Grimbeorn the Old
was the son of Beorn
Like his father, he was able to take the shape of a bear.2
After the death of his father, Grimbeorn became the chieftain of the Beornings.
Grimbeorn dwelt in the Vales of Anduin and his people kept the lands between the Misty Mountains and Mirkwood free of both Orcs and Wolves1
. They kept the High Pass and the Ford of Carrock open for travelers at the time of the War of the Ring. Glóin told Frodo at the Council of Elrond that the Beornings took a high toll for their services and that they were not overly fond of Dwarves.
1 - J.R.R. Tolkien, The Fellowship of the Ring, Many Meetings
2 - J.R.R. Tolkien, The Hobbit, The Return Journey