4 Real-Life Monsters

A repost of an original article published October 26, 2015.

During the Halloween season, we find ourselves surrounded by monsters in movies, stores and decorations. We laugh at the ridiculousness of it all, oblivious to the fact that there are true monsters on our planet today! Mind you, these are not monsters in that they are evil, but they do have many of the same abilities and inclinations of our own mythical werewolves, vampires, zombies and shape-shifters.

Werewolf birds:

A Barau's petrel. Photo by SEOR
available at Wikimedia Commons.

Barau’s petrel is a migrating sea bird that is most active during nights with a full moon. Researchers tied bio-loggers on the birds’ feet to track their activity levels and found that under the full moon, the birds spent nearly 80% of these moonlit nights in flight! It is thought that since these birds migrate longitudinally (parallel with the equator), they can’t use changes in day length as a cue to synchronize their breeding, so they use the phases of the moon instead.

Vampire bats:

Three different bat species feed solely on blood: the common vampire bat, the hairy-legged vampire bat and the white-winged vampire bat. Feeding on blood is not uncommon – The actual term for it is hematophagy, and it is common in insects (think of those pesky mosquitos) and leeches. Although we don’t commonly think of it this way, blood is a body tissue and, like meat, it is rich in protein and calories. The reason it has not become a more popular food source among mammals is probably because it is so watered down (literally) compared to meat, that it can’t provide enough nutrition to sustain a large warm-bodied mammal. This is where our little vampire bat friends come in… small, stealthy, and with specialized saliva that prevents their victims’ blood from clotting, these guys are able to take advantage of this abundant resource, drinking up to half of their body weight in blood every night.

Zombees:

Scientists have recently discovered some strange honey bees: They mindlessly leave their hives in the middle of the night and fly in circles, often towards lights. It turns out that these honey bees are being parasitized by a species of phorid fly called the zombie fly. Female phorid flies lay their eggs inside the abdomens of honey bees, where the eggs hatch into larvae. The larvae feed on the insides of their bee hosts until they are mature enough to leave through the poor bee’s neck (the honey bee is generally dead by this time). Once out, the zombie flies develop into adults so they can breed and start the cycle anew with a new bee host. This phenomenon is still in the early stages of discovery, so if you would like to get involved in this project by watching honey bees in your area, check out ZomBee Watch, a citizen science project to track this zombie infestation.

Shape shifters:

The mimic octopus is a small harmless octopus that lives on the exposed shallow sandy bottoms of river mouths. To avoid its many predators it has developed an amazing strategy: it pretends to be something else, morphing its body into new shapes, like the shape of a deadly lion-fish, a poisonous flatfish, a venomous banded sea-snake, or any number of other animals that live in the area. Not only does the mimic octopus change its shape, it also changes its behavior to match its “costume” to convincingly fool predators. Most cephalopods, which include octopuses, are well-known for their ability to change the color, pattern and texture of their skin to blend in with rocks, coral and plants. Furthermore, octopuses do not have rigid skeletal elements, which allows their bodies great flexibility in the forms they imitate. But this ability to change both physical appearance and behavior to switch back and forth among imitations of multiple species is unique to this astounding shape shifter.

Nature's Halloween Costumes

A repost of an original article from October 23, 2013.

Image by Steve at Wikimedia Commons.

It seems like everyone is racking their brains to come up with a great Halloween costume. But we’re not the only ones to disguise ourselves as something we’re not. Many animals put on costumes just like we do. Take this gharial crocodile for example (do you see him?), covering himself in parts of his environment to hide.

Other animals, like this tawny frogmouth below, develop physical appearances that help them blend in with their surroundings. When threatened, these birds shut their eyes, erect their feathers and point their beak in such a way to match the color and texture of the tree bark.


Image by C Coverdale at Wikimedia Commons.

Rather than hide, some animals have a physical appearance to disguise themselves as other species that are often fierce, toxic or venomous. This type of mimicry is called Batesian mimicry, named after Henry Walter Bates, the English naturalist who studied butterflies in the Amazon and gave the first scientific description of animal mimicry. This plate from Bates’ 1862 paper, Contributions to an Insect Fauna of the Amazon Valley: Heliconiidae, illustrates Batesian mimicry between various toxic butterfly species (in the second and bottom rows) and their harmless mimics (in the top and third rows).


