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.

A Master of Disguise (A Guest Post)

By Jake Klemm

Cephalopods are among the most intelligent of marine life. Their highly advanced nervous systems allow them to exhibit a complex array of behaviors (for example, camouflage). Within this array is a rather unique behavior observed in the cuttlefish Sepia pharaonis. These elegant beings are now known to… intensely flap their arms? These animals are truly graceful.

A lovely photo of S. pharaonis. Image by Silke Baron at Wikimedia Commons.

Researchers Kohei Okamoto, Haruhiko Yasumuro, Akira Mori, and Yuzuru Ikeda of the University of the Ryukyus in Okinawa, Japan observed this behavior on two separate occasions while studying S. pharaonis. The scientists had initially collected these cuttlefish with the intention of conducting other experiments but noticed this behavior while the cuttlefish were introduced to a large water-filled tank and while hunting prey. After noticing this wild arm-flapping behavior, the researchers turned their attention towards why the behavior was being displayed.

The researchers first observed this behavior in December of 2011. The cuttlefish were placed in a large, circular tank for conducting other experiments when a couple of them were observed to flap their arms. After the initial experiments were finished, a few of the cuttlefish were placed in the same sized tank and observations were recorded with a video camera over a period of five days. This behavior was revisited in 2013 for further observation. The cuttlefish they used were reared from eggs found in the same coastal waters of Okinawajima Island as the cuttlefish that were part of the 2011 experiments. Again, cuttlefish were placed in a large tank to observe the behavior with a video camera. The researchers counted each occurrence of the behavior and recorded the duration of each behavior. After observations were complete, the researchers performed experiments to observe the hunting ability of S. pharaonis. This arm-flapping behavior was observed unexpectedly while the cuttlefish hunted prey. The means of recording the behavior were the same as described above. In addition, the researchers recorded the number of prey caught between cuttlefish that did and did not display the behavior.

The researchers noticed variation in the frequency and duration of this behavior in the presence and absence of prey. When placed in a tank without prey, only a small number of cuttlefishes displayed this behavior. Of the cuttlefish that did flap their arms, the behavior lasted (on average) no longer than 37 seconds. However, the cuttlefish that were placed in a tank with prey, the behavior was displayed for at significantly longer period of time. In addition to that, more cuttlefish overall were seen flapping their arms in this second experiment. The cuttlefish that flapped their arms caught a significantly larger number of fish than the ones that did not flap their arms, despite being observed in the same tank and having access to the same number of prey animals. This observation led the researchers to believe that something about this unique behavior is helping the cuttlefish capture more prey.

A front view of a cuttlefish. Image by Stickpen at Wikimedia Commons.

The resemblance is uncanny! Image by Maximilian Paradiz at Wikimedia Commons.

What could this all mean? The researchers think that the cuttlefish may be mimicking another organism, specifically the hermit crab, to confuse the prey fish into thinking that they are another harmless animal. It is thought that the head of the cuttlefish resembles the shell of the hermit crab while the arms resemble the eyes and legs of the hermit crab. Posing as a harmless crab would allow the cuttlefish to get behind enemy lines and ultimately catch more prey. Further research will have to be done in lab as well as the field to see if this behavior is really that of mimicry. Other cephalopods are notorious for mimicking other animals, so it is not out of the realm of possibility. Studying this behavior would allow scientists to difurtveher into the evolutionary history of S. pharaonis. Until then, the graceful limb-flailing will remain an ever-tantalizing mystery.


References

Okamoto, K., Yasumuro, H., Mori, A., & Ikeda, Y., (2017). Unique arm-flapping behavior of the pharaoh cuttlefish, Sepia pharaonic: putative mimicry of a hermit crab. Journal of Ethology, 35(3), 307-311. DOI: 10.1007/s10164-017-0519-7

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:

Caught in My Web: Mind-Altering Substances

Image by Luc Viatour at Wikimedia Commons

Drunken birds have gone viral this week! For this edition of Caught in My Web, we wonder if animals alter their mental states like people do.

1. Drunk Minnesotan birds are flying into windows! At least that is what the viral story says. But the truth may be a bit more measured. As the Police Chief of Gilbert, Minnesota says, “It sounds like every bird in our town is hammered, and that’s not the case.” Read the real story here.

