Vānara Jātaka (No.342)
The Bodhisatta was a young monkey living on a river bank. A female crocodile in the river longed to eat his heart and her husband persuaded the monkey to go for a ride on his back in search of wild fruits. In midstream he began to sink and revealed his purpose, and the monkey, nothing daunted, said that monkeys did not keep their hearts in their bodies for fear of their being torn to pieces on the trees, but that they hung them on trees, and, pointing to a ripe fig tree, showed the crocodile what he said was his heart. The crocodile took him to the tree, and the monkey jumped ashore and laughed at him.
The story was told in reference to Devadatta’s attempt to kill the Buddha. J.iii.133 f; cf. Susumāra Jātaka (No.208).