To add to Mike Denny's and Steve Mlodinow's comments about museums.

Most natural history museums these days save more than skin and bones. Most
now take tissue samples of all prepared specimens and freeze the samples.
At Conner Museum (WSU), we typically save muscle, liver, kidney, gonad, and
heart tissue (for mammals) and muscle, liver, kidney, heart, gonad, and
brain tissue (for birds).

The biggest use for tissue samples to date has been for systematic
(genetics) studies. They are also increasingly being used for stable
isotope, environmental contaminant, and pathogen (like bird flu) studies.
Stable isotope analysis of tissues can show differences in diet and, in the
case of birds, the source location of migratory birds. Saved tissues can be
used to study changes in environmental contaminants in wild animals. Tissue
samples undoubtedly have future uses that cannot be anticipated.

Dr. Kelly Cassidy
Curator, Conner Vertebrate Museum
Washington State University
Pullman, WA