2. But do wild animals really drink alcohol? Not in the way that we do, maybe, but many consume overly fermented fruits. Some have developed a tolerance to the high alcohol content, others, not so much. Just ask this poor drunk moose that got herself stuck in a tree after eating too many fermented apples.

3. But it’s not just fermented fruits that get animals drunk. Some fish can make their own alcohol to help them survive a long winter under the ice.

4. What about the effects of other mind-altering substances on animals? Ever wonder what kind of web a spider would make on different drugs? In 1948, a zoologist at the University of Tubingen in Germany by the name of H.M. Peters did.

5. Octopuses are normally very solitary creatures… that is, unless they are given ecstasy. Apparently, even octopuses seek social interactions when they take the common party drug.

Where the Wild Things Are: Amazing Animal Watching Vacations

A modified repost of an original article from May, 2012.

School is winding down, the weather is beautiful and it is time to start thinking about summer vacation! Do you love watching and learning about animals? Then consider one (or more) of these animal watching vacations:


Go to a zoo:

Get a great view of a Siberian tiger at the Toronto Zoo.
Photo by Ber Zophus at Wikimedia.

Zoos allow you to explore the world in a single day: Meandering paths lead you past animals from across the globe. Lions, and tigers and bears, Oh my! But don’t forget the primates, reptiles, birds, and sea mammals. No matter what your animal fancy, you can likely see it at the zoo. Walk through the zoo reading the posted information on each species. Or sit at your favorite exhibit and focus on a single animal. Participate in an educational activity like touching and feeding animals with their keepers, a course, or even a sleepover. And while you are there, learn about how the zoo contributes to animal well-being: Many zoos provide research opportunities to study animal behavior and health (such as the friendship study in crested macaques), support captive breeding programs to restore threatened wild populations, rehabilitate injured or abandoned wild animals, and support habitat conservation.

If you have a local zoo, see what it has to offer. And if you like to travel, consider the San Diego Zoo, the Smithsonian National Zoological Park in Washington, DC, the Singapore Zoo, the National Zoological Gardens of South Africa, or the Toronto Zoo. All of these zoos are well-respected institutions that promote animal conservation and have fantastic educational programs.

Learn more about some of these zoos here.


Go to an aquarium:

Interact with dolphins at the National Aquarium.
Photo by the National Aquarium at Wikimedia.

Aquaria are places of wonder and tranquility. Learn about teleost fish, sharks, rays, crustaceans, octopuses, jellyfish, coral, and many more species that inhabit our oceans, lakes, and rivers. Relax while watching the graceful movements of sea animals and marvel at the agility of apex predators at feeding time. Learn about the many aquatic habitats our planet supports and the amazing diversity of the animals that live in them. Like zoos, aquaria provide research opportunities (such as the individual recognition study in octopuses), support conservation, and have fun educational programs and activities.

If you get a chance, you may want to check out the National Aquarium in Baltimore, the Georgia Aquarium, the Monterey Bay Aquarium, the Aquarium of Western Australia (AQWA) in Perth or L’Oceanogràfic in Valencia, Spain.

Learn more about some of these aquariums here and here.



Take a wildlife tour:

See breathtaking animals in their natural habitat
from the security of your guide's vehicle.
Photo by Brian Snelson at Wikimedia.

If you want to see wild animals in their natural habitats, experienced guides can help you find animals that are often elusive while keeping you safe and preserving animal habitats. Guides can give detailed information about the animals you encounter and can often tell thrilling tales of their own personal experiences. Some even provide lunch.

Maybe your dream has always been to go on an African safari. Consider the Safari Serengeti trip in Tanzania by Overseas Adventure Travel, where you can see animals like Thomson’s gazelles, buffalo, and elephants. Or participate in a North American safari in Yellowstone National Park with Wolf & Bear Safaris by the Yellowstone Safari Company. If a Northwoods flavor suits you, check out Northwoods Outfitters Moose Wildlife Safari in Maine. Or take a Hawaiian vacation and go whale watching with Ultimate Whale Watch in Maui. For a scientific marine vacation, go on an Educational Shark Encounter trip with Fish Finder Adventures based in Ocean City, Maryland. Whatever your dream animal watching trip, a guide can help you bring it to life.


