do you think that animals without a sexual parter withwhich to mate are emotionally frustrated? is it cruel to keep a frog without a mate in a pond, hypothetically?

I don't know! With the loss of habitat and animals in the wild today, sometimes animals naturally can't find a mate. For birds and mammals, this often makes them lose a zest for life but frogs probably aren't as bothered. Males would just call and maybe feel sad that nobody comes. Females only problem would be possible egg-binding if they produce eggs but can't lay them.

I do not think animals are nearly as emotional as humans, however I do believe problems can occur when there is no mate present. Think outside the box (away from “sexual frustrations”) and think about what humans do and act like without a partner... in the long term. To keep things PG, there are other problems associated with this in humans, besides the (often over-hyped) stereotypes.