Divergence Linked to Possible Ecological Speciation in Blind Mole Rats: Integration of Thermal Biology and Bite Force in the Upper Galilee Blind Mole Rat ( Nannospalax galili )

ABSTRACT

Ecological speciation refers to the process in which divergent natural selection drives lineage diversification within a species. The Upper Galilee blind mole rat ( Nannospalax galili ) provides a compelling model for studying ecological speciation because it inhabits a landscape lacking physical barriers yet characterized by a stark ecological contrast between rendzina and basaltic soils in northern Israel. These soils differ in multiple biologically relevant properties that strongly influence mole rat biology. Here, we examined differences in energetics and bite force in mole rats from basaltic and rendzina soils to assess whether such differences might contribute to local adaptation and facilitate ecological speciation. We found no population‐level differences in resting metabolic rate, digging metabolic rate, body heat dissipation patterns, or bite force. In contrast, basalt‐dwelling mole rats maintained approximately 1.6°C lower body temperatures than rendzina‐dwelling counterparts, exhibited a larger post‐digging increase in body temperature after burrowing in either soil type, and showed higher digging efficiency. These physiological differences are consistent with the dual challenges of basaltic soil, namely its higher mechanical resistance to digging and the seasonally more hypoxic, CO ₂ ‐rich atmosphere within its burrows. Collectively, our results support a scenario in which thermal and hypoxia‐related physiological traits underpin local adaptations and may contribute to ecological speciation of blind mole rats across contrasting soil habitats.