Minimus is Pliny the Elder and Silvius is his nephew Pliny the Younger. Minimus is reading to Silvius from his writing tablet. There's a hedgehog between them. with apples stuck on its spines. Minimus is quoting Pliny's Natural History 8.58: praeparant hiemi et echini cibos ac volutati supra iacentia poma adfixa spinis, unum amplius tenentes ore, portant in cavas arbores (Hedgehogs also prepare food for winter and, having rolled on fallen fruit and stuck it to their spines, holding one more fruit in their mouths, they carry it into hollow trees). Pliny's mistaken idea was widely believed for centuries - even Darwin fell for it!
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