Study on the differences of BMI between olms found in cave and the ones sampled in spring

The olm (Proteus anguinus) is a blind amphibian, depigmented and with an extremely reduced metabolism. These are adaptations to cave life that allow the animals to exploit this hostile (from a human perspective) habitat. Adaptations to cave life, should prevent successful exploitation of the external environment. However, although the Proteus is a cave animal, it has been reported by some authors in the spring environment, Our previous results showed that this presence, would seem not to be random, in but linked to very specific factors such as hydroperiod the absence of potential predators. In the light of these results, we have conducted a study with the aim of verifying whether the Proteus benefits from exploiting the trophic resources occurring in springs. Since June 2020 we have sampled 64 springs and 12 caves in the Monfalcone province, each olm found during the sampling was photographed, measured and weighed. A total of 73 different olms were analyzed and the Body Mass Index (BMI) was calculated for each individual. Olms found in springs had a significantly higher BMI than those found in caves. The BMI of springs’ olms was significantly related to amount of the trophic available, evidencing that they took advantages from exploiting the external environment. These results contribute to support the hypothesis of the non-random presence of the Proteus in the spring environment, the olm, in fact, seem to benefit from this type of habitat taking advantage of the greater number of resources present in it.