Thursday, October 7, 2010

How some fish are predators on land.

Not only are catifish a terror in the water, but one particular species, Channallabes apus, terrorizes insects and it's prey on land at the waters edge. They found this "eel catfish" in the muddy swamps of tropical Africa. The reason that this fish is so interesting is because of it's ability to actually come out of the water to capture its prey on land at the waters edge. One of the main reasons that the fish is even able to do this is because of the flexibility of its head and the extraordinary way that it is able to bend its head. (Kind of like a neck? I think so)

The diet of the eel catfish consists of terrestrial insects that usually live right at the waters edge. The way that the catfish is able to capture these prey is in a class all its own. The fish literally lifts it's upper body up out of the water after propelling the head up and then bends its head down towards the ground allowing it to grasp on to the prey, while opening and closing it's mouth until the prey is safely in it's jaws. Along with this, the catfish has this rostro-caudal expansion wave, which is when the mouth opens wide, followed by an extensive hyoid depression (similar to the eel previously viewed in class). This allows there to be a little bit of suction on the prey however, on land this suction is not really enough to pull prey into the mouth.

As seen above, the bending of the neck is really not seen among other fish really at all, but is seen in mudskippers. Doing this action does require a type of ventral flex along the vertebral column. This catfish is incredible and one more fascinating fact is that although early stages of tetrapods had the ability to put weight on their pectoral fins, research on this animal shows that it is actually not necessary because of the way that the fish can dorsally flex and bend it's head.

Amanda Jones

Nature 440, 881 (13 april 2006) doi:10.1038/440881a; Published online 12 April 2006

1 comment:

  1. It would be interesting to see around what time this adaptation evolved in the eel catfish. I took a quick glance at the paper bud didn't see a date. Did you come across one?