Instructions
Look for a Great Sabrecub. Great Sabrecubs look like bright yellow leopards with bushy red manes. When you find one, battle it and select the "Scout" command to add it to your party.
Find a Material-type monster. The Material type is a family of monsters, and you can select any monster from that family to breed the Jumping Jackal. Examples of Material monsters include Shadow, Sptinik and Dancing Flame.
Battle with your monsters until they reach at least level 10. You cannot synthesize the monsters until they are at least level 10.
Go to any scout post and use the synthesis booth there. Select "Synthesize." Select the Great Sabrecub and the Material-type monster. Tap the Jumping Jackal when it appears to get that monster.