The Nez Perces, the Flatheads, and the Hanging-ears pride themselves
upon the number of their horses, of which they possess more in
proportion than any other of the mountain tribes within the buffalo
range. Many of the Indian warriors and hunters encamped around Captain
Bonneville possess from thirty to forty horses each. Their horses are
stout, well-built ponies, of great wind, and capable of enduring the
severest hardship and fatigue. The swiftest of them, however, are those
obtained from the whites while sufficiently young to become acclimated
and inured to the rough service of the mountains.

By degrees the populousness of this encampment began to produce its
inconveniences. The immense droves of horses owned by the Indians
consumed the herbage of the surrounding hills; while to drive them to
any distant pasturage, in a neighborhood abounding with lurking and
deadly enemies, would be to endanger the loss both of man and beast.
Game, too, began to grow scarce. It was soon hunted and frightened out
of the vicinity, and though the Indians made a wide circuit through
the mountains in the hope of driving the buffalo toward the cantonment,
their expedition was unsuccessful. It was plain that so large a party
could not subsist themselves there, nor in any one place throughout the
winter. Captain Bonneville, therefore, altered his whole arrangements.
He detached fifty men toward the south to winter upon Snake River, and
to trap about its waters in the spring, with orders to rejoin him in the
month of July at Horse Creek, in Green River Valley, which he had fixed
upon as the general rendezvous of his company for the ensuing year.

Of all his late party, he now retained with him merely a small number of
free trappers, with whom he intended to sojourn among the Nez Perces and
Flatheads, and adopt the Indian mode of moving with the game and grass.