TL;DR: Three species of hedgehog were chosen to represent temperate (Erinaceus europaeus), semi-arid (Hemiechinus auritus), and desert regions (Paraechinus aethiopicus) and all three species are competent temperature regulators which at low air temperature maintain bodyTemperature by increasing oxygen consumption, and at high air temperature by increasing the evaporation of water.
Abstract: Three species of hedgehog (Insectivora) were chosen to represent temperate (Erinaceus europaeus), semi-arid (Hemiechinus auritus), and desert regions (Paraechinus aethiopicus). Metabolic rates, temperature regulation, and evaporation of water were studied under laboratory conditions. All three species maintained their body temperature close to 34 C (about 3-4 C lower than other mammals). All three species are competent temperature regulators which at low air temperature maintain body temperature by increasing oxygen consumption, and at high air temperature by increasing the evaporation of water. The rate of oxygen consumption is lowest in the desert species (Paraechinus) and highest in the temperate species (Erinaceus). However, thermoregulatory abilities are similar in all three species and not readily correlated with their geographical distribution.
TL;DR: The results show that the large-sized nominate subspecies, Paraechinus hypomelas hypomelsas, is distributed throughout mainland Iran to the western side of the Indus River in Pakistan, suggesting the presence of a single subspecies from the entire Arabian Peninsula.
Abstract: The Persian Gulf harbours a group of islands off the Iranian coast, with known and distinct times of isolation, that are a result of sequential separation from the mainland because of rising sea levels subsequent to the last glaciation. In the present study, we examine the variation in the morphology of Brandt's hedgehogs Paraechinus hypomelas (Mammalia: Erinaceidae), both from these islands and mainland Iran, aiming to evaluate the effects of isolation time and to determine whether it conforms with the island rule. The results highlight a clinal variation along the sampled locations, closely reflecting the progressive historical isolation of the islands from the mainland, and complying with what could be expected given the island rule. The observed levels of morphological differentiation correlate with the timing of the hypothetical last faunal exchanges between Hengam, Larak, and Qeshm islands and the mainland. Additionally, subspecific taxonomy of the species throughout its distribution range in south-west Asia was revised using our extended information alongside available data from the literature. The results show that the large-sized nominate subspecies, Paraechinus hypomelas hypomelas, is distributed throughout mainland Iran to the western side of the Indus River in Pakistan, suggesting the presence of a single subspecies (Paraechinus hypomelas niger) from the entire Arabian Peninsula. Small-sized individuals from the Indus Valley in Pakistan (Paraechinus hypomelas blanfordi) and those from the first isolated island, Larak, clearly deviate from all other samples forming a distinct cluster, which provides a basis for the description of a new subspecies.