ADAPTATION TO CIRCUMSTANCES. 41 
has several duplicate sets in each jaw, previous to starting Puff 
Adder or Cobra taming experiments. 
ADAPTATION TO SURROUNDINGS. 
Adaptation of habits and colouration to surroundings is 
possessed in greater or lesser degree by all living creatures. This 
provision of Nature operates in two ways. It serves as a pro- 
tection against enemies. On the other hand, it is of immense 
service to flesh-eating animals in capturing their prey. The 
tree-climbing snakes are so alike in colouration to the branches 
and foliage that they have little difficulty in getting within 
striking distance of birds. I have seen Tree-snakes remain per- 
fectly rigid, twisting their bodies to represent tree branches, and 
have watched birds hop right up to them, and even perch upon 
their bodies, mistaking them for twigs. A bird once within 
striking distance of a Tree Snake has very little chance of escape, 
so rapid are the snake’s movements. I have seen Boomslangs 
and Green Mambas make off into small trees scantily clothed 
with leaves and instantly vanish from sight. On close inspection, 
they would be found to be entwined among the branches, rigid 
and still, relying upon the blending of their colouration with 
their surroundings to escape detection. 
The colour of nearly all snakes blends with their surroundings. 
A Puff Adder, for instance, lying upon the leaf and twig-strewn 
earth is practically invisible to any one not specially on the look- 
out for it. 
In the various parts of South Africa snakes of the same 
species vary more or less in colour to suit the nature of their 
surroundings. The natural habitat of the Boomslang is in trees 
and shrubs. Its body is, therefore, specially evolved for climb- 
ing and rapid gliding movements through dense foliage. In the 
Eastern Province of the Cape Colony I have frequently seen and 
captured Boomslangs of a chocolate-brown colour on the ground. 
When alarmed they invariably glide off and seek refuge down 
holes, among refuse, or shrubs. I have not yet discovered them 
in trees. 
Mr. James Williams, the man who captures snakes for me, 
tells me that he nearly always finds these chocolate-coloured 
