Evidence from archaeological sites in the medieval English city of Winchester shows that English red squirrels once served as an important host for Mycobacterium leprae strains that caused leprosy in people, researchers report May 3 in the journal Current Biology.

A team of researchers from Texas A&M University and beyond has made a surprising discovery about rising mercury levels in Steller sea lion pups that may have detrimental effects on the endangered species. 

The team’s decade-long effort to study mercury in Steller sea lions in the Aleutian Islands — the strip of islands stretching between Russia and Alaska and separating the Bering Sea and Pacific Ocean — has revealed that the number of pups born with potentially dangerous levels of mercury in their blood and fur increased by more than 50% from 2011 to 2018 before leveling off in 2019. 

In a recent paper, PIK Professor Michael Platt and the Perelman School of Medicine’s Peter Sterling posit that the underlying mechanism of the looming concern of human fertility declines is the epidemic of despair. In a Q&A with Penn Today, Platt discusses his motivations for this investigation and shares further insights.