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Updated: May 2, 2026

A Modified Mirror Test as a Visual Guide for the Self-awareness Trait in Wild Antarctica Penguins, Pygoscelis adeliae
Published on: July 8, 2025
[The geese who flew home for Christmas]
1Klinisk Fysiologisk/Nuklearmedicinsk Sektion, Afsnit 239, Hvidovre Hospital, Kettegård Alle 30, 2650 Hvidovre. jens.henrik.henriksen@regionh.dk
Abstract:
Gray geese of the bar-headed type (Anser indicus synonym: Eulabeia indica) perform trans-Himalayan migratory flight at extreme altitude. The physiological mechanisms include hyperventilation of cold air, increased lung diffusion capacity, proton gradients, high muscular temperature, amino acid mutation in haemoglobin and cytochrome oxidase, re-location of mitochondria, and extreme shifts in the oxy-haemoglobin dissociation curve due to Bohr- and temperature effects. The second annual migration takes place in late autumn, and the bar-headed geese come home in due time before Christmas.
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