Nov. 5, 2010 A centuries-old religious ceremony of an indigenous
people in southern Mexico has led to small evolutionary changes
in a local species of fish, according to researchers from Texas
A&M University. Since before the arrival of Christopher Columbus
to the New World, the Zoque people of southern Mexico would
venture each year during the Easter season deep into the
sulfuric cave Cueva del Azufre to implore their deities for a
bountiful rain season. As part of the annual ritual, they
release into the cave's waters a distinctive, leaf-bound paste
made of lime and the ground-up root of the barbasco plant, a
natural fish toxin. Believing the cave's fish to be gifts from
their gods, they scoop up their poisoned prey to feed upon until
their crops are ready to harvest. However, a team of researchers
led by Dr. Michael Tobler, an evolutionary ecologist at Oklahoma
State University, and Dr. Gil Rosenthal, a biology professor at
Texas A&M, has discovered that some of these fish have managed
not only to develop