The historians of last century could not explain the origin of these people including Al-Qara, but described the similarity they had with Somali and Ethiopian people, the Al-Qara which is the largest of these tribes and the Khatiri have the longest lineages, but the Al-Mahra(Arab Salah) the Arab say has only been noticed as a tribe for the past 700 years, being a tribe for the last 700 years means Arab Salah himself was more than 700 years ago as his descendants were a noticeable tribe at that time. Darood is roughly a 1000 years old and was noticed as tribe roughly 300 years later which is the same time Arab Salah was noticed as a tribe. Another interesting fact, Arabs(this term is becoming misleading) consider Al-Mahri(Arab Salah) as native to the land and they consider themselves immigrants, this is especially true in Oman where there is a large population of slave descendants who speak only arabic(the Rer Hamar of Oman).


also Al-Mahri settle in Socotra and speak both Arabic and a dying language known as Meheri. Al-Mahri tribe in Arabia is several hundred thousands numbers and they live in Saudi Arabia, Yemen(hadramout), Oman(dhofar) and also Qatar, Dubai. They are held at high esteem amongst arabs and respected very highly, but most of the power of Oman and Yemen goes to the Arab and the slave descendants who have been instilled by European imperialist, similar to what happened in Somalia, but these people are not disturbed infact their lands are ruled by their own Shiekhs and not government.
apart from language differences(arabic and meheri) they have a strong distinct culture in the region, a culture similar to Somali, for example their women are not subject to arranged marriage, they herd camels and ari, arabs do not herd camels they use them for transport only, they also eat digir during rainy season, they practice fircooni circumcision, their tribal structure is identical to Somali Darood tribal structure and slightly different from arabs etc. You may ask how they have kept their culture, well the area they live in is surrounded by mountains and deserts and ocean, they travel through sea only.
their connection to their Darood brethren is one that is alive, they recognize Al-Jabarti, infact you may have confused a proud Al-mahri with an arab, the Al-mahri who live in Somalia are known as Arab Salah, Daroods have also welcomed them to Somalia in Nugaal, Mudug etc.
here is a promotional video of Dhofar the strong hold of Al-mahri and traditional land.