Say you're a polar bear walking around Svalbard, a chain of Arctic islands between Norway and the North Pole. You eat mainly seals. In spring, after emerging from hibernation, you'll eat the whole seal, but later in the year, you might slit the seal open and, what the heck, just eat the fat. You've been doing this forever. But in the past 10 years, you may have changed into a sexual freak. At this stage of the game, there's a one in 100 chance that you possess both male and female reproductive organs.
Hermaphrodism affects wildlife all over the world, and is thought to be caused by the animals' exposure to chemicals that affect the endocrine system. Scientists in Svalbard believe that the increase in hermaphroditic polar bears can be blamed on PCBs (polychlorinated biphenyls) that are damaging their immune systems. Around 1.2 percent of Svalbard's 3,000 bears are now affected.
Originally manufactured for use in electrical equipment, PCBs have been banned by many countries, but a reservoir of the chemicals has escaped and contaminated the environment. Prevailing southerly winds blow the pollution from industrial areas of Europe up to the Svalbard islands.
"There is a very short and simple food chain here -- plankton, fish, seals and finally the bears themselves," said Per Kyrre Reymert of the Svalbard Science Forum. "So it is fairly easy to track PCBs and other pollutants."
Many species are affected by the pollution, including sea gulls, but with most endocrine problems, males experience the genital abnormalities. With these poor polar bears, it's the exact opposite, says environmental expert Elizabeth Salter. "It seems to be the female bears on Svalbard that are acquiring male genitalia, a penislike stump," said Salter.
As the climate changes and more of the polar ice cap melts, the bears are expected to come ashore to the small settlements on the Svalbard islands. Residents are advised to be on the lookout for hungry, hermaphroditic polar bears.