Are the monkeys and pigs that exist nowadays humans who have been transformed?
Question

Could you please tell me about monkeys. Are they humans who were turned into monkeys for disobeying Allahs commandments? if so which people were they and what did they do?
Praise be to Allah.Maskh (transformation) refers to the changing of a person’s exterior appearance. Allah has told us in more than one place in the Quran that He transformed some of the Children of Israel into monkeys as a punishment for their disobedience towards Allah. Allah says, addressing the Children of Israel (interpretation of the meaning): 
“And indeed you knew those amongst you who transgressed in the matter of the Sabbath (i.e. Saturday). We said to them: ‘Be you monkeys, despised and rejected.’
So We made this punishment an example to their own and to succeeding generations and a lesson to those who are Al-Muttaqoon (the pious)”
[al-Baqarah 2:65-66] 
And Allah tells us their story in more detail in Soorat al-A’raaf, where He says (interpretation of the meaning): 
“And ask them (O Muhammad) about the town that was by the sea; when they transgressed in the matter of the Sabbath (i.e. Saturday): when their fish came to them openly on the Sabbath day, and did not come to them on the day they had no Sabbath. Thus We made a trial of them, for they used to rebel against Allah’s Command (disobey Allah)
 And when a community among them said: ‘Why do you preach to a people whom Allah is about to destroy or to punish with a severe torment?’ (The preachers) said: ‘In order to be free from guilt before your Lord (Allah), and perhaps they may fear Allah.’
So when they forgot the reminders that had been given to them, We rescued those who forbade evil, but with a severe torment We seized those who did wrong because they used to rebel against Allah’s Command (disobey Allah).
So when they exceeded the limits of what they were prohibited, We said to them: ‘Be you monkeys, despised and rejected’”
[al-A’raaf 7:163-166] 
And Allah says (interpretation of the meaning): 
“Say: ‘O people of the Scripture (Jews and Christians)! Do you criticize us for no other reason than that we believe in Allah, and in (the Revelation) which has been sent down to us and in that which has been sent down before (us), and that most of you are Faasiqoon [rebellious and disobedient (to Allah)]?’
 
Say (O Muhammad to the people of the Scripture): ‘Shall I inform you of something worse than that, regarding the recompense from Allah: those (Jews) who incurred the Curse of Allah and His Wrath, and those of whom (some) He transformed into monkeys and swines, and those who worshipped Taaghoot (false deities); such are worse in rank (on the Day of Resurrection in the Hell-fire), and far more astray from the Right Path (in the life of this world)’”
[al-Maa’idah 5:59-60] 
This transformation was a punishment from Allah to them for their doing that which Allah had forbidden to them. This punishment was not exclusively for the Children of Israel, rather the Prophet (peace and blessings of Allah be upon him) told us that the Hour will not begin until such transformation happens among this ummah too. He issued this warning to those who disbelieve in the divine decree (al-qadr), and those who drink alcohol and listen to singing – we seek refuge with Allah from that. 
Ibn Maajah (4059) narrated from ‘Abd-Allah ibn Mas’ood that the Prophet (peace and blessings of Allah be upon him) said: “Shortly before the Hour begins, people will be transformed into monkeys and pigs, swallowed up in the earth, and pelted with stones.” (Saheeh Ibn Maajah, 3280). 
Being swallowed up in the earth means that the earth will split open and swallow up a person, house or city, just as Allah caused the earth to swallow Qaaroon and his household. Allah says (interpretation of the meaning); 
“So We caused the earth to swallow him”
[al-Qasas 28:81] 
Pelting with stones is the same as Allah did to the people of Loot. Allah says (interpretation of the meaning): 
“and rained down on them stones of baked clay”
[al-Hijr 15:74] 
Al-Tirmidhi (2152) narrated that Ibn ‘Umar said: “I heard the Messenger of Allah (peace and blessings of Allah be upon him) say, ‘Among this ummah those who disbelieve in the divine decree (al-qadr) will be swallowed up by the earth, transformed into monkeys and pigs or pelted with stones.” (Saheeh al-Tirmidhi, 1748). 
And al-Tirmidhi (2212) narrated from ‘Imraan ibn Husayn that the Messenger of Allah (peace and blessings of Allah be upon him) said: “Among this ummah, people will be transformed into monkeys and pigs, swallowed up in the earth, and pelted with stones.” A man among the Muslims said, “O Messenger of Allah, when will that be?” He said, “When singing-girls and musical instruments become widespread and wine is drunk.” (Saheeh al-Tirmidhi, 1802). 
These ahaadeeth indicate that such transformations will happen in this ummah as a punishment for some sins. So let the Muslim beware of doing anything that Allah has forbidden. Woe be to the one who provokes the anger, wrath and vengeance of Allah. May Allah keep us all safe from the things that incur His punishment. 
But these monkeys and pigs that exist nowadays are not the people from the earlier nations who were transformed, because Allah does not enable those who have been transformed to have offspring, rather He causes them to die after being transformed, so they have no offspring. 
Muslim (2663) narrated that ‘Abd-Allah ibn Mas’ood said: “A man said, ‘O Messenger of Allah, are the monkeys and pigs those who have been transformed?’ The Prophet (peace and blessings of Allah be upon him) said: ‘Allah does not enable those who have been transformed to have offspring or children. The monkeys and pigs existed before that.’” al-Nawawi (may Allah have mercy on him) said: “The Prophet’s words ‘The monkeys and pigs existed before that’ means that they existed before the Children of Israel were transformed, which indicates that they are not from among those who were transformed.” 
And Allah knows best. May Allah bless our Prophet Muhammad and grant him peace.