Marks beside the reed bed

An original account of an invented wildlife survey.

At first light, our survey group followed the narrow path beside the reed bed. Overnight rain had softened the mud, leaving it crowded with marks from boots, bicycle tyres and birds. Near the water, Mina stopped beside a print that none of us had noticed.

She measured it, photographed it and opened her notebook. The shape suggested that an otter might have crossed the path, but one edge had been washed away. Mina made a tentative identification, adding a question mark beside the animal's name. Further along the bank, we found a clearer set of prints with the same shape. Only then did she return to her first note and remove the question mark.

In this passage, what does “tentative” mean?