Mastodon 300,000 years old The blood vessels found within the
bones of this American mastodon were, as seen here, mostly
crystalline—that is, gone to fossil and not soft. Only small fragments of
still-elastic vessels were uncovered. But like many of the other specimens, the
vessels were richly colored with possible blood products. Schweitzer and her
team have already speculated on how tissues might have survived for so long,
though the presence of soft vessels, the most easily degraded of tissues,
remains, they admit, "enigmatic." This bone also featured a
significant amount of preserved collagen matrix.
