Unlike all other vertebrates, coelacanths possess an intracranial joint and an associated basicranial muscle. The purpose of this structure is disputed, with some experts arguing that it assists with suction feeding, while others suggest that it increases bite force. Another dissimilarity is their notochord, which in coelacanths is a hollow tube filled with fluid. Coelacanths have a fatty organ that serves the same purpose as a swim bladder. It was recently discovered that, within this fatty organ, a vestigial lung can be found that is surrounded by small hard plates. It is believed that these plates were involved in lung volume regulation in an ancestral species, but have become rudimentary in extant coelacanths.
Females are larger in size, and have higher thickness ratios and metabolic rates than males. Average mass of adult females is 82.1 kg, and average length …show more content…
During daylight hours, coelacanths gather in caves roughly 100 to 200 m below the water surface. Coelacanths were found between 150–253 m depth, their preferential depth seems to be around 200 m; the water temperature ranged between 16.5–22.8° C. During the day coelacanths aggregate in small non-aggressive groups in sheltered lava-caves. Caves might be a limiting factor for distribution. At night they leave the caves for hunting by drifting singly along the steep lava slopes. They migrate between different caves located within a large home range covering more than 8 km coastline. Coelacanths are site-attached, some for a period of at least 2