John Lynch beat me to this story about catfish feeding on land, so I'll be brief. It shows how the eel catfish, Channallabes apus, can manage to take an aquatic feeding structure and use it to capture terrestrial meals. Many fish rely on suction feeding: gape the mouth widely and drop the pharyngeal floor, and the resulting increase in volume of the oral cavity just sucks in whatever is in front of the animal. That doesn't work well at all in the air, of course—try putting your face a few inches in front of a hamburger, inhale abruptly, and see how close you come to sucking in your meal. So how does an aquatically adapted feeder make the transition to eating on land?
The pictures and the movie make it clear. The fish is making the same pharyngeal movements, but it's also bending its head ventrally and pinning the prey between mouth and substrate before slurping it in.
a, Average, time-scaled kinematic profiles of the gape angle (red) and hyoid depression (green) in catfish capturing land-based prey (solid lines) compared with catfish bottom-feeding in water (dashed lines). Time value of 100% corresponds to maximal hyoid depression (see supplementary information). Note that the timing and range of mouth opening and hyoid depression are similar in both environments, resulting in a rostro–caudal sequence of head expansion. b, Measurement of gape angle (red) and hyoid depression (green). c, Posture of the skull and anterior part of the vertebral column during terrestrial feeding. d, High-speed-video frame of C. apus capturing a beetle on land. The inclination of the head towards the substrate is much steeper during terrestrial than during aquatic prey capture. Scale bars, 10 mm.
You can see what it's doing much better in the movie below. I'll warn you that it's a bit alien looking, with this slimy, beady-eyed creature draping its barbel-ringed mouth over a small piece of cod, gulping a few times, and then slithering away.
The authors make the point that the same anatomical features that make it possible for the eel catfish to snack on terrestrial prey are also found in fossil tetrapods, like Ichthyostega.
Van Wassenbergh S, Herrel A, Adriaens D, Huysentruyt F, Devaere S, Aerts P (2006) A catfish that can strike its prey on land. Nature 440(7086):881.
- Log in to post comments
That's someone's arm in a sock puppet, right?
A wet sock puppet.
Love those crunchy land bugs.
Tara beat you to this one, too.
Comparing this to Tiktaalik makes a good example for how evolution underpins much of biology.
wow... way too cool. If I would've had the stomach for it, I'd have picked bio over materials science. Of course, that's a big if.
Does anyone know if catfish do this in the wild? For example, if a catfish swimming near shore saw a meal, would it flop onto land and eat it?
Interesting that Channallabes is a clariid catfish, more commonly known as walking catfishes. I wonder if this behaviour is also present among the more common Clarias catfishes, or the unrelated climbing perch Anabas.
Yes, but no. As I understand it, it's not an actual catfish, but merely a species known as the eel catfish. And whether it actually does, to quote from the paper
So I'd mark that down as a 'yes.'
I'd like to have seen film of the thing eating that bug. From the movies on the Nature site, it looks like the slurping was aided by the ability of the fish to make more or less a seal around the piece of cod. The mouth of the fish also doesn't seem much like those of any of the early tetrapods, or do their reconstructions fail to show a cheek?
"it's not an actual catfish, but merely a species known as the eel catfish"
Huh? It is a member of Order Siluriformes, thus an "actual catfish." And I'd suggest that the modifier "merely" is totally unwarranted in discussing anything about this extra-cool animal.
I've got to say, that most teenagers are quite capable of inhaling a hamburger..
-jcr
Mind yourselves walking by the riverbank, so.
Re: "actual" catfish--
"Catfish" seems to be kind of an umbrella term. Cf.:
Herman JR. Candiru: urinophilic catfish. Its gift to urology. Urology. 1973 Mar;1(3):265-7.
Despite coming dangerously close to an appeal to authority on this, I feel that I'm on solid ground when I state that, having grown up in Alabama, I know catfish. And something that swims up your urine stream into your urethra, where it lodges with its spines and has to be surgically removed, is no catfish.
So I always take the term "catfish" with a big grain of salt (unless it refers to Ictalurus punctatus, in which case I take it with cornflour batter and hushpuppies. :)
try putting your face a few inches in front of a hamburger, inhale abruptly, and see how close you come to sucking in your meal.
Works pretty well for my dog.