Ah, Christmas. The time of cozy family get-togethers, presents, embarrassing sweaters, somewhat excessive amounts of food, terrible music, and of course indoor trees. We all look forward to this time of the year, but in some places it is Christmas all year round, thanks to the christmas tree worm. The colourful feeding appendages of this little tube worm indeed resemble christmas trees remarkably well, providing a nice holiday-themed decoration to the usually already festively coloured coral reefs. Continue reading “Weekly Water Critter – The Christmas Tree Worm”
This is a suggestion for those who have always wanted to have an aquarium, but were unsure about what kind of fish to put into it. After all, some fishes can be a bit boring, behaviour-wise, so if you want your aquarium to be more than just a kind of screensaver or animated wallpaper, the archerfish is the way to go, for it has one of the most adorable hunting behaviours you’ll ever find. In its preferred natural habitat, the mangrove forests of South-East Asia, there’s a lot of vegetation floating on and hanging over the water, with many delicious bugs on them. Only, they’re just out of reach. Continue reading “Weekly Water Critter – The Archerfish”
Ask anyone for a list of five fish species and there’s likely to be a tuna among them. This fame is of course not entirely unrelated to the fact that we consume it in rather large quantities, which has led to a serious decline in tuna stocks around the world (making the old nickname “common tunnyfish” somewhat less fitting nowadays). What few people realise, however, is that the tuna is one of the top predators of the oceans, right up there with the big sharks and toothed whales. Continue reading “Weekly Water Critter – The Tunnyfish”
After some soul searching I have recently decided to expand my territory from weekly fishes to weekly water critters in general, for the seas, lakes and rivers of the world are filled with too many amazing animals to just limit myself to the scaly ones. And what better way to start than by presenting one of my favourite animals of all time, the little marine sea slug Glaucus atlanticus. Known by various wonderful names including sea swallow and blue dragon, this stunningly beautiful creature employs one of the most nifty acts of thievery in the animal kingdom. Continue reading “Weekly Water Critter – The Blue Dragon”
Fishes can be quite slippery. Slimy even. Grabbing hold of one can be rather challenging. There are exceptions of course, sharks for instance are famously unslippery (though one might be wary of grabbing a shark for reasons of personal safety). At any rate, fish-eating fishes have had to deal with the problem of slippery prey for ages, and have come up with two main solutions. The first is suction-feeding, where the predator creates negative pressure in its oral cavity to suck in and swallow its prey, thus avoiding the need to grab onto the slippery victim. The other is to use teeth. Lots and lots of teeth. Continue reading “Weekly Fish – Choking Fish Syndrome (Fish Maws Part III)”
Fishes are a bit unsubtle when it comes to teeth. In their various grabbing, biting, crushing and grinding exercises, many fishes employ teeth not just in their jaws, but also elsewhere, such as on the palate or their gill arches. Indeed, the gills can play an important role in moving food from the mouth down into the stomach. Many fishes have these so-called “pharyngeal jaws”, but it is only in the moray eels that they are truly worthy of the name.
Continue reading “Weekly Fish – The Four-Jawed Moray Eel (Fish Maws Part 2)”
Most mammals and birds have fairly straightforward mouths; two jaws with single rows of teeth (or none in most birds) and a single joint that lowers or raises the lower jaw, thus opening and closing the mouth. Fishes, however, show a truly staggering diversity in the way they use their mouths, so the coming few weekly fishes will concern fishes with distinctive ones. First up, the most gaping maw of them all. Continue reading “Weekly Fish – The Gulper Eel (Fish Maws Part 1)”