Have You Fed the Fish?


Longhorn cowfish (Lactoria cornuta)

A translucent juvenile roundbelly cowfish, Lactoria diaphana (Photograph by Chris Newbert, Minden Pictures)

thornback cowfish in the Frankfurt aquarium



Thornback cowfish (Lactoria fornasini)


Longhorn cowfish (Lactoria cornuta)


We Have the Facts and We’re Voting Yes

Welly, well, well.

There’s a True Facts video about the mantis shrimp!

True Facts Mantis Shrimp

It’s definitely worth a view or two just to see these creatures in action.

Also, it will most definitely make you chortle. Who doesn’t need a chortle on a Monday?

Happy viewing!

Color Your Life

Well after that doozy of a post yesterday, I think I’ll stick to something more in my comfort zone.

Wouldn’t it be weird to be a mantis shrimp?

File:Curious mantis shrimp from Gilli Banta reef.JPG

The peacock mantis shrimp (Odontodactylus scyllarus) near Gilli Banta Island (near Komodo, Indonesia) – Wiki Commons

You might think that I have Photoshopped this above image using different animal parts to compose a crazy, colorful animal, but you would be wrong. It’s a real sea creature.

There are over 400 species of mantis shrimp. And these aren’t ‘shrimp’ in the conventional sense; they can reach up to a foot in length! Most are tropical, long-lived, and spend their mostly solitary lives hiding in crevices. Thus, we know very little about them, except that they’re silly looking.

And they know it too, because they have a most incredible visual system that is unparalleled in the animal kingdom. Just look at those googly eyes!

File:Mantis Shrimp.jpg

Peacock mantis shrimp by Nazir Amin (Wiki Commons)

Not only can they move their eyes independently of each other, they also are capable of using each eye for trinocular vision – seeing with three parts for each eye. To say their vision is precise would be a bit of an understatement.

The human retina has two photoreceptor types: rods and cones. Your rods are specialized for night vision (i.e. sharpness of images in black and white), while your cones are specialized for color vision. Both contribute to your visual system for you to see images. Just think of what we are able to accomplish with just two photoreceptors.

And yet, some species of mantis shrimp put us to shame because they have SIXTEEN photoreceptor types. Twelve of those are sensitive to color, including UV. The other four are dedicated to visualizing polarized light.

Mindblowing, isn’t it?

Clearly, visual communication is important for these organisms. Now, for what purpose could they possibly be using this advanced visual system?

Current hypotheses involve signaling to rivals, predators, or mates. Apparently, their bright markings can make them appear bigger and accentuate their weapons (i.e. claws), which could be helpful if they want to detract a rival or predator or attract a mate. They also actively fluoresce before mating. So perhaps they have evolved such an elaborate visual system as a means to secretly communicate with each other. None of their predators seem to have as complex vision, so they can enjoy the benefit of signaling to the object of their affection without being detected and preyed upon.

And did I mention that some of them are monogamous? Given that monogamy is rare in the animal kingdom, this is a bit surprising.

So other than the fact that they are silly looking, we do know a little bit more about them. They exhibit highly complex behaviors, and I for one am looking forward to learning more about this remarkable animal. And its googly eyes.

One With The Freaks

Behold, the female anglerfish. Though a bit unsightly, she is certainly a product of her environment. Living under the extreme conditions of total darkness and desolation has set the stage for a most bizarre sexual habit beyond your wildest imagination!

Indeed, her milkshake brings all the boys to the yard.

Photo Credit: Theodore W. Pietsch

Photo Credit: Theodore W. Pietsch

See. She is just oozing sex appeal.

As a deep-ocean fish, she lives in total darkness, which means she must use something other than vision to detect her prey and mates. You probably recognize the bioluminescent lure that dangles from her head.

