Craftfin

The craftfin split from its ancestor and changed dramatically. It has become a social creature that lives in colonies. They have grown smaller in size and their fins have grown larger as well as their mandibles which they use to manipulate objects and construct the burrows they live in. Their sense of touch has greatly improved as well and it has become their main sense used to find their way in their environment. Their head fins have built great muscles which allow them to flip and move through shallow waters and even mud. Their blue blood gills have also changed so they can breathe when staying inside the mud by absorbing the oxygen from the water inside the soil.

They have changed their social structure completely. They no longer live alone and now live in colonies of 20-50 members at average. These colonies are huge burrows built usually on the river bed or the deeper parts of the marsh but sometimes on the banks as well. These burrows are made of a special mixture of mud and their feces chewed together. These burrows are not very strong and will usually break after a decade or two, long after the colony falls apart itself. There are 4 castes in the craftfin colony: workers, soldiers, scavengers, and the hormone-queen. The workers are smaller craftfins with two sets of big mandibles. They are in charge of building the burrows, maintaining them, and feeding the hormone queen as well as mating for her. The soldiers are much bigger and have a long sting which they use to paralyze their hunt. They are the carnivore hunters of the colony who go out in small packs and kill small preys which they chew and keep in their stomachs. When they return to the burrow they throw it up and share it with the rest of the colony. The scavengers act the same but search only for dead victims.

The hormone-queen is a unique individual. There is only one hormone-queen in every colony and it is the only one that can give birth. It is in fact both hormone sex and female as it has a birth canal though it has no female chromosomes. It is impregnated by two workers who reproduce and lay their eggs inside the queen’s reproduction organ. They are then absorbed inside her and stays there for 2 weeks. Finally it will lay fertile eggs which will be carried by the workers to chambers inside the burrow until they will hatch. The young won’t be treated in any way and will join the colony as a productive member as they hatch. The caste of the hatching craftfin will be chosen 4 weeks after they hatch by hormones released from the queen according to the needs of the colony. In very cold winters when the lakes freezes over and food is rare the whole colony can hibernate by burring themselves inside the burrow and staying hibernated until the ice will melt.