From Tar Valon Library
Unless stated otherwise, all information herein is taken from TWoRJTWoT, Ch. 18.
To'raken are one of the Seanchan exotics, taken from worlds accessed via the Portal Stones to fight Shadowspawn. They are large flying animals, that resemble raken, except larger and brown rather than grey and herbivorous not omnivorous. They are not as agile or fast as raken, but are stronger and can fly for much greater distances without rest, or carry heavier loads. Thier primary purpose is transportation of troups or cargo, transporting as much as a thousand pounds over distances of two hundred miles. They are ranked lower than raken and a morat'raken would not normally be ordered to fly a to'raken, though they would be capable.