Fighters, not lovers? High concentrations of PCBs could be damaging male polar bears’ ability to mate. Hoberman Collection / UIG / Getty Images

The existential threat that climate change poses to polar bears has long been a concern, but now scientists have yet more worrying news for the Arctic predator. A new study has put into focus the potential damage that a chemical pollutant is having on their, um, bear necessities. More to the point, it could be making penises more fragile.

Researchers have already said that polychlorinated biphenyls, or PCBs, could become concentrated in the polar regions because of a process called global distillation, in which chemicals are transported from warmer to colder parts of the globe.

It is also known that the chemical attacks vital organs and tissues, like bone.

Which is bad news for polar bears, which have a penile bone, or baculum. A weaker baculum could be easily fractured or broken, threatening successful mating in an already at-risk species, researchers said.

Christian Sonne at Aarhus University, Denmark, and his team theorized that PCBs could have a serious impact on the species’ survival. The study, “Penile Density and Globally used Chemicals in Canadian and Greenland Polar Bears,” documents their investigation into the theory.

The scientists looked at baculum strength in eight polar bear populations. They were able to gather samples easily because hunters in the region often take penis bones as proof that they killed a polar bear, New Scientist reported.

Researchers found that bears in areas with the highest concentration of PCBs had the most fragile penis bones — seemingly corroborating the theory.

PCBs have been banned since 2001, but it takes time to break down in the environment.

There may be a happy ending for polar bears, however. When the chemical’s concentrations finally ebb, it is likely that polar bears' penises will again strengthen.