Falke's Captive by Madison Layle & Anna Leigh Keaton, read by my alter ego "Elizabeth Matthews".
A graduate student working in animal genetics, Beth Coldwell is in town to track and tag big cats in the wild. Her prospects for the summer only improve when she meets Kelan and Reidar Falke and decides the sexy brothers are the right pair to fulfill her other, less than scientific, desires... But her research is a threat to the Falke family secret. When Kelan, in cougar form, is captured, that secret comes closer than ever to being revealed. He escapes, but not before Beth draws a blood sample, and analysis shows this is no ordinary mountain lion. Kelan and Reidar cannot deny the powerful attraction they feel toward Beth. She might just be their destined mate. But if they reveal themselves to her, will she embrace who they are or see them as just another science experiment?
The book has a 4 out of 5 star rating among the PNR crowd--that's paranormal romance, for the uninitiated. In case the cover didn't tip you off, this saucy audiobook contains adult situations and is NOT for the family car trip. Save it for your earphones.