This plate from Bates’ 1862 paper, Contributions to an Insect Fauna of
the Amazon Valley: Heliconiidae is available on Wikipedia Commons.

The bluestriped fangblenny takes its costume another step further, by changing its shape, colors, and behavior to match the company. This fish changes its colors to match other innocuous fish species that are around so it can sneak up and bite unsuspecting larger fish that would otherwise bite them back! Learn more about them here.

The fish on the far left is a juvenile cleaner wrasse in the act of cleaning another fish. The two fish in
the middle and on the right are both bluestriped fangblennies, one in its cleaner wrasse-mimicking
coloration (middle) and the other not (right). Figure from the Cheney, 2013 article in Behavioral Ecology.

But the Master of Disguise title has got to go to the mimic octopus. This animal can change its color, shape and behavior to look and behave like a wide range of creatures, including an innocuous flounder, a poisonous lionfish, or even a dangerous sea snake! Check it out in action:

The Weirdest Animals on Earth: 12 Amazing Facts About Seahorses

A seahorse in all its glory. Photo by Gustavo Gerdel at Wikimedia Commons.

1. Seahorses are fish. They include about 54 different species of fish and are closely related to sea dragons and pipefish. But seahorses are not your typical fish! A baby seahorse is called a fry (like in other fish), but a group of seahorses is called a herd (like in horses).

2. Seahorses have skeletons unlike any other fish. Unlike other bony fish, seahorses have a neck, an exoskeleton, and a prehensile tail. Seahorses do not have pelvic fins, ribs or scales. Instead, their skin is stretched over a series of bony plates arranged in rings.

3. Seahorses are terrible swimmers and can die of exhaustion if the sea is rough or the current is too strong. The only fin they have to get around with it the tiny one in the middle of their back (the dorsal fin). They use even smaller pectoral fins on the sides of their head to steer. Seahorses and razorfish are the only fish to swim upright, because it is horribly inefficient. It is a good thing they have a prehensile tail to hang on to whatever is nearby.

A pygmy seahorse in camouflage.
Photo by prilfish at Wikimedia.

4. Seahorses are experts at camouflage and can change color. They are even able to grow fleshy appendages (called cirri) that help them with camouflage by giving them a weed-like appearance.

5. Seahorses have terrible smell but amazing vision. They have the fewest genes for olfactory receptors (used in other animals for smell and taste) of any ray-finned fish species known. But seahorses have excellent vision and their eyes can work independently, meaning they can look forward and backward at the same time!

6. Seahorses eat weird. They have a toothless, tubular snout, which they use to suck up small fish and crustaceans. They swallow them whole. Seahorses do not have stomachs and don't digest very well, so they have to eat constantly.

7. Seahorses are one of the ocean's deadliest predators, with a 90% kill rate. Because of the shape of their head and their slow, finless method of movement, seahorses move with near hydrodynamic silence, barely moving the water as their stealthily sneak up on their prey. Once they are within striking distance, they snap their heads and suck up their prey. 

8. Seahorses click when they're courting and growl when their stressed. 

9. Seahorses are monogamous and pair for life. Their courtship begins with a daily dance between the couple that they do for days. The final courtship dance can last eight hours before the female "impregnates" her partner.

10. Male seahorses get "pregnant". They are the only males that take on the full responsibility of pregnancy, carrying up to 2,000 babies at a time! Although they don’t have a mammalian womb and placenta, they do have an enclosed abdominal pouch specifically for the purpose of incubating the babies. The female deposits her eggs in his brood pouch, in which he fertilizes them and incubates them for 10-45 days (depending on the species). During this time, his body undergoes a number of hormonal and physiological changes. When the babies are ready to emerge as fully developed little seahorses, seahorse dads even experience contractions as they give birth! 

11. Seahorses are evolving faster than any other group of bony fishes. Scientists have sequenced the entire genome of a tiger tail seahorse, a threatened tropical seahorse species.

12. Seahorses are under threat because of the traditional Chinese medicine trade, the pet trade, and the curio trade, all of which capture seahorses from the wild, and because of habitat depletion and pollution.

4 Real-Life Monsters

During the Halloween season, we find ourselves surrounded by monsters in movies, stores and decorations. We laugh at the ridiculousness of it all, oblivious to the fact that there are true monsters on our planet today! Mind you, these are not monsters in that they are evil, but they do have many of the same abilities and inclinations of our own mythical werewolves, vampires, zombies and shape-shifters.

Werewolf birds:

A Barau's petrel. Photo by SEOR
available at Wikimedia Commons.

Barau’s petrel is a migrating sea bird that is most active during nights with a full moon. Researchers tied bio-loggers on the birds’ feet to track their activity levels and found that under the full moon, the birds spent nearly 80% of these moonlit nights in flight! It is thought that since these birds migrate longitudinally (parallel with the equator), they can’t use changes in day length as a cue to synchronize their breeding, so they use the phases of the moon instead.

Vampire bats:

Three different bat species feed solely on blood: the common vampire bat, the hairy-legged vampire bat and the white-winged vampire bat. Feeding on blood is not uncommon – The actual term for it is hematophagy, and it is common in insects (think of those pesky mosquitos) and leeches. Although we don’t commonly think of it this way, blood is a body tissue and, like meat, it is rich in protein and calories. The reason it has not become a more popular food source among mammals is probably because it is so watered down (literally) compared to meat, that it can’t provide enough nutrition to sustain a large warm-bodied mammal. This is where our little vampire bat friends come in… small, stealthy, and with specialized saliva that prevents their victims’ blood from clotting, these guys are able to take advantage of this abundant resource, drinking up to half of their body weight in blood every night.

Zombees:

Scientists have recently discovered some strange honey bees: They mindlessly leave their hives in the middle of the night and fly in circles, often towards lights. It turns out that these honey bees are being parasitized by a species of phorid fly called the zombie fly. Female phorid flies lay their eggs inside the abdomens of honey bees, where the eggs hatch into larvae. The larvae feed on the insides of their bee hosts until they are mature enough to leave through the poor bee’s neck (the honey bee is generally dead by this time). Once out, the zombie flies develop into adults so they can breed and start the cycle anew with a new bee host. This phenomenon is still in the early stages of discovery, so if you would like to get involved in this project by watching honey bees in your area, check out ZomBee Watch, a citizen science project to track this zombie infestation.

Shape shifters:

The mimic octopus is a small harmless octopus that lives on the exposed shallow sandy bottoms of river mouths. To avoid its many predators it has developed an amazing strategy: it pretends to be something else, morphing its body into new shapes, like the shape of a deadly lion-fish, a poisonous flatfish, a venomous banded sea-snake, or any number of other animals that live in the area. Not only does the mimic octopus change its shape, it also changes its behavior to match its “costume” to convincingly fool predators. Most cephalopods, which include octopuses, are well-known for their ability to change the color, pattern and texture of their skin to blend in with rocks, coral and plants. Furthermore, octopuses do not have rigid skeletal elements, which allows their bodies great flexibility in the forms they imitate. But this ability to change both physical appearance and behavior to switch back and forth among imitations of multiple species is unique to this astounding shape shifter.

The Weirdest Animals on Earth: 12 Amazing Facts About Octopuses



Photo of a day octopus by
Ahmed Abdul Rahman available
at Wikimedia Commons.

1. The plural of octopus is octopuses. How an English word is pluralized depends, in part, on its origins. Latin words that end in –us are generally pluralized by replacing the –us with an –i (the plural of alumnus, for example, is alumni). But octopus is not Latin – It comes from the ancient Greek word októpous, whose plural is októpodes. Although octopodes is technically correct, since it has been adopted into the English language, the word is now pluralized in the English way, making it octopuses. So octopi is commonly used but not technically correct, octopodes is technically correct but not commonly used and octopussies is just plain wrong.

