DO ANIMALS THINK AND REFLECT? 
for her nest. She hopped to this tangle of shoots and 
sat down, then to that, she turned around, she re- 
adjusted herself, she looked about, she worked her 
feet beneath her, she was slow in making up her 
mind. Did she make up her mind? Did she think, 
compare, weigh? I do not believe it. When she 
found the right conditions, she no doubt felt pleasure 
and satisfaction, and that settled the question. An 
inward, instinctive want was met and satisfied by an 
outward material condition. In the same way the 
hermit crab goes from shell to shell upon the beach, 
seeking one to its liking. Sometimes two crabs fall 
to fighting over a shell that each wants. Can we 
believe that the hermit crab thinks and reasons? It 
selects the suitable shell instinctively, and not by an 
individual act of judgment. Instinct is not always 
inerrant, though it makes fewer mistakes than reason 
does. The red squirrel usually knows how to come 
at the meat in the butternut with the least gnawing, 
but now and then he makes a mistake and strikes the 
edge of the kernel, instead of the flat side. The cliff 
swallow will stick her mud nest under the eaves of a 
barn where the boards are planed so smooth that the 
nest sooner or later is bound to fall. She seems to 
have no judgment in the matter. Her ancestors built 
upon the face of high cliffs, where the mud adhered 
more firmly. 
A wood thrush began a nest in one of my maples, 
as usual making the foundation of dry leaves, bits 
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