"Various animals are drinking the water."
Translation:Verschillende dieren drinken het water.
Verschillende dieren drinken het water.
Verschillende dieren zijn het water aan het drinken.
If you want to use zijn here, you need to combine it with aan het +(infinitive verb). The resulting sentence would then be in the present continuous, which (in Dutch) is used to talk about something that is happening right now.
Imagine that you were camping somewhere in nature and you had collected rain water to be able to brush your teeth, etc. You then decide to sit under a tree and relax and you doze off, but then your friend wakes you up 'you forgot to cover the bucket and those animals are drinking the water, you bloody fool!!!'
That coincides with one of the uses we have for this tense in English (although in English we use it for other things as well).
Sorry if there are any typos: I'm bad at typing, I have a mild form of dyslexia, and there's no edit button on the app. I've tried not to screw up, but I cannot be sure this is 100% error free (I've already retyped the entire post two times, so I'm quite fed up with it).