ANTARCTIC FAUNA.
Mammals.
White.
Antarctic White Seal (_Lobodon carcinophaga_), in some cases.
Changing with the Seasons.
None.
Coloured.
Other Seals than _Lobodon._
Whales.
Birds.
White.
Sheathbill.
Snowy Petrel.
Giant Petrel (some individuals).
Chick of Emperor Penguin.
Changing with the Seasons.
None.
Coloured.
Penguins.
Cormorant.
Skua Gull.
Giant Petrel (usually).
Other Petrels.
It will be observed that the third column contains the largest number of
forms. It is thus evident that the whiteness of the Arctic and Antarctic
faunas in winter has been greatly exaggerated.
The Arctic fox appears in all three columns, as the creature seems to
fall into three races—a permanently white race, a permanently coloured
race, and a seasonally dimorphic race.
Of the creatures set forth in the middle column of the above tables all
are whiter in winter than in summer with the exception of the snow
bunting, who sets at naught the theory of cryptic colouring by turning
darker in winter! The same may be said of the Alpine chamois.
The advocates of the theory of protective colouring assert that the
creatures which do not turn white in winter are strong and active animals
which have no enemies to fear.
This contention is met by F. C. Selous as follows (_African Nature Notes
and Reminiscences_, p. 9): “According to the experience of Arctic
travellers, large numbers of young musk oxen are annually killed by
wolves. . . . Nothing, I think, is more certain than that a far smaller
percentage of so-called protectively coloured giraffes are killed
annually by lions in Africa than of musk oxen by wolves in Arctic
America.”
Another difficulty which confronts the Neo-Wallaceian school is that, _ex
hypothesi_, the assumption of the white coat was gradual. Hence the
change in the direction of whiteness cannot, in its first beginning, have
been of perceptible utility to an organism. How then can natural
selection have operated on it?
Pelagic Organisms
The transparency of pelagic organisms is frequently cited as exemplifying
cryptic colouring. We all know that the common jelly-fish is as
transparent as glass. Floating on the surface of the ocean are millions
of tiny organisms, so transparent as to be invisible to the human eye. At
first sight this certainly appears to be a remarkable case of protective
colouring. Unfortunately, nearly all the more highly developed forms
display conspicuous pigment (as in most jelly-fish) in some part of the
body.
Public-domain text, read in full here on John Shaqi.
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