From Sahih Bukhari (Hadith 1857):
Narrated `Abdullah bin `Abbas:I came riding on my she-ass and had (just) then attained the age of puberty. Allah's Messenger (ﷺ) was praying at Mina. I passed in front of a part of the first row and then dismounted from it, and the animal started grazing. I aligned with the people behind Allah's Messenger (ﷺ) (The sub-narrator added that happened in Mina during the Prophet's Hajjat-al-Wada)
Reference: Bukhari 1857