A culture so advanced, and by condition of the teeth
The archaeologists will see that the teeth of the skulls are not as rotten as they have been in the past due to better dental care products and dentists or that they are false teeth and have been replaced because of the latter.
Also, a reference to how in the wild most herbivores have small, straight teeth while carnivores have long, sharp fangs. With the line following about barbarianism, Lupe’s saying that the people clearly weren’t savage and violent as most ancient humans are perceived to be.
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