It exists in two versions, both believed to be authentic works of Caravaggio, one in the Fondazione Roberto Longhi in Florence, the other in the National Gallery, London.

Fried argues that the subject's hands – one stretched out, the other raised up – are in a similar position to those of a painter holding a palette while painting.

The salamander also had phallic connotations, and the painting might have been inspired by a Martial epigram: "Ad te reptanti, puer insidiose, lacertae Parce: cupit digitis illa perire tuis.

Critics of Caravaggio's insistence on painting only from life would later point out this limitation of his method: it lent itself to marvelously realistic (if theatrical) static compositions, but not to scenes involving movement and violence.

[2] As was first suggested by Roberto Longhi, Caravaggio has probably borrowed the motif of biting a finger from a Boy Bitten by a Crab, a drawing by prominent Renaissance artist Sofonisba Anguissola.