Il6 BROrjKLVN INSTITl'TE JH-SEl'IM. SCIEXCK Bn.LKTIX 2. 5- 
fulliiwiiii;- the last ci)ni])lete tjlaciation, \-er\' little territory suitaljle for 
breeding purjioses was exposed. Whatever bare earth existed must have 
been found along the ridges which separated the ice-filled valle\s. During 
such a period, before the parent stem of the Pygoscelis grou]i had been 
differentiated into several species, these small penguins may have 
developed the trait which still leads them to seek lofty places for their 
nests. The fact that South Georgia was formerl}- the home of a far more 
abundant fauna than at i)resent would have tended to fix the ' ' mountain- 
eering " instinct, for animals obtaining their sustenance only in the sea 
would have a tendency to increase more rapidly than the proportionate 
area of the beaches, and through sheer overflow of population many birds 
would l)e forced to content themselves with the less accessible ground, 
leaving the shores to great herds of summering seals,* and the adjacent 
nesting-sites to powerful rivals such as the Aptcnodytes penguins. Then 
there is the factor of floods, whether catised b^- excessive thaws or by 
exceptional titles im]ielle(l li\ storms. At the Bay of Isles I found not 
only masses of kelp but also the hea\\- skull of a killer whale ( Ona) far 
back on the great moraine-beach where it .seemed almost incredible that 
the sea could have carried them. Becau.se of the elevation of their nests 
the Pygoscelis penguins are more secure against floods than the Aptcnodytes. 
Possibly this accounts in part for the greater numerical strength of the 
former, for although Pygoscelis la>-s one more egg than its larger relative, 
the king i)enguin's single offs]iring seldom if ever becomes the ])re\- of the 
skua, which I'laxs such havoc among the rookeries of the johnnies. 
The hypothesis which I have advanced would be as a]3i)licable to any 
other austral region as to South Georgia, for the .same physiographic and 
biological conditions have doubtless obtained throughout a wide circum- 
polar belt. 
The faitli which the jolinnx' jienguins hold in the ])rotectiveness of 
high land is strangely shown li\- their haliit of running away from the 
water whene\-er danger threatens. Their enem_\-, the sea leo]iard. has 
fixed within them an instinct which urges them to seek safet\- only on 
terra Jini/a. Consequently they do not govern their acts according to 
their jierceptions. Time and again I have seen a .group of them standing 
at the water's edge when a fox terrier, brought ashore from the Daisy. 
started toward them at a nui. If the iienguins deigned to show any fear 
* .\t South 
Oeomia I hav 
e seen .sea elephants i 
.Vi,o„„t;iih 
■11)11 iia\ 
1 drag themselves 
rater that tl 
-ookerv. 
hey Ijecaine a I 
ilind menace to johni; 
ly penguin i 
i,estso 
u low ground at 
