The nasal mite Halarachne halichoeri thrives in a unique niche: the respiratory tracts of deep-diving seals, where it faces high hydrostatic pressures, hypoxia, and osmotic stress. Using synchrotron X-ray microtomography, 3D reconstruction, scanning electron microscopy, and confocal laser scanning microscopy, we reveal the mite’s adaptations to these extreme conditions. Its specialized attachment system, comprising two claws a...