وَعَنْ عَامِرِ بْنِ رَبِيعَةَ رضى الله عنه
قَالَ: «رَأَيْتُ رَسُولَ اَللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ (يُصَلِّي عَلَى رَاحِلَتِهِ حَيْثُ تَوَجَّهَتْ بِهِ»
I saw the Messenger of Allah (sallallahu alayhi wa sallam) praying while mounted on his riding animal facing whatever direction it faced.
Bulugh al-Maram 253, Book 2, The Book of Prayer, Hadith 74. 1 min read