Photo Credit: Theodore W. Pietsch and Christopher P. Kenaley

Photo Credit: Theodore W. Pietsch and Christopher P. Kenaley

This is but one solution to the problem of prey capture. Another solution is to sit and wait for prey to come to her. Since the enormity of this ocean zone makes encounters rare, she does not have a lot of energy to go searching for more. Instead, she sits and waits to ambush prey that are captivated by the ‘flashlight’ on her head. Great, now she’s solved the dilemma of her next meal. But what about finding and attracting mates when she’s ready to get freaky?

For a moment, let’s think about the life of a male anglerfish. His one goal in life is to find a female – a mere sprinkle that never moves in a landscape of dark nothingness. How will he accomplish this feat?

There are almost 320 species of anglerfish, and almost half of all families feature extreme sexual dimorphism – females are much bigger in size than their suitors. The largest anglerfish species is over 6 feet long. This specimen was likely a female, as are most individuals photographed. In other species, the dwarf males may be as tiny as 6.2mm in length!

Why so tiny?

Instead of wasting time growing larger, some male anglerfish opt to mature quickly so they can race to find a female as soon as possible. Once he begins the race, he presumably hones in on long-range pheromones emitted by the female.

Sniff, sniff, sniff, sniff, sniff, sniff, sniff, sniff, sniff, sniff, FEMALE!!!!!! Let the sexual parasitism begin.

Photo Credit: Theodore W. Pietsch

Photo Credit: Theodore W. Pietsch

See that wee little bump up there on the female’s back? That’s a male that has fused to her for life by biting onto her flesh. Biting her releases an enzyme that digests both his mouth and her skin, allowing full-on fusion of their bodies. Now that’s a commitment! Why would he give her up after he won the lottery by finding her? Imagine the despair of trying to find another mate in the vast, dark bathypelagic zone. Instead, he concedes to the ultimate form of monogamy.

But not from her perspective.

In some species, a female can have anywhere from two to eight males attached to her at once! Once attached, these males degenerate into little more than a pair of testes that may be used at her whim! He gets a mate, and she gets a personal sperm bank!

The reason these males are referred to as sexual parasites is because in some species, the males’ fusion with the female also entails him fusing with her circulatory system for his own life support. Though he doesn’t require much since he is small, the female must sustain the male throughout his life. Still, a small price to pay for an immediate source of sperm in desperate times.

Sadly, parasitic males may never mature and will die unless they find a female. If only Shakespeare had known of this age-old love story! I suppose this cartoonish-version of such a weird reproductive strategy will have to suffice instead. Enjoy!

Weird Fishes

Have you ever stopped to consider how awesome parasites are? While it’s not cool to be the host, per se, the absurd creatures that fall into this category are certainly worth our awe. I wanted to share with you not a bizarre mating story, though there are a fair share of parasites yielded from those. No, this is a story about a bond much greater than that formed between mates.

Our subject: the tongue-eating louse, Cymothoa exigua. This is a bit of a misnomer – more like, tongue-eroding-by-cutting-off-the-blood-supply-and-eventually-replacing-its-host’s-tongue-entirely!! But that’s a mouthful.

This terrifying crustacean enters a fish’s gills as a larva and attaches to the base of its tongue, where it starts to leech its host’s blood supply. Over time, it develops into a nasty, overgrown lice, engorging on the fish’s blood at the expense of the tongue. The tongue withers, and who else to take its place but the lice? Not only does it continue to feed off the fish’s blood supply, it also devours anything the fish attempts to eat. Check out this hijacked fish tongue!

Cymothoa exigua (Photo Credit: Dr. Nico Smit)

Cymothoa exigua (Photo Credit: Dr. Nico Smit)

Nom nom nom. How would you like to find that in your sushi?

Oddly enough, the fish survives despite the malnourishment, and they live happily ever after. True story. Why this didn’t make it into The Little Mermaid or Finding Nemo, I’ll never know.

From an evolutionary perspective, it is often a bad thing for a parasite to kill its host. If it is sustaining itself off of the life of another individual, shouldn’t it do everything in its power to make sure that individual remains alive? This isn’t true for all parasites, particularly ones with multiple hosts and complicated life cycles. Seems like this parasite’s a keeper though, so cuddle up!