Translation:The stupid weasels try to grab the mice.
Indeed, Latin was one of the inspirations of Esperanto, which takes its vocabulary from the Romance languages, all Latin derivatives.
I find it amusing that Esperanto was meant to be taught to students in a few short months. And here we are, learning the original lingua franca, the tongue of the Roman Empire, on an apparently similar time scale despite its supposed difficulty.
They intend us to use the phrase "try to grab" for captant, every time.
To my surprise, since I checked to see if there was another choice for captant, they didn't accept "snatch at", though that was one of the 'hover' prompts.
I guess the weasels will "try to grab" the mice, for all eternity!
It's the meaning given in Lewis & Short, and Gaffiot, so I think the course authors are right. But the vocabulary is really always the same in these lessons. Introducing the vocabulary step by step, yes, but it gets very repetitive: parrot, drunk, plurimi, captare, mustela, forum.
Always the same stuff, but combined differently in every sentences.
Gaffiot says " chercher à prendre, chercher à saisir, chercher à prendre, chercher à attraper", so it means they try and they fail, or that they are still in the action of trying.
A better example than "mice" would have been "flies", or maybe, figuratively "the truth".
Lewis says it's chasing, to strive to seize, etc...
Snatching, with the definition "to try to take hold of something" seems also correct.