THE PENGUINS OF SOUTH GEORGIA 227 
now, with the fluctuating seasons, the 
glaciers sometimes advance their fronts 
and flanks over considerable ground 
once abandoned, but in general glacia- 
tion is on the wane, and an appreciable 
decline has taken place even within a 
century. From such a condition it may 
be assumed that for a long period follow- 
ing the last ice-cap very little territory 
suitable for breeding purposes was ex- 
posed. Whatever bare earth existed 
must have been found along the ridges 
which separated the ice-filled valleys. 
During such a period these small pen- 
guins may have developed the trait 
which still leads them to seek lofty places 
for their nests. The fact that South 
Georgia was formerly the home of a far 
more abundant fauna than at present 
would have tended to fix the “moun- 
taineering”’ instinct, for animals ob- 
taining 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 be 
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 king penguins. 
The faith which the Johnny penguins 
hold in the protectiveness of high land 
is strangely shown by their habit of 
running away from the water whenever 
danger threatens. Their terrible ma- 
rine enemy, the sea-leopard, a large 
carnivorous seal, has fixed within the 
Johnnies an instinct which urges them. 
to seek safety only on terra firma. Con- 
sequently they do not govern their acts 
according to their perceptions. Time 
and again I have seen a group of them 
standing at the water’s edge when a fox 
terrier, brought ashore from the vessel, 
started toward them at a run. If the 
penguins deigned to show any fear at 
the approach of the barking dog they 
invariably responded not by taking to 
the water, where they would have been 
rid immediately of the tormentor, but 
by deliberately running up the beach, 
heading for the nearest bank or hillside. 
Even after the dog had seized a penguin 
by its bristly tail and had swung it 
round and round merely for the fun of 
At a rookery of Johnnies 
