"You are what you eat." This is true not only for humans, but extinct mastodons as well. Scientists have drilled holes in the teeth of both the Hyde Park and Gilbert Mastodons and are analysing the chemistry of these cuttings. As an amimal eats, certain chemical ratios of the food he/she eats becomes incorporated into the animal's bones and teeth. It is therefore possible to determine, for example, whether or not an extinct animal ate meat or was strictly vegetarian. Isotopic ratios from the Gilbert Mastodon reveal that this animal ate more than just grass - this animal was a browser, eating spruce twigs and other vegetable matter. There are those that speculate that Cornell's Gilbert Mastodon was possibly a scavenger (a case made stronger by the serated teeth of the mastodon, as well as soem of the isotopic numbers from the teeth), but this is, at this point, still purely speculative.