Dolphins perform analogous task to pigeons.
One object is placed in the water and then they have a choice of three objects. Dolphin obtains information about the identity of the objects using its biological sonar. Dolphins also show evidence of accumulating information over successive glimpses of the object. Wearing soft removeable eyecups, the dolphin stationed under water and directed its echolocation clicks at a submerged target located in front of it. Following the dolphin's examination of this target, the object was removed from the water and three other targets were lowered.