Scientist Robert Garrot, Montana State University, addresses a group of ParKids in the Yellowstone Park School. He is pointing to a projected slide of an elk grazing in a hydrothermal area in Yellowstone.
Garrot: Guess what? The geology of this area—this is all volcanic soil—and that volcanic is super high—the highest soil in the world—in silica content. Silica is harder than good teeth. So, if you eat a lot of silica, it grinds down your teeth really fast. So the geology of the area here (pointing to projected image) does two things. First of all, they (the elk) eat too much fluoride and that makes their teeth soft and then every bite of plant material that they take is covered with a little dust from the soil, and that dust has silica in it and it grinds their teeth down really fast. So, if you took—now to show you, here a picture (pointing to a projected slide of five elk jaws), but I’ve got a prop here (indicates a plastic bag).
Are you guys squeamish? Can I take this out of the bag or should I pass it around in the—
ParKids: No! Take it out!
Garrot: All right! All right! That’s what I like! (Removes an elk jaw and shows it to the ParKids) All right. Does that look like an elk that’s been eating in a geothermal area? Look at those teeth.
ParKids: Uh huh! No! No!
Garrot: They look as good as my teeth! (Holds jaw up to his own mouth and shows his teeth). They look healthy, don’t they?
ParKid: They look good!
Garrot: Now, what are characteristics about those that make them good?
ParKid: They’re white!
Garrot: They’re white.
ParKid: And they’re not broken.
Garrot: Yeah. You’ve got a nice even wear (shows a close up of the elk jaw). How old do you think this animal is? Well, let me tell you one thing. Many animals that depend on plants, what dictates how long they can live is how good their teeth are. When their teeth wear out, they can’t chew plants well. If they can’t chew them well, they can’t digest—they’re dead. So do you think this girl has a long time to live yet?
Garrot: She’s got a lot of teeth left. Guess how old she is?
Garrot: No, older.
Garrot: Too old. Split it in half!
ParKid: Fifteen! Fifteen!
Garrot: Fifteen. This is a 15 year old cow elk that was killed by a wolf up here in the Northern Range, by the Lamar River, where there is very little geothermal activity—none of this chemistry that I’ve been talking about at all. And look at her teeth—they’re nice! If a wolf hadn’t killed her, she wouldn’t have died from starvation because her teeth were worn out, for many, many years yet. Okay? So, you guys can take a look at that (He hands jaw to the students and removes a second jaw from the plastic bag.) Now, here is another girl—
Garrot: From the central part of the park.
ParKids: That looks bad, really bad! The jaw!
Garrot: So think about your own teeth, okay? Have you ever had a cavity? Yeah, look at that! Look! The bone is porous. (Close up of jaw showing uneven teeth and deep cavity.) She’s had infections down into her bones!
Garrot: That’s way below the gum line! And look at this one! (Indicates other tooth) If we looked at the top of her teeth, these have cut all the way through the roof of her mouth. These? (showing high sharp teeth) And these (showing deep depression) are all worn out, clear down into her jaw.
ParKid: Oh, my!
Garrot: Now how old do you think she is?
ParKid: Five or something? Five? Ten?
Garrot: Well, no, she’s 12. And she died because her teeth wore out. And that one’s 15—and she would have probably lived another ten years.