Once you have eliminated the possibility that your bengal could be in pain, it is likely that he is calling for attention, to relieve boredom. To test this, try getting up and throwing a toy for him, or stroking him the next time he howls at night. If he is immediately on for a game/cuddle and stops howling, it may be that he is bored. You have several options to save your sleep. I presume he is an indoor cat, like our own bengal. Indoors is a very sterile environment and Bengals are highly intelligent and need several chase/fetch games each day, especially if you are out at work all day as we are ourselves. We have three cats who spend a lot of time playing with each other, and another kitten (or even a puppy) is a possible solution (it doesn't have to be a bengal). If this is not an option, you must tire him out thoroughly by the time you go to bed. Chasing round the house string games, fetching toy games and playing with water, anything interactive would be good. Three ten minute games in an evening should be sufficient to make him feel stimulated and wanted (Asian Leopard Cats are nocturnal hunters and bengals do love to play in the evening.) Cats exercise in short bursts of activity, so little and often makes for a happy bengal. We also try to bring a special present home some evenings, such as a cardboard box full of autumn leaves or a pine cone. Bengals do love stuff from "OUTSIDE!"

Hopefully some extra stimulation and attention in the evenings should make him settle down more during the night.

Our own bengal also howls, but more specifically; he will howl in the bath, asking for the water to be turned on and he will also howl at the door, asking to be let out (he is not allowed out unsupervised). We either give him what he wants or distract him with some fun.

Anne Randall adds

If you have eliminated any physical problems with your bengal and I do not think there is any reason to believe he is in any way unwell, I would say that he is lonely and wants attention. Most cats as sociable creatures and bengals particularly so.

If you would rather not let him into your bedroom at night the best thing would be to get him a companion - someone to play with and cuddle up to. I am sure he is just feeling lonely.

Henry Ritson adds