Are chemicals shrinking otter penis bones?

CARDIFF U. (UK) — Despite a population increase, male otters show negative changes in their reproductive organs, according to a new report that asks if endocrine disruptors are to blame.

The authors of the report looked at several indicators of male reproductive health and found several signs of change that give cause for concern:

  • A decrease in penis bone (baculum) weight over time
  • An increase in cysts on the tubes that carry sperm during reproduction (vas deferens)
  • An increase in undescended testicles (cryptorchidism)

It is not possible to determine exactly what the causes of these changes are, but various studies, both in the laboratory and in wildlife, have suggested links between hormone-disrupting chemicals (EDCs) and problems with male reproductive health.


“The otter is an excellent indicator of the health of the UK environment, particularly aquatic systems,” says Eleanor Kean of Cardiff University’s School of Biosciences.

“Our contaminant analyses focused on POPs that were banned in the 1970s, but which are still appearing in otter tissues now—other chemicals, in current usage, are not yet being monitored in wildlife. There is a clear need to regularly revise the suite of contaminants measured—failure to do so may lead to a false sense of security and cause emerging threats to otters and UK wildlife to be missed.”

“If we are to protect our wildlife, we need good information on the reproductive health of key species in both the terrestrial and aquatic environments,” adds Gwynne Lyons, director of the Chemicals, Health, and Environment Monitoring Trust (CHEM Trust).

“These findings highlight that it is time to end the complacency about the effects of pollutants on male reproductive health, particularly as some of the effects reported in otters may be caused by the same EDCs that are suspected to contribute to the declining trends in men’s reproductive health and cause testicular cancer, undescended testes, and low sperm count.”

CHEM Trust is calling for the UK Government and the European Union to urgently identify hormone disruptors to ensure that chemicals suspected of playing a role in male reproductive health problems are substituted with safer alternatives.

Kean and Elizabeth Chadwick are researchers with the Cardiff University Otter Project.

Source: Cardiff University