Dentin samples were obtained from teeth of T. truncatus specimens collected in South Brazil, which were stored dry in the Marine Mammal Laboratory of the Universidade Federal do Rio Grande - FURG (Table 1). Preparation of material for storage in this collection was done by maceration of the skull in water, followed by cleansing with detergent. Skulls were then whitened with commercial grade sodium hypochloride before incorporating them into the collection.