The jackal, Tabaqui, is a character who causes a great deal of mischief in The Jungle Book. The wolves, Baloo, and Bagheera hate Tabaqui, and their reasons are given when he first appears in the story "Mowgli's Brothers":
It was the jackal—Tabaqui, the Dish-licker—and the wolves of India despise Tabaqui because he runs about making mischief, and telling tales, and eating rags and pieces of leather from the village rubbish-heaps. But they are afraid of him too, because Tabaqui, more than anyone else in the jungle, is apt to go mad, and then he forgets that he was ever afraid of anyone, and runs through the forest biting everything in his way. We call it hydrophobia, but they call it dewanee—the madness—and run.
The jackal tells lies and delights in mischief. In The Jungle Book he associates with the tiger, Shere Khan. He delivers messages from Shere Khan and shares in his kills. At the beginning of "Mowgli's Brothers," Shere Khan attacks a wood-cutter's camp, but he loses track of the baby, Mowgli. Tabaqui leads him to the wolves' den, where Mowgli is hidden. This leads to a confrontation between Shere Khan and the wolf pack, which causes a life-long vendetta between Mowgli and Shere Khan.
He is also considered mad, and jackals more than any other creature tend to contract "hydrophobia"—what is now commonly called rabies. Thus when Mowgli is among the monkeys, who are wild and nonsensical, he thinks to himself "Tabaqui the Jackal must have bitten all of these people!"
The jackal eats food that the other animals consider below them. He scavenges from human trash heaps, and as he himself says, "for so mean a person such as myself, a dry bone is a good feast."