it's actually a relatively understood phenomenon. it's not really that the tiger is lonely, tigers do tend to live alone in the wild, and more that dropping a goat in plain sight isn't setting off it's instincts to hunt. further, tigers are advanced mammals and consequently relatively smart creatures - it no doubt was able to compute that the stream of food was constant. so, you put those things together and what you get is something more along the lines of the idea that the tiger is *bored*.
but, it only explains half of the issue. i have somewhat of a hunch that the tiger may soon try and mate with the goat. that might be what's actually going on.
www.theweathernetwork.com/news/articles/tiger-and-his-prey-form-an-unlikely-friendship/62466/