Who saw the otter?

May 9. 

Another fine day. 

6 a. m. — On water. 

Maryland yellow-throat. Aspen leaves one inch over.

Hear stake-driver. Black and white creeper's fine note. Er-te-ter-twee, or evergreen-forest note. Golden-crowned thrush note. Kingbird. 

P. M. To Gilson's Mill, Littleton. 

George Brooks points to an old house of which one half the roof only has been shingled, etc., etc., and says he guessed it to be a widow's dower from this, and on inquiry found it so. 

Went to Gilson's tumble-down mill and house. He appeared, licking his chaps after dinner, in a mealy coat, and suddenly asked in the midst of a sentence, with a shrug of his shoulders, 

"Isn't there something painted on my back ?" 

There were some marks in red chalk they used to chalk the bags with, and he said he thought he had felt his son at the mill chalking his back. He feared he was making an exhibition before strangers. 

The boy speared fishes, chiefly suckers, pouts, etc. A fire in a hand-crate carried along the bank of the brook (Stony Brook). He had lately speared a sucker weighing five and a quarter pounds, which he sold; went back and forth some twenty-five rods and found the suckers less shy at last than at first. 

Saw otter there. 

I saw many perch at the foot of the falls. 

He said that they and trout could get up five or six feet over the rocks there into the pond, it being a much broken fall.

H. D. Thoreau, Journal, May 9, 1857

Saw otter there. Consider. Did Thoreau, while visiting the falls at Littleton, see an otter? Or is he recounting a second-hand story about Gilson the miller's son? See March 31, 1857 ("The existence of the otter, our largest wild animal, is not betrayed to any of our senses (or at least not to more than one in a thousand)!"); April 6, 1855 ("it reminds me of an otter, which however I have never seen."); February 20, 1855 (among the quadrupeds of Concord, the otter is "very rare."); January 30, 1854 ("How retired an otter manages to live! He grows to be four feet long without any mortal getting a glimpse of him,");  January 21, 1853 ("Otter are very rare here now.”); and the Natural History of Massachusetts (1842) ("The bear, wolf, lynx, wildcat, deer, beaver, and marten have disappeared ; the otter is rarely if ever seen here at present; and the mink is less common than formerly..")