It's also probably why they become nocturnal as they can rest during the day without going to the surface for a longer period of time. Then become active during the night. However most of the lower jaw species of bichirs are found in much open area where there are only few to none vegetation at all. With only rocks and probably some driftwood to hide. This is probably why they grow so much bigger in size and also probably a self defense against other predator as they are an open target. The larger size makes up for not being eaten. Compare to the upper jaw species that are mostly found in area where there are more vegetation to give them cover. They grow much smaller or medium size. Except for the ornate, weeksii and teugelsi which grows bigger. The smaller size is another adaptation to enable them to hide is a smaller area such as roots of floating plants or other vegetation in the area. By being bigger in size in this type of area, they will become target to land base predators or aquatic birds that preys on aquatic animals as they can hardly hid themselves. Again with the exception to the ornate, weeksii and teugelsi. Probably these 3 larger upper jaw species stay in much deeper area where they can stay under the water for longer period of time. Then hunts during the night as most predatory aquatic birds are sleeping during the night.
