Do you know why the Scripture goes into the details of this Horite family? There are probably many reasons, but one is that it shows us at least a general picture of what happens in the line of Esau. Remember, he had married Canaanite women as well as a daughter of Ishmael. Well, these are Esau's Canaanite/Horite in-laws, who lived in Seir. (As you may have already noticed, the place is named after Seir the Horite.)
Verses 22-28 go further in the genealogy of this family, and give us the names of the sons of these Horite chiefs:
"The sons of Lotan: Hori and Homam. Timna was Lotan's sister." (Genesis 36:22 NIV) Note that this woman Timna was Esau's son Eliphaz's concubine, who bore him Amalek. (Genesis 36:12) Later, the Amalekites became enemies of Israel.
"The sons of Shobal: Alvan, Manahath, Ebal, Shepho and Onam." (Genesis 36:23 NIV)
"The sons of Zibeon: Aiah and Anah. This is the Anah who discovered the hot springs in the desert while he was grazing the donkeys of his father Zibeon." (Genesis 36:24 NIV) In Genesis 36:14, Esau's wife Oholibamah is described as "the daughter of Anah and granddaughter of Zibeon." Therefore, Esau is related to the man Seir in several ways: Esau's son Eliphaz has Seir's daughter as a concubine, and Seir's son Zibeon is the father of Esau's father-in-law Anah.
This makes me think about how Esau's decision to marry Canaanite women contributed to his own son's decision to do likewise. Eliphaz was the son of Basemath (daughter of Ishmael). In fact, Esau had married Basemath when he realized that the Canaanite women were displeasing to his parents. Yet he apparently did not stop Eliphaz from marrying such a woman. I mean, each man is responsible for his decision to do so, but Esau certainly did not lead his son to marry a person who was following the God of Israel. I suppose that this is in line with Esau's general disinterest in spiritual things.
To add to the confusion, Seir's next son is also named Anah: "The children of Anah: Dishon and Oholibamah daughter of Anah." (Genesis 36:25 NIV) O.K. -- if, as Genesis 36:14 says, Oholibamah is the 'daughter of Anah and grandaughter of Zibeon' and, if Genesis 36:25 says that Anah is another son of Seir, then the only way that I can see of reconciling this is 'Anah = Anah', in other words, that the two Anah's are actually one person. Perhaps Seir adopted his own grandson and thus Anah (actual son of Zibeon) is considered Seir's 'son'. I am by no means an authority on the culture, but later in Genesis 48:5-6, Jacob counts his son Joseph's sons Ephraim and Manasseh as his own, so perhaps this is a cultural practice. It does not seem to only occur upon the death of the actual father, for Joseph was still very much alive when Jacob adopted his sons. Rather, at least in the case of Joseph, it seems to be a mark of esteem or special favor. These sons would inherit a portion of their grandfather's estate. So perhaps a similar 'adoption' is going on with Anah.
Next, in Genesis 36:26 (NIV), "The sons of Dishon: Hemdan, Eshban, Ithran, and Keran. As above, Dishon is listed both as a son of Seir (Genesis 36:21) and a son of Anah (Genesis 36:25). Again, these could be the same Dishon (another 'adoption') or two different men. It would not be inconceivable for a brother to name his son after his own brother. Since no explanation is given, we can only speculate.
"The sons of Ezer: Bilhan, Zaavan and Akan. The sons of Dishan: Uz and Aran." (Genesis 36:27-28 NIV) [Note: In the OT book of Job, Job is said to come from the land of Uz (Job 1:1)]
Finally, there is a summary statement regarding the sons of Seir who were Horite chiefs: