Can We Teach Animals the Dhamma?
There's a Jakarta story of a previous incarnation of the Buddha giving his body to a hungry tigress. The reason for that act was to prevent the tigress eating her cubs, which would have damaged her sila.


  Therefore, I will kill my miserable body by casting it down into the precipice, and with my corpse I shall preserve the tigress from killing her young ones and the young ones from dying by the teeth of their mother.


My mum rescued a stray dog. She (the dog) was initially aggressive to other dogs, but my mum taught her not to be.
My mum also taught her self-restraint: including to not rush to get her dinner immediately, but to wait when the dinner bowl is set on the floor, wait until she is told that she can get it.

I like to think that you're able to help a dog, for example by teaching it some morality. 

In terms of teaching them Dhamma, although they cannot read books I hope they can read you.