We all know plants need water to bloom, but who knew they would actually scream if they are thirsty. Scientists recently discovered that dry tomato and tobacco plants make ultrasonic plopping sounds when they are dehydrated. How exactly these sounds are produced remains to be discovered. The most likely explanation, however, is the popping of bubbles in the plants’ water-carrying tissues. This would be equivalent to humans’ creaking joints. Therefore, it might be just a feature of the plant's physiology as opposed to an intentional scream for help. It does, however, sound more dramatic to say ‘plants scream’, so I will. The human ear cannot hear these plopping sounds, hence why you never noticed a plant screaming, though, your dog might notice it. The sound emission is not unique to tomato and tobacco plants, similar screams are detected in corn, wheat and cacti. Whether they are intentional screams or not, the sounds can be of great use: by using microphones in greenhouses and on fields to pick up these ultrasound plant screams, farmers might be able to know when their plants need to be watered and when they are nicely satiated.