Anas, see that nothing is given to this child until he is brought to Allah's Apostle ﷺ in the morning, so that he should chew some dates and touch his palate with it. I went to him in the morning and he was in the garden at that time having the mantle of Jauniyya over him and he was bus in cauterising (the camels) which had been brought to him (as spoils of war) in victory (over the enemy).  

لِي يَا أَنَسُ انْظُرْ هَذَا الْغُلاَمَ فَلاَ يُصِيبَنَّ شَيْئًا حَتَّى تَغْدُوَ بِهِ إِلَى النَّبِيِّ ﷺ يُحَنِّكُهُ قَالَ فَغَدَوْتُ فَإِذَا هُوَ فِي الْحَائِطِ وَعَلَيْهِ خَمِيصَةٌ جَوْنِيَّةٌ وَهُوَ يَسِمُ الظَّهْرَ الَّذِي قَدِمَ عَلَيْهِ فِي الْفَتْحِ  

So far as I know (he was cauterising) their ears.  

أَنَّ أُمَّهُ حِينَ وَلَدَتِ انْطَلَقُوا بِالصَّبِيِّ إِلَى النَّبِيِّ ﷺ يُحَنِّكُهُ قَالَ فَإِذَا النَّبِيُّ ﷺ فِي مِرْبَدٍ يَسِمُ غَنَمًا قَالَ شُعْبَةُ وَأَكْثَرُ عِلْمِي أَنَّهُ قَالَ فِي آذَانِهَا  

We went to Messenger of Allah ﷺ as he was in the fold and he was cauterising the animals of the flock and I think (he was cauterising them) on their ears. This hadith has been narrated on the authority of Shu'ba through another chain of transmitters.  

سَمِعْتُ أَنَسًا يَقُولُ دَخَلْنَا عَلَى رَسُولِ اللَّهِ ﷺ مِرْبَدًا وَهُوَ يَسِمُ غَنَمًا قَالَ أَحْسِبُهُ قَالَ فِي آذَانِهَا وَحَدَّثَنِيهِ يَحْيَى بْنُ حَبِيبٍ حَدَّثَنَا خَالِدُ بْنُ الْحَارِثِ ح وَحَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ حَدَّثَنَا مُحَمَّدٌ وَيَحْيَى وَعَبْدُ الرَّحْمَنِ كُلُّهُمْ عَنْ شُعْبَةَ بِهَذَا الإِسْنَادِ مِثْلَهُ  

I saw in the hand of Messenger of Allah ﷺ an instrument for cauterisation and he was cauterising the caracia collected as Zakat.  

رَأَيْتُ فِي يَدِ رَسُولِ اللَّهِ ﷺ الْمِيسَمَ وَهُوَ يَسِمُ إِبِلَ الصَّدَقَةِ