1961 Volume 3 Issue 2 Pages 126-128
The stomach stones found packed in the proventriculus of two young Adelie Penguins, brought from Japanese "Showa" Antarctic Base, are reported. The number and species of stones contained in proventriculus A were 26 Biotite Gneiss pieces, 6 Aphite pieces and 1 small Feldspar, with some tiny pebbles and B contained 25 Biotite Gneiss, 13 Aphite and 1 Amphipolite, with some small peblles (Table 2).
The larger stones were size of finger head, weighing more than 1gr. to even 5.9gr. (Table 1), and their total weights were 54gr. (A) and 21.5gr. (B).
Such stones in the proventriculus are not same functionally as usual stomach stones found in the gizzard of other birds. Judging from literture on the Emperor Penguin, they were apparently fed by parent and the function of giving weight for deep diving may not be rejected at once until other function becomes clear.