Birds and Birding's Guide to:

Watching THE PENGUINS

Blue Penguin

As regards size there is considerable range, from the Blue Penguin (Eudyptula minor) of Australia and New Zealand, which is only about sixteen inches in length, to the Emperor Penguin (Aptenodytesforsteri) of the shores of the Antarctic continent, which has a length of forty-eight inches and a weight, according to Ross, Nordenskiold, and others, of sixty to seventy-eight pounds. The length of the various species is between sixteen and forty-eight inches, the average being about thirty inches.

That the Penguins represent a group of great antiquity is shown by the discovery of numerous fossil remains as well as by the apparently primitive character of certain structural elements. The oldest known fossil form (Palaeudyptes antarcticus) is found in the Eocene of New Zealand, and according to Hector, was of gigantic size, standing between six and seven feet in height, although other authorities would make it no more than five feet. In any event it was considerably larger than the largest living species, and it had a proportionately longer wing, yet all of the important skeletal modifications had been already acquired.

Within the past few years, thanks largely to the revival of Antarctic exploration, no less than thirty-one nominal fossil species belonging to nineteen genera have been described, of which number five genera and species were obtained by the Swedish South Polar Expedition on Seymour Island only about two degrees below the Antarctic Circle, and the remainder by Dr. Florentino Ameghino in Patagonia, all, it is believed, in beds of Miocene age.1 These remains have been studied by Drs. Wiman and Ameghino with the astonishing result of showing apparently that the earlier forms of Penguins, so far as shown by their limbs and especially by the tarsi, were much more generalized than the living species.

The tarsi, while comparatively longer in the fossil species than in the living forms, had their component bones much less clearly indicated than in modern Penguins, which is exactly the opposite of what should prevail, if, as has been supposed, the tarsus of the living Penguin is a survival of the primitive free condition of these bones. In other words, it appears that the present-day Penguins, with their uniquely free tarsal bones, have been derived from forms in which these bones were more or less consolidated, which naturally brings them closer to ordinary carinate birds in which the tarsal bones are practically solid.

This consolidation of the tarsal bones is possibly an adaptive feature which has perhaps been brought about”by the habit of sitting with the tarsus on the ground when at rest."

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