Possibly they were multifuncional..

It has to be said though that slow cooked meat is both extremely tasty and highly digestible..

Create a fire (With the addition of stones) possibly at night and so utilize the heat and light. cook the tender parts of meat over the fire. Then add some of the hot stones to water and stew tougher joints of meat with any herb and roots that can be found. Maybe some pulses or cereal and by morning a delicious and hearty meal will be ready..

The stones left in the fire will help keep the 'camp' warm though the night..