Musnad Abu Ya'la al-Mawsili 108:188

Amr al-Naqid narrated to us, Sufyan ibn Uyaynah narrated to us, from Amr, from Jabir ibn Abdullah, who says: The Messenger of Allah (ﷺ) sent us out in a group of three hundred riders, and our commander was Abu Ubaydah ibn al-Jarrah, to lie in wait for a caravan of Quraysh. We stayed on the coast for half a month, and severe hunger afflicted us until we ate the *khabt* (leaves of trees). He said: So that army was named the Army of the *Khabt*. Then the sea cast out for us a creature called the *Anbar* (ambergris/whale). We ate from it for half a month until our bodies recovered and we anointed ourselves with its fat. Abu Ubaydah took one of its ribs and looked at the tallest camel in the army, and he had it carried upon it, and it passed underneath it.