No mektoub on Silan, only on Main Land (Atys continents).

Free players may purchase one mektoub Mount. Subscribed players may purchase three packers and a mount, for a total of four mektoubs. At advanced levels, packers are very useful to the forager and crafter. Mektoubs must be fed, so if you are traveling a long ways, be sure to buy food from the stable boy and move the food onto each animal. Otherwise, take the mektoub to the nearest stable and give the Enter Stable command from the animal window. A feeding plan can be purchased from the stable boy (cheaper than forage bales). An animal kept in the stable will last indefinitely. Mounts can go to other lands with you. They must go into the gate after you, (by issuing the “follow me” command). Beware though; they can be killed. A mount can be killed by MOBs – even as low level as growling gingos – if you are sitting on it. If a mektoub dies, you will see a skull icon on the screen advising you of the time remaining to unload the carried items before the mektoub disappears. You can neither magically heal nor resurrect a mektoub.

More on Mektoub FAQ.