What are the requirements for a valid animal race (musabaqah)?

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The race must define a fixed distance, having agreed-upon start and end points, because the objective is to ascertain who is the swifter. This requires equality in the defined length, as some animals may be slow initially but fast later, or vice versa, necessitating a fixed endpoint to compare both phases of their running. Furthermore, the two horses or camels must be released simultaneously at the starting point. An observer must be present at the start to witness the release and record the initial order, and another must be present at the finish line to precisely determine the winner. Evidence supports that the Prophet, peace be upon him, held races for horses, favoring the trained horse ('al-qarih') in the finish line, as narrated by Ibn Umar and recorded by Abu Dawud. Distances varied: races for trained horses ('al-mudmar') were set between Al-Hafya' and Thaniyyat al-Wada', covering six or seven miles, while races for untrained horses were between Al-Thaniyyah and the mosque of Banu Zurayq, covering about a mile.