Master's Defensio


Karoline Bürger BSc

Population Structure and Activity Pattern in a Dalmatian Tortoise (Testudo hermanni hercegovinensis) Population

Advisor: Walter Hödl

Master's Defensio - Monday, April 12th 2021


Only a few field studies of Testudo hermanni hercegovinensis, a subspecies of Testudo hermanni,
have been carried out so far. In order to learn about the population structure and daily activity
patterns of this species, we focused on sex and age specific differences in body size and
behaviour. In May 2014 and 2015 we collected data of 500 individuals within a study area sized
±1.5 km² near Dazlina/Croatia. In contrast to other studies, the sex ratio was strongly femalebiased
(2.06) and individuals of both sexes were in general larger than expected. Males were on
average 2.49 cm smaller than females and showed a significant relationship between size and
mobility. They also were mostly medium-sized, which indicates that there might be a compromise
between mobility, inter- and intraspecific competition, predation and metabolism. Females, on
the other hand, were mostly large-sized. Regarding activity patterns, we observed that behaviour
types such as basking, resting, moving or foraging were not evenly distributed throughout the day.
We found that inactive behaviour dominated with 60 - 80% of the daily observation hours. With
the exception of basking which was most frequent in juveniles, no significant activity differences
between males, females and juveniles were found.