Yes it can. And in Kaleb's case, effort is a measurement of the length of the tongue. And as you can see he always gives 110%.
Note the lack of tongue on the subject to the left. It is safe to assume the subject on the right did most of the work.
There is nothing better in the world seeing a working dog work, doing what they were bred to do. Nothing tops it. Well except for having a really good weekend at an Agility Trial :) that is a close second.
*editors note: you must think he consumes alot of water hunting? You're right, I would say 2 or 3 litres ... and someone has to carry it ... my name is Sarah, I am a pack mule ...