I have this day been painting a portrait of the head chief of the [Blood tribe] he is a good-looking and dignified Indian, about fifty years of age, and superbly dressed; whilst sitting for his picture he has been surrounded by his own braves and warriors and also gazed at by his enemies, the Crows and the Knisteneaux, Assinneboins and Ojibbeways; a number of distinguished personages of each of which tribes have laid all day around the sides of my room; reciting to each other the battles they have fought, and pointing to the scalp-locks, worn as proofs of their victories, and attached to the seams of their shirts and leggings.
The name of this dignitary of whom I have just spoken is S tu-mick-o-sucks (the buffalo's back fat), i.e., the hump or fleece the most delicious part of the buffalo's flesh. The dress of the chief consists of a shirt or tunic, made of two deerskins finely dressed, and so placed together with the necks of the skins downwards, and the skins of the hind legs stitched together, the seams running down on each arm, from the neck to the knuckles of the hand; this seam is covered with a band of two inches in width, of very beautiful embroidery of porcupine quills, and suspended from the under edge of this, from the shoulders to the hands, is a fringe of the locks of black hair, which he has taken from the heads of victims slain by his own hand in battle. In his hand he holds a very beautiful pipe, the stem of which is four or five feet long, and two inches wide, curiously wound with braids of the porcupine quills of various colours; and the bowl of the pipe ingeniously carved by himself from a piece of red steatite of an interesting character, and which they all tell me is procured somewhere between this place and the Falls of St. Anthony, on the head waters of the Mississippi (Letters and Notes, vol. 1, pp. 2931, pl. 11).
Painted at Fort Union in 1832. Catlin believed that in the Blackfoot and Crow tribes he had at last found the perfection of aboriginal life, and his month-long visit to the mouth of the Yellowstone was perhaps the most satisfying and productive time of his western travels. In full command of his craft, and inspired by the rich costumes and splendid physical appearance of his subjects, he painted some of his finest portraits, and one that may well rank as his masterpiece, Buffalo Bull's Back Fat. Broadly yet firmly modeled, with incisive detail and bold color, the portrait is as accomplished as any painted on the Missouri River voyage. But more compelling is Catlin's measure of the impassive, brooding stare of the chief, who seems perplexed and challenged, in spite of his imposing appearance, by the unfamiliar circumstances in which he finds himself.
Catlin must also have recognized the importance of the work, as it was one of two he entered in the Salon of 1846, perhaps after some additional finishing. Both paintings made a lasting impression on Baudelaire, who praised the noble and spirited character of the Indians, and the primitive strength of Catlin's reds and greens (see Beetem). Ewers (1949) compares the portrait to Karl Bodmer's watercolor of the same subject (illustrated here), in which the features are recorded with extreme detail. Catlin's work seems accurate enough by comparison and conveys a far greater range of drama and insight.
Buffalo Bull's Back Fat becomes a full-length seated figure in plate 11 of Letters and Notes and cartoon 39. He is accompanied by his wife and a Blackfoot medicine man in the latter.