The ultimate question? Why do dogs...?

If the answer to the ultimate question:

What it is the meaning of life equates to 42 then

...why do dogs chase

...and the answer is "PffStt".

Think about it!
Catch a cat and take a chomp and it goes pffstt, pffsst, pffsst.

Catch car tyre and ...

Simple questions sometimes require simple answers.
Why spend life looking for difficulties?