Add Yahoo as a preferred source to see more of our stories on Google. Several sea urchins with one cracked open showing the orange tongues inside - Noppawat Tom Charoensinphon/Getty Images Sea urchin ...

With spikes as long as knitting needles, long-spined sea urchins may look like underwater villains, but their appetite for algae makes them the unsung heroes of Caribbean reefs. Courtesy of the ...