2. Octopuses are mollusks. This means that they are not only closely related to squid and cuttlefish, but also to clams, oysters, snails and slugs.

3. Octopuses are crazy-smart. They can solve problems, learn from watching others, use tools, and remember experiences. They even have personalities and play with toys. Check this out:

4. Octopuses have nine brains! Rather than a large centralized brain like ours, octopus brains are more like the internet. Their main CPU is a fairly small brain in their head, but each of their eight arms has an additional brain of its own. In fact, two-thirds of an octopus’ neurons are in the arms, which can independently attach to things, push things, and even smell things. They can even react after they have been severed! Not only that, but their severed arms recognize their previous owner:

5. If an octopus loses an arm, it can grow back. Those crazy arms are like the brooms in Disney's Sorcerer's Apprentice in Fantasia!

6. Octopuses are amazing camouflage artists. Their soft bodies can squeeze into ridiculously small cracks and crevices and take on any number of shapes. A 50-pound octopus, for example, can squeeze through a 2-inch hole! They can also change the color and texture of their skin to match their background.

The mimic octopus, the ultimate master of disguise, doesn’t just imitate their background, but also flounders, starfish, poisonous lionfish, and sea snakes.



A vertebrate eye (left) versus an octopus eye (right).
1: Retina, 2: Nerve fibers, 3: Optic nerve, 4: Blind spot.
Image by Jerry Crimson Mann at Wikimedia.

7. Octopuses don’t have visual blind-spots. Most animal eyes detect light patterns when light travels to the retina (the layer in the back of the eye) and falls on photoreceptor cells, causing the cells to send electrical signals through the optic nerve to the brain. Vertebrate photoreceptor cells face backwards, so their nerve fibers come in front of the retina and then exit the eye together through the optic nerve, creating a small region in the back of the eye with no photoreceptor cells. If light falls on this spot, we literally will not see it, although our brain will compensate for this missing light by imagining what should be there based on the rest of what we see. We call this our blind spot. You can test your blind spot by closing your left eye and focusing your right eye on the “R” below. Move your face towards or away from the screen until the “L” disappears. You can test your left eye by staring at the “L” in the same way.

In octopus eyes, the photoreceptor cells face forwards and the nerve fibers go behind the retina. This means that they have a continuous layer of photoreceptor cells and no blind spot.

8. Octopuses are more blue blooded than police officers. Their blood is truly blue, due to the fact that they don’t have hemoglobin, our respiratory pigment that contains iron and turns red when it binds to oxygen. Rather, they have hemocyanin, which contains copper and turns blue when oxygen binds to it.

9. Octopuses have three hearts! They have two small hearts that each pump blood through the gills and a main systemic heart that collects the blood and pumps it through the circulatory system.

10. Octopus ink is a defensive chemical concoction. It not only obscures the view of an attacker, but it also contains a chemical that irritates the predator’s eyes and temporarily paralyzes its sense of smell.

11. Octopuses bite with a bird-like beak and venomous saliva, which is mostly used to subdue prey. Of the approximately 300 octopus species, only the small blue-ringed octopus is known to be deadly to humans.

12. Octopuses die after they mate for the first time. And they mate in an odd way too: males use the tip of their third arm on the right to either insert their spermatophores (sperm packets) directly into the female’s tubular breathing funnel or he just hands it to her (The tip of the third right arm can be used to tell if an octopus is male or female). If he hands it to her, she accepts it with one of her right arms (we don’t know why they’re right-handed this way). Then the males go off to die. The females eventually lay up to 400,000 fertilized eggs, although they can wait months before they do this. She tends them and guards them at the exclusion of all else until they hatch, at which point her body rapidly deteriorates as her cells die off.

Caught in My Web: Creepy Animals, Animal Disguises, Pet-Love After Death, and Ebola

For this Halloween edition of Caught in My Web, we check out what the web has to say about creepy animal stories.


1. The CDC addresses questions about whether pets can get ebola

2. Julie Hecht, the author of Dog Spies at Scientific American blogs explores the love between dogs and their owners from beyond the grave

3. BuzzFeed presents 8 surprisingly creepy animals.

4. Dr. Doolittle at ScienceBlogs talks about the eyeless Mexican cavefish

5. Sara Mynott at Saltwater Science, a blog at Nature’s Scitable blog network, explains flounder disguises (they’re not just for Halloween)

The Mimic Octopus: Master of Disguise

The disguises of the mimic octopus: (a) shows a mimic
octopus looking out of its burrow; (b) is a foraging mimic
octopus with coloration to blend with the sand; (c) shows
a mimic octopus as a sole fish and (d) is an actual
sole fish; (e) shows a mimic octopus as a lion-fish and
(f) is an actual lion-fish; and (g) shows a mimic octopus
as a banded sea-snake and (h) is an actual banded
sea-snake. Images from the Norman, 2001 article
 in Proc. R. Soc. Lond. B.

Different animal species have evolved a number of ways to hide in their environments. One of the most popular tactics is by camouflage, often by matching the background or by having patterns that break up the animal's outline (think: zebras and leopards). Others have evolved to resemble other species that are generally toxic or venomous, in a technique called mimicry. But a few amazing species have been recently discovered to have the ability to alter their mimicry to actively imitate a range of species, depending on their circumstances. The most remarkable of these is the mimic octopus, which shifts its shape and behavior to mimic a number of different species as fluidly as a real-life Mystique from the X-Men.

This week at Accumulating Glitches I talk about the remarkable acts of mimicry by one of our planet's most fascinating species, the mimic octopus. Check it out here.

And to learn more, check these out:

1. Norman, M.D., Finn, J., & Tregenza, T. (2001). Dynamic mimicry in an Indo-Malayan octopus Proc. R. Soc. Lond. B,, 268, 1755-1758 DOI: 10.1098/rspb.2001.1708

2. Hanlon, R.T., Conroy, L., & Forsythe, J.W. (2008). Mimicry and foraging behaviour of two tropical sand-flat octopus species off North Sulawesi, Indonesia Biological Journal of the Linnean Society, 93, 23-38 DOI: 10.1111/j.1095-8312.2007.00948.x

Nature’s Halloween Costumes

Image by Steve at Wikimedia Commons.

It seems like everyone is racking their brains to come up with a great Halloween costume. But we’re not the only ones to disguise ourselves as something we’re not. Many animals put on costumes just like we do. Take this gharial crocodile for example (do you see him?), covering himself in parts of his environment to hide.

Other animals, like this tawny frogmouth below, develop physical appearances that help them blend in with their surroundings. When threatened, these birds shut their eyes, erect their feathers and point their beak in such a way to match the color and texture of the tree bark.


Image by C Coverdale at Wikimedia Commons.

Rather than hide, some animals have a physical appearance to disguise themselves as other species that are often fierce, toxic or venomous. This type of mimicry is called Batesian mimicry, named after Henry Walter Bates, the English naturalist who studied butterflies in the Amazon and gave the first scientific description of animal mimicry. This plate from Bates’ 1862 paper, Contributions to an Insect Fauna of the Amazon Valley: Heliconiidae, illustrates Batesian mimicry between various toxic butterfly species (in the second and bottom rows) and their harmless mimics (in the top and third rows).


This plate from Bates’ 1862 paper, Contributions to an Insect Fauna of
the Amazon Valley: Heliconiidae is available on Wikipedia Commons.

The bluestriped fangblenny takes its costume another step further, by changing its shape, colors, and behavior to match the company. This fish changes its colors to match other innocuous fish species that are around so it can sneak up and bite unsuspecting larger fish that would otherwise bite them back! Learn more about them here.

The fish on the far left is a juvenile cleaner wrasse in the act of cleaning another fish. The two fish in
the middle and on the right are both bluestriped fangblennies, one in its cleaner wrasse-mimicking
coloration (middle) and the other not (right). Figure from the Cheney, 2013 article in Behavioral Ecology.

But the Master of Disguise title has got to go to the mimic octopus. This animal can change its color, shape and behavior to look and behave like a wide range of creatures, including an innocuous flounder, a poisonous lionfish, or even a dangerous sea snake! Check it out in action:

Did that Rock Just Ink on Me? (A Guest Post)

By Sam Brunner and Ian Straus

Image from NOAA.

