Behavioural responses of naked mole rats to acute hypoxia and anoxia

Naked mole rats (NMRs) are among the most hypoxia-tolerant mammals. Other species respond to hypoxia by either escaping the hypoxic environment or drastically decreasing behavioural activity and body temperature (Tb) to conserve energy. However, NMRs rarely leave their underground burrows, which are putatively hypoxic and thermally stable near the NMRs' preferred Tb. Therefore, we asked whether NMRs are able to employ behavioural and thermoregulatory strategies in response to hypoxia despite their need to remain active and the minimal thermal scope in their burrows. We exposed NMRs to progressively deeper levels of hypoxia (from 21 to 0% O2) while measuring their behaviour and Tb. Behavioural activity decreased 40–60% in hypoxia and Tb decreased slightly in moderate hypoxia (5–9%) and then further with deeper hypoxia (3% O2). However, even at 3% O2 NMRs remained somewhat active and warm, and continued to explore their environment. Remarkably, NMRs were active for greater than 90 s in ac...