Studies have not been done on elephants; however, in horses, dogs and donkeys, the weight carrying capacity is about 20-25% of their body weight, which equates to over 600 kg for Asian Captive Elephant Working Group an average sized elephant weighing about 3,000 kg. Furthermore, the front and rear long bones of elephants are particularly strong because they do not have a bone marrow cavity, but instead have a dense bone structure. This means they can bear more weight than many other mammals. Elephant saddles should be properly cushioned and not apply pressure to the spine. If the working hours are limited and the terrain is suitable, two people in a saddle (less than 10% of the elephant's body weight) will not be an undue stressor for an elephant. The weight of one or two people without a saddle (less than 4% of body weight) would hardly be noticed.