Cephalopods, like octopuses, squid, and cuttlefish, are well known for their ability to alter the color and patterns on their bodies for better camouflage, mimicry, and even communication. By developing a unique set of camouflage tools, cephalopods excel at not being seen or being seen but not detected as a cephalopod. There are videos all over the internet showcasing how squid can terrify divers with their flashing red displays, or how some octopuses avoid their predators by mimicking the local venomous snakes. This video provides the perfect example of an octopus using its incredible camouflage to become invisible while convincing you it is merely a clump of algae.

You see, where many animals have lowly organelles in their skin cells responsible for pigments, cephalopods are unique in having a whole organ dedicated to this task. They’re called chromatophores. Each chromatophore is made up of colored pigment granules held in the ever so eloquently named cytoelastic sacculus, which is surrounded by 15 to 25 radially arranged muscle cells (like spokes on a wheel). Each muscle cell is also associated with a neural axon and its supportive glial cells, which puts it under the control of the nervous system.

Image created by Ian Straus.

So, when an octopus wants to change color, a signal travels from the brain and down the neural axon to the chromatophore, telling the muscles to contract. The muscle contraction pulls on the pigment-filled sac, stretching it to change its translucence and thereby changing the amount of color showing through. The chromatophores can produce yellow, orange, red, brown, and occasionally black pigments. The intensity of the color depends on how many muscle fibers are contracted, and therefore how much the sac expands and the pigment is spread out. Once a chromatophore develops, it will stay put for the rest of the animal’s life. As the animal grows, new, smaller chromatophores develop in the spaces between the old ones. These new organs are only able to produce yellow pigment at first, but darken as they get older.

Dieter Froesch of the Zoological Station of Naples conducted an experiment using the common octopus (Octopus vulgaris) to determine which of their nerves control the chromatophore organs in each part of the body. Each octopus examined was anaesthetized, had a nerve cut and was then checked a few days later for the results.

Froesch found that of the thirty nerves leaving the brain of O. vulgaris, ten have control over chromatophores, with each nerve controlling a different region of the body. These regions have well defined borders with no overlap. The head region alone is controlled by five different nerves, especially around the eyes. This suggests that fine control over color patterns around the eye may play an important role in effective camouflage. Furthermore, the coloration and chromatophores in one area of the body, the funnel, didn’t appear to be controlled by any of the nerves cut in this experiment.



This image shows the different chromatophore regions that each nerve controls. The funnel, which does not have nerve-controlled chromatophores, is the tube near the eye. Image is from Froesch’s Marine Biology paper (1973).

In most cephalopods, vision is the most important sense. Information about their surroundings is processed in vision regions of the brain, which then send along information to chromatophore regions of the brain. The chromatophore brain regions, which contain motor neurons, send signals to the chromatophores throughout the body telling them to contract. So, if an octopus sees a bright orange coral structure, the chromatophores will contract in a way that results in bright orange skin being displayed.

The vision-chromatophore pathway may be the most important part of cephalopod camouflage, but it isn’t the only set of structures that play a role. Leucophores allow for white pigment and reflective iridophores are responsible for blues and greens. Cuttlefish and many octopuses also have muscles throughout the skin arranged into papillae, which can form bumps or spikes that transform the texture of the animal into that of seaweed or an inconspicuous rock. In Octopus vulgaris, all these components are arranged into 1 mm wide units distributed across the skin, with the leucophores and iridophores in the central region, papillae at the exact center, and chromatophores distributed throughout. This complex physiological system grants cephalopods the greatest array of possible camouflages and firmly positions them as the coolest of the invertebrates.

Want to know more?  Check these out:

1. Froesch, D. (1973). Projection of chromatophore nerves on the body surface of Octopus vulgaris Marine Biology, 19 (2), 153-155 DOI: 10.1007/BF00353586

2. Messenger JB (2001). Cephalopod chromatophores: neurobiology and natural history. Biological reviews of the Cambridge Philosophical Society, 76 (4), 473-528 PMID: 11762491