Tangs in a 90?

[Samw]

If we are going to use territory to estimate the space needed for a fish, why aren't we doing that for every animal? How much space would a wild dog or horse need? In the wild, their territory span miles I'm sure. Yet, there are hundreds or thousands of dog owners in downtown Vancouver keeping dogs in their condo. Yet, the SPCA does nothing about it. Horses are kept in small fields. What about rats? Isn't a cage too small for a rat? What about birds? Isn't a cage too small for a bird? What's the minimize size of cage for a bird? Why do some many people keep these animals in spaces much smaller than their normal territory size? Those examples seem more cruel yet for some reason, people make more noise over a fish in a 90G tank.