Whether froglets switch sexes distinguishes ‘sex races’
Amphibian starts all female in one region of Europe; in another, with gonads of either sex
![common frog](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/04/sm_ranafrog_free.jpg?fit=860%2C460&ssl=1)
OFF TO THE RACES What’s called the common frog in Europe (shown here in Switzerland) is one widespread species even though different races vary in their potentially sex-reversing lifestyles.
Andreas Meyer