Yes, some are.
big
small
5 feet .
there arms are longer
5 to 10 feet
According to livescience.com, male gorillas commonly stand over 6 feet (1.83 meters), and weigh over 400 pounds (181.5 kg). Female gorillas are somewhat shorter, and weigh about half as much. There also exist claims of gorillas approaching 7 feet (2.13 meters) and 600 pounds (272 kg), though these are unverified.
It helps them move quicker
Orangatan
29 inches
probably not, due to the fact it is found where gorillas are not found usually, plus its feet are supposedly bigger than a gorillas.
To protect themselves from their enemies.AND TO EAT.