Lady Into Fox by David Garnett (1892 - 1981)
LibriVoxWhen Sylvia Tebrick, the 24-year-old wife of Richard Tebrick, suddenly turns into a fox while they are out walking in the woods, Mr. Tebrick sends away all the servants in an attempt to keep Sylvia's new nature a secret. Both then struggle to come to terms with the problems the change brings about. (Summary by Annise)