I think that all life is sacred and has a right to exist. As humans within the web of life, we have tremendous influence to affect other species in our environment. Therefore, it's our responsibility to look after our fellow creatures and protect their habitat. Unfortunately, many domestic animals are feral and homeless, victims of overpopulation who suffer needlessly. A number of organizations are trying to ameliorate this problem and will continue to work against severe odds to help these creatures. There are long standing animal groups such as the Humane Society and SPCA along with new, feral cat coalitions who help to spay and neuter feral cat populations. I recently learned of new "no kill" animal shelters and will list those when their web sites become available.
The situation for certain species of animals is dire. Gorillas, tigers, chimpanzees, rhinos and others are in danger of extinction caused by poaching and habitat destruction.