Shipton's Yeti Photos at Auction

From the Telegraph:

"Four photographs of large paw prints in the snow beneath Mount Everest are to be sold at Christie's in London on September 26.
"The images were taken by the legendary British mountaineer Eric Shipton on a reconaissance trip to Everest in 1951..."
"Tom Bourdillon, who was also in the reconaissance party, later gave Shipton's black and white prints, which measure 6ins by 4ins, to a friend, Michael Davies.
"Mr Davies' descendants are now selling the historic souvenirs, which are expected to fetch £2,500." ...
"On the back of one of his images, Bourdillon wrote to Davies about the team's sighting of the prints.
"He said: 'We came across them on a high path on the Nepal-Tibet watershed during the 1951 Everest expedition.
"'They seem to have come over a secondary path at about 19,500ft down to 19,000ft where we first saw them and then went on down the glazier.
"'We followed them for the better part of a mile. What it is I don’t know, but I am quite clear that it is no animal known to live in the Himalaya and that it is big.'"

The estimate sounds a bit on the high side...