Q: I have three ferrets, Stanley, Albert and Beau; all are about 9 months old. Two of them come running when they see my mug of tea. They seem to love it, but I only allow them the last few drops, about a teaspoon. I have read the opinions of some pundits who condemn the very thought of ferrets having lactose and caffeine. Considering my tea contains 2 percent milk and no sugar, do you think it is harmful to them? Their normal diet is a top-quality, propriety ferret food, sometimes a little raw bacon and beef, and a weekly treat of 2 ml olive oil and cod liver oil mixture.
A: In extremely small amounts, lactose and caffeine will probably cause your ferret no harm. But over a lifetime of ingesting this, could you cause a problem? Possibly.
No one has done studies on the safety or toxicity of lactose or caffeine in ferrets over time, so it is difficult to judge if this will cause harm. Without the benefit of data, this is what I consider when I do not have specific studies to consult — are any of these substances part of the normal diet of wild mustelids, especially the closer cousins of ferrets? In the case of caffeine and lactose, likely they are not. So, if the gastrointestinal tract of wild mustelids has not evolved to break down and assimilate caffeine and lactose, we should probably assume the same for our pet ferrets.
Will these unnatural foodstuffs cause a problem now or in the future because they are not a normal part of a ferret’s diet? At this point, we cannot say. But I would rather feed ingredients I know are part of a ferret’s diet than ingredients meant for humans. I would rather feed food that I know the ferret’s gastrointestinal system can easily digest than foods that were designed to be ingested by people.