Why do some researchers say there are seven species of sea turtles and some say there are eight species?
The difference in number is based on whether or not the black sea turtle is a separate species from the green sea turtle. The debate centers on the genetic difference between the green sea turtle and the black sea turtle. Most sea turtle researchers believe that the black sea turtle should be called the Pacific green turtle because it is a sub-species of the green sea turtle and, as a result, has almost identical genetic traits. Some sea turtle researchers believe that the physical characteristics and other behavioral difference indicate that it should be classified as its own species.
