The Disbeliever is just like an Animal
Allah then made a parable of the disbelievers, just as He said in another Ayah:
[لِلَّذِينَ لاَ يُؤْمِنُونَ بِالاٌّخِرَةِ مَثَلُ السَّوْءِ]
(For those who believe not in the Hereafter is an evil description.) (16:60)
Similarly, Allah said here (2:171 above)
[وَمَثَلُ الَّذِينَ كَفَرُواْ]
(And the example of those who disbelieve...) meaning, in their injustice, misguidance and ignorance, they are just like wandering animals, not understanding what they are told; if the shepherd heralds them or calls them to what benefits them, they would not understand what is actually being said to them, for they only hear unintelligible sounds. This is what is reported from Ibn `Abbas, Abu Al-`Aliyah, Mujahid, `Ikrimah, `Ata', Al-Hasan, Qatadah, `Ata' Al-Khurasani and Ar-Rabi` bin Anas.
[صُمٌّ بُكْمٌ عُمْىٌ]
(They are deaf, dumb, and blind.) means, they are deaf, as they do not hear the truth; mute, as they do not utter it; and blind, as they do not see or recognize its path and way.
[فَهُمْ لاَ يَعْقِلُونَ]
(So they do not understand.) means, they do not comprehend or understand anything.
[يـأَيُّهَا الَّذِينَ ءَامَنُواْ كُلُواْ مِن طَيِّبَاتِ مَا رَزَقْنَـكُمْ وَاشْكُرُواْ للَّهِ إِن كُنتُمْ إِيَّاهُ تَعْبُدُونَ - إِنَّمَا حَرَّمَ عَلَيْكُمُ الْمَيْتَةَ وَالدَّمَ وَلَحْمَ الْخِنزِيرِ وَمَآ أُهِلَّ بِهِ لِغَيْرِ اللَّهِ فَمَنِ اضْطُرَّ غَيْرَ بَاغٍ وَلاَ عَادٍ فَلاَ إِثْمَ عَلَيْهِ إِنَّ اللَّهَ غَفُورٌ رَّحِيمٌ ]
(172. O you who believe (in the Oneness of Allah ـ Islamic Monotheism)! Eat of the lawful things that We have provided you with, and be grateful to Allah, if it is indeed He Whom you worship). (173. He has forbidden you only the Maitah (dead animals), and blood, and the flesh of swine, and that which is slaughtered as a sacrifice for other than Allah. But if one is forced by necessity without willful disobedience nor transgressing due limits, then there is no sin on him. Truly, Allah is Oft-Forgiving, Most Merciful.)