Yes, you can. This sentence makes sense.

The sentence is certainly correct. However, infinitives would work better than present participles ("to save animals is to save ourselves") because of the factual nature of the sentence. Participles work best for describing things whereas infinitives work best for expressing truths. It is for that reason that Shakespeare wrote: "To be or not to be, that is the question" rather than "Being or not being, that is the question". It would have been equally correct but it would not have sounded nearly as good.

Sure