Possibly related to this, Númenor had a lot of foxes, and some of the animals of Númenor had some level of intelligence
In c.1965 Tolkien wrote an essay called "Of the Lands and Beasts of Númenor". Portions of this essay were published in Unfinished Tales, and the remainder of it was recently published in The Nature of Middle-earth.
In this essay Tolkien discusses the fauna of Númenor and focuses a bit on how there were many foxes in Númenor, which helped to control their rabbit population and got along well with the Númenóreans.
As for the major animals, it is clear that there were none of the canine or related kinds. There were certainly no hounds or dogs (all of which were imported). There were no wolves. There were wild cats, the most hostile and untameable of the animals; but no large felines. There were a great number, however, of foxes, or related animals. Their chief food seems to have been animals which the Númenóreans called lopoldi. These existed in large numbers and multiplied swiftly, and were voracious herbivores; so that the foxes were esteemed as the best and most natural way of keeping them in order, and foxes were seldom hunted or molested. In return, or because their food-supply was otherwise abundant, the foxes seem never to have acquired the habit of preying upon the domestic fowl of the Númenóreans. The lopoldi would appear to have been rabbits, animals which had been quite unknown before in the north-western
regions of Middle-earth. The Númenóreans did not esteem them as food and were content to leave them to the foxes.
The Nature of Middle-earth - "Of the Land and Beasts of Númenor"
While none of this by itself indicates intelligence, the paragraph immediately after this one talks about bears, and they seem pretty intelligent.
...The relations of the bears and Men were strange. From the first the bears exhibited friendship and curiosity towards the newcomers; and these feelings were returned. ... Very few Númenóreans were ever killed by bears; and these mishaps were not regarded as reasons for war upon the whole race. Many of the bears were quite tame. They never dwelt in or near the homes of Men, but they would often visit them, in the casual manner of one householder calling upon another. At such times they were often offered honey, to their delight. ... At times the bears would perform dances for the entertainment of their human friends. ... To those not accustomed to the bears the slow (but dignified) motions of the bears, sometimes as many as 50 or more together, appeared astonishing and comic. But it was understood by all admitted to the spectacle that there should be no open laughter. The laughter of Men was a sound that the bears could not understand: it alarmed and angered them.
The Nature of Middle-earth - "Of the Land and Beasts of Númenor"
And then the paragraph after that discusses squirrels, also with somewhat similar terms:
The woods of Númenor abounded in squirrels, mostly red, but some dark brown or black. These were all unafraid, and readily tamed. The women of Númenor were specially fond of them. Often they would live in trees near a homestead, and would come when invited into the house.
The Nature of Middle-earth - "Of the Land and Beasts of Númenor"
It seems that there may be a theme above Númenor's animals being intelligent, including their foxes, and perhaps that is related to this fox.