Robert Graves remarked in his book, Goodbye to All That: "Rats came up from the canal, fed on the plentiful corpses, and multiplied exceedingly. While I stayed here with the Welch. a new officer joined the company and, in token of welcome, was given a dug-out containing a spring-bed. When he turned in that night he heard a scuffling, shone his torch on the bed, and found two rats on his blanket tussling for the possession of a severed hand."
Many men killed in the trenches were buried almost where they fell. If a trench subsided, or new trenches or dugouts were needed, large numbers of decomposing bodies would be found just below the surface. These corpses, as well as the food scraps that littered the trenches, attracted rats.
These rats became very bold and would attempt to take food from the pockets of sleeping men. Two or three rats would always be found on a dead body. They usually went for the eyes first and then they burrowed their way right into the corpse.
https://spartacus-educational.com/FWWrats.htm
Amazon.com reports: Robert Graves' superb autobiography tells the story of his life at public school and as a young officer during the First World War. 'It is a permanently valuable work of literary art, and indispensable for the historian either of the First World War or of modern English poetry...
Good-Bye to All That, an autobiography by Robert Graves, first appeared in print in 1929.
https://en.wikipedia.org/wiki/Goodbye_to_all_that
