The Yawning Hunter

Although I’m now back in Europe, my thoughts still wander to the incredible variety of marine life found in Dahab. Flicking through photos of the trip, one charismatic little creature is crying out to have its story told... Hidden within a small patch of coral on a sandy slope, we spotted a little red blob less than 10 cm long, which on closer inspection turned out to be a beautiful painted frogfish (Antennarius pictus)!

Frogfishes are certainly amongst some of the strangest things to be found under the waves, perfectly mimicking the colours, shapes and textures of sponges and corals in order to remain invisible to unsuspecting prey! They belong to the family Antennariidae, with over 48 species managing to thrive in a wide variety of marine environments worldwide, ideally where the water temperature exceeds 20ºC.

 

My favourite characteristic of these guys has to be their seemingly constant state of laziness, as their lives largely consist of sitting motionless on the reef all day, watching the world go by! Lazy isn’t really an accurate description however, as they actually lead an extremely clever lifestyle, which relies upon staying still to conserve energy and deviously force their food into providing a free home-delivery service. Perhaps there are indeed some individuals out there who are particularly lethargic even by frogfish standards, but who knows!

Unlike the majority of fishes they don’t swim very efficiently at all, and are mainly benthic dwellers (living on the bottom), relying on their leg-like fins to “walk” short distances or occasionally using jet propulsion to search for a new hunting spot. This is done by sucking water in through the mouth and expelling it through gill openings which are unusually located behind the lower pectoral fins (see photo below).

 

There is one incredible species however with a more adventurous lifestyle, the sargassum frogfish (Histrio histrio), which has adapted to blend in perfectly within bunches of floating sargassum seaweeds which drift at the surface in ocean currents. These micro-habitats are basically the motorway service stations of the open oceans, providing food and shelter for passers-by, as well as a home for certain small animals!

So ok, you are perfectly camouflaged and nobody knows that you’re there, now how do you go about finding a decent meal? Well frogfish have this covered too, having evolved a specialised lure to draw prey right in front of their mouths. A very thin see-through rod or “illicium” protrudes from the forehead, with an enticing morsel called an “esca” attached to the end. Target prey consists mainly of small fishes and crustaceans, and the esca (which is actually just a small piece of flesh) vary in shape, size and colouration to mimic small animals such as worms, shrimp and fishes. It is thought that a frogfish with a particular shaped esca might attract a particular type of prey, but studies of stomach contents show that this isn’t actually the case. Instead they tend not to be picky, and seem to grab anything that swims within reach!

The illicium is flicked tantalising above their head, hoping to stimulate a response from the nervous system of nearby targets, and entice them to venture closer within the strike zone (less than one body length away)! When ready, the frogfish rapidly extends its upper and lower jaw, creating an immense suction effect from which the prey is helpless to escape. All of this happens in only 6 milliseconds, awarding the frogfish the record for the fastest "gape-and-suck" feeding mechanism of any fish! This type of camouflaged hunting whilst luring prey into range is called aggressive mimicry. Check out this fantastic video by Fred Moberg HERE to see this action in slow motion.

If you fancy learning more about these amazingly diverse and peculiar fish, then visit this brillaint website created by passionate frogfish enthusiast Teresa Zubi! htttp://www.frogfish.ch/frogfish.html 


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