- "A sort of elephant." "With a trunk?" "Yes. Hairy all over." "Horrible?" ... "No. Gorgeous," said Titty hurriedly. (Titty and Bridget, SW7)
- "Don's as good a short for Mastodon as it is for Donald" (Daisy, SW20)
The Mastodon, actual name Don, is a member of a savage tribe, the Eels, and lives on Speedy, the hulk of a barge, half swallowed by the mud, in a creek between Mastodon Island (adjacent to Swallow Island) and the mainland. He says I've got to nip across to Speedy before starting home (SW12).
Don says that I was born here and that Mother gave me a ham .... (SW15). When told that the Swallows call the farmhouse a Native Kraal, he says that Kraal's a good word. My father's got a kraal too. Over there. He pointed south over the marshes (SW8). He leaves a sack of food for them with the Witch at Witch's Quay. who says to them Looking for young Don? though the relationship (if any) of her to Don and his family is not stated (SW14).
- The Swallows and the Amazons meet the Mastodon in Secret Water. His splatchers leave big round marks on the mud, which Titty thinks are the marks of a Mastodon (a mammoth-like creature). When they meet him, and learn that his name is Don, Titty insists that this is short for Mastodon (SW8).
Mastodons feature in A Journey to the Centre of the Earth, a classic 1864 science fiction novel by Jules Verne. Titty and Dorothea have both read this book. When they go down the tunnel to consult Slater Bob, they hear a thudding noise. Dorothea asks Have you read "A Journey to the Centre of the Earth"? Titty replies About Hans Stek and the hot water spouting out of the rock? and Dorothea says About the mastodons ... it's a whole herd of them stamping (PP3).