An Ottsel is a creature combination of an Otter and a Weasel. They have Redish-Orange fur with Light yellow bellies. Precursors are infact Ottsels, which could mean that they are sentinent creatures.
It seems that Ottsels, the way they are spoken of, could also just in fact be wild creatures as well. However, it would make little sense if only some ottsels are Precursors and others are not, but it is possible that the Precursors created a subspecies of ottsel to cover the fact that they were the very rats themselves. This would explain the difference between the Precursor Ottsels and Daxter. They could also be regular animals turned into Ottsels by Eco, like Daxter. If so, they would also have their original level of inteligence, also similar to Daxter's case. Another theory is that in order for Ottsels to achieve Precursor status they have to undergo a procedure simular to that of Young Samos in Jak II to become a sage.
Technobliterator also made an ottsel later, but made the page on this wiki first