What do we know about continence in animals? In particular, what do we know about the development of continence in animals?
By "continence", I'm referring specifically to whether or not a wild animal, free from human influences, appears to exhibit discrimination in when and where it relieves itself, and to what extent. For example, rats are allegedly incontinent, at least by this definition. (The article would seem to imply they are physically unable to control themselves, but other sources state that rodents can learn continence, which would imply that they normally just don't bother, which is what I want to know about.) Conversely, cats can be quite fastidious, and kittens are reportedly "unable" to void themselves without their mother's assistance. In fiction, we have an example of a species which is said to uncontrollably void when they eat.
Based on what we know from studying real animals, is it plausible that an animal would be unable to control its voiding out of a habit of not trying to do so (I'm ignoring physical problems, here), or is the cited source, if you'll excuse the highly apropos expression, full of sh--? If it is plausible, what types of animals, generally speaking, would exhibit this, and to what extent? Also, how does this change from birth to maturity?
Ultimately, what I am looking for is a set of guidelines that would allow me to predict an animal's voiding habits and the extent to which the animal is able to control the same given the animal's age/maturity and other general information (e.g. dietary tendencies). I am not worried about outliers, unless the answer is that it is not possible to make a prediction with any reasonably accuracy, in which case I would still like to know what range of variation I might expect.
Edit: I'm increasingly suspect of the cited source on rats. If that's bunk, I would still like to know; are there any examples of animals (perhaps excluding humans, because that can turn into quite the argument) who, at any life stage, do not exhibit continence and/or exhibit feline-like "hyper-continence" (i.e. inability, or at least instinctive disinclination, to void on their own) absent physiological abnormalities? (Alternatively, am I also wrong about cats?)