Sponges do not have nervous, digestive or circulatory systems. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes, and the shapes of their bodies are adapted to maximize the efficiency of the water flow. Sponges can control the water flow by various combinations […]
black sun the spectacular play of starling aerobatics take place in southern Denmark two times every year when the starlings migrate to and from their breeding and winter quarters respectively. having fouraged during the day in groups of 10-15 birds they meet up at dusk to form flocks of up to 500,000 individuals before settling […]