Cold seeps and hydrothermal vents are the only known communities that do not rely on photosynthesis for food and energy production. Unlike hydrothermal vents, which are short-lived environments, cold seeps leak oil and gas slowly. Probably because of the cooler temperatures and stability, many cold seep organisms are much longer-lived than those inhabiting hydrothermal vents. These worm grow very slowly, but can reach lengths of over 10 feet (3 metres). This means individuals may live over 250 years.