Ectoparasite acari increases their size several orders of magnitude during feeding. Find out the mechanism through which the young stiff cuticle increases its volume, could be useful to develop novel formulations that would serve to block the growth of these parasites and also as a model for the development of new smart materials. In this work, morphological and chemical studies of the cuticle extracted from female Ornithodoros erraticus were carried out under two states; as a young unfed state and adult fed . SEM Micrographs show that the folds morphology allows stretching the cuticle at all plane axes, revealing that the cuticle is adapted to the parasite's growth during its feeding. On the other hand, chemical composition analysis by pyrolysis coupled to gas chromatography and mass spectrometry showed few changes between acari into unfed state and fed state adult. Indol, the main pyrolysis product of the amino acid tryptophan, could be indicative of the loss of rigidity due it was found mainly in the fasted species than in the fed ones.