I know that dogs were used in WW1. I know that they weren’t vital, but didn’t play a reasonable role in helping the soldiers in the trenches. However, there is one thing that confuses me: How were dogs used to aid in communication in the trenches? Such a task of getting them to deliver a symbol would take intense time wasting training. Something that can be invested in troop training. Other than communication, there only other uses were carrying equipment (not vital) and as a physiological comfort. Does anybody have any-more uses?
Yup. Although not vital to the war, they were useful.
First, WW1 was the first war to use chemical weapons. Due to dogs superior sense of smell, they could smell oncoming gas attacks and and alert their handlers, thus minimizing the effect of the poison gas before gas masks could be donned.
Another use was guarding. This was not really specific to WW1. Dogs have been used to guard camps and to alert handlers of oncoming troops for centuries.
As far as communication, dogs would have to be dedicated to two handlers instead of just one. This was difficult, yet necessary to get a dog to travel immediately and directly to the second handler upon release. However, dogs that were trained to do this were much quicker than humans, presented smaller targets, were able to go over almost any terrain, and were generally reliable. This made their use for communication useful in some circumstances, but definitely not the primary means of communication.
Dogs were also used for locating injured men in no-man's land by their scent and sound.
Finally, dogs were sometimes used to draw machine guns, but this was not widespread do to the unconventionalism of it.
As a final note, some dogs could hear shells before humans could. They would then alert their handlers. However, I only found this on one Wikipedia page and it was unsourced, so I would take it with a grain of salt.
And, yes, dogs were also used as mascots.