If you have Aphids on your plant new growth and on the underside of the leaves, it is possible that the ants are attracted to and feeding on the sugary discharge left by the aphids. Get rid of the aphids and the ants will follow. The link below gives advice on the garden pest as well as methods of getting them off your plants.
I hope this helps get rid of the ants on your elephant ear plants. Have a nice Thanksgiving
