Tuesday 22 June 2010

Deep Sea Anglerfish

Image source
There are a couple hundred different species of anglerfish, living in open water, the deep sea or the ocean floor. What they all share is the hunting equipment that lends them their name, a fleshy growth on the head that ends in a bulb containing bioluminescent bacteria. This is used as a lure to attract unsuspecting prey like a moth to a flame, or to a really big mouth. A really, REALLY big mouth. Anglerfish have maws that occupy the entire front of the beast. Some appear to be more jaw than fish, or all jaw with a bit of fish to get the jaws to where they want to go. They also have extremely long, backward inclining teeth, to the extent that some anglerfish don't appear to be capable of actually closing their mouth.

In the abyssal darkness of the deep sea, it's so far so good for the anglerfish. She attracts her prey with the lure and she's armed to the teeth with teeth, but who knows what she may find? What if the prey is even bigger than herself? Well, those extravagent dentures can actually be depressed to provide a smooth passage into the stomach, those massive jaws can be distended to make them even BIGGER, and the stomach can expand to surround anything that can physically get in. All in all, the anglerfish can eat fish and squid twice as big as itself. Nasty.

Of course, there's one other thing. It's all very well eating and being alive and that, but what about the next generation? How does one find a mate in this unforgiving, largely empty environment? The anglerfish has an answer. The female releases pheromones that attract males to her. He turns out to be of humble appearance and a tenth of her size. He attaches himself to her body and atrophies until he's little more than a pair of gonads with her blood literally running through his veins. Very much the bread winner, the female anglerfish can now have her eggs fertilised whenever she's ready, without having to seek out her true love. Actually she can have half a dozen or more males attached to her, but that's fine, right?


By the way, the video above is taken from The Blue Planet, a major miniseries all about life beneath the waves. It's narrated by Sir David Attenborough, which is an immediate Seal of Excellence, and it really is quite wonderful. The full series is available on DVD,

US:                                     UK:

There's also a book, children's book and even the soundtrack is available! It really is a great series.

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