Big Brother ponies were introduced to the My Little Pony line in Year 5. They were the first male ponies in the line, and the only adult male ponies. They were larger than the other ponies and had hair around their fetlock or ankle area, similar to a Clydesdale. All of the Big Brother Ponies were earth ponies.
A second set of Big Brother Ponies was released in Year 6. The ponies in both sets each came with a plastic hat that would fit above their ears and a fabric bandana that could be worn around the neck.
The Mountain Boy ponies were also released in Year 6 but were sold exclusively in the UK. The Mountain Boy Ponies were just like the Big Brother Ponies and had weather-themed names and symbols. Because they were only sold in the UK, they are now highly sought-after by collectors.
In Year 7, the Big Brother Ponies appeared as dad ponies in the Loving Family Ponies line. This line featured mom, dad, and baby ponies. The symbols on the baby ponies had a combination of designs from both the mom and dad ponies.