Elephants are endangered because of their ivory tusks. But nowadays they are least concerned, only some species of elephants are only endangered.
because some animals get eaten by other animals or get shot by hunters, making less in the world.
Deforestation, unfortunately. Giant Pandas live almost exclusively on bamboo. Without vast resources of this product, they starve.
I am sure a jaguar would take an elephant calf if it could. However, elephants are native to Africa and Asia. Jaguars are found in South America, so it would be rather unlikely that they would meet!