay its eggs on a limited stretch of black-sand beach in Soconusco.

Not only were other species of turtles well known within the region because of the periodic migrations of loggerheads and leathernecks north and south along the shore, but since time immemorial the turtle had served as one of the preferred sources of meat.

Although Carr was of necessity cautious and noncommital, recent research in zoology increasingly suggests that not only turtles but also birds and even some worms may orient themselves by using the earth's magnetic lines of force, so what may have been a questionable speculation in 1976 has now become an area for serious inquiry (Seachrist, 1994, 661).