Dromilites belli was a sponge crab, related to modern dromiid crabs famous for carrying living sponges or other objects over their backs. The rear legs of living sponge crabs are modified to hold this covering in place, providing camouflage and sometimes a chemical or physical defence from predators.

If D. belli behaved like its living relatives, it may have moved across the London Clay seabed almost disguised as part of its surroundings while feeding opportunistically on small animals and carrion. That makes sponge crabs one of the most engaging examples of behavioural camouflage in the fossil crab fauna.