Go somewhere wild on your own:

Kayak by thousands of birds in the Everglades
(but don't forget your anti-bird-poop-hat).
Photo by Matt Magolan.

If you are an independently minded and experienced adventurer, the world is awaiting. And if you want to increase your chances of observing spectacular wild animals in nature, you should go somewhere that has a lot of spectacular wild animals… like Manuel Antonio Park in Costa Rica, where you can see four monkey species, two iguana species, two sloth species, coatis, toucans, vultures, parakeets, and hundreds of other species on a single hike. Or kayak in the Everglades National Park in Florida, where you can see crocodiles, dolphins, manatees and over 350 species of birds. Or SCUBA or snorkel the coral reefs of the Cayman Islands and feel like part of the community of coral, sponges, tropical fish, rays, sharks, and sea turtles.

Learn more about some of these trips here.


We share this world with countless amazing animals. Find your own way to experience, learn about and appreciate them. I’ll go into more detail on these vacations and others in future posts, so comment below and let us know what animal watching vacations you have done and what you are interested in doing in the future.

But for now, I will be going on my own vacation. Don't worry, there will be new The Scorpion and the Frog articles about animals in July!

The Best Moms in the Animal Kingdom

Moms are really important to life on Earth, as evidenced by the fact that maternal care is fairly common across the animal kingdom. In most species, females produce fewer, larger, and costlier eggs than males do sperm. Therefore, it is usually beneficial to females to maximize the possible success of each one, sometimes by gestating them inside their own bodies (as mammals do), or incubating the eggs until they are ready to hatch (as birds do), or by providing prolonged protection, food and training until they are ready to take on the world for themselves. But there is still a lot of variation in how and how much each mother gives to her offspring. Here are some of the best moms in the animal kingdom:

1. The Endurance Prize goes to orangutans: Orangutan infants cling to their moms’ bellies non-stop for the first four months of their life and they continue to completely depend on their moms for the first two years for food and transport. Their moms will continue to carry them often until they are five and will sometimes continue to breastfeed them until they are eight! After that, the young still stay close to mom, learning from her and helping her until they are sometimes in their teens.

An orangutan mama and toddler. Photo by Mistvan at Wikimedia Commons.

2. The Provider Prize goes to the crab spider, Diaea ergandros: These crab spider moms create a brood chamber and nest out of eucalyptus leaves. They guard their eggs and then spiderlings, providing protection and prey for food. These moms also make extra eggs, just for their babies to eat, and finally, they give themselves… quite literally! The babies eat their mothers completely in a rare behavior called matriphagy.

3. The Pregnancy Prize goes to elephants: Elephants are pregnant for about 22 months… nearly two years! And a baby elephant is not light to carry around… by the time it is born, it will weigh nearly 250 pounds! Just the thought of it makes me uncomfortable. So why would elephant moms need to gestate their young for such an incredibly long time? It is thought that the long gestation is needed for the proper development of their brains, so they are born with the complex cognitive and social skills needed to survive in their herd.

An African elephant family plays in the hot sun. Photo by Bernard Dupont at Wikimedia Commons.

4. The Brooding Prize goes to a deep-sea octopus: Two years is a very long time to carry a developing baby inside your body, but some animals care for their developing empryos ouside of their bodies with a behavior called brooding. Although brooding may sound easier than pregnancy, it is not for the faint of heart. A deep-sea octopus was observed brooding her eggs in the Monterey Submarine Canyon off central California for 53 months… That is nearly 4 and a half years! And that whole time she did not eat, but instead guarded and aerated the water around her precious eggs.

A deep-sea octopus. Photo by NOAA at Wikimedia Commons.

5. The Multi-Generational Prize goes to humans: Many human moms are not only good mothers, but also good grandmothers. Grandparenting is extremely rare in the animal kingdom (the first documented case of grandparenting in non-humans was as recent as 2008) and human females excel at it. They provide care, advice, resources, lessons and hugs to increase the success of their offspring and grand-offspring… It’s amazing other species haven’t picked up on this amazing secret yet!

The best moms in the animal kingdom. Photos by Sarah Jane Alger.

Caught in My Web: Perplexing Animal Behaviors

Image by Luc Viatour at Wikimedia Commons.

Sometimes animals behave in such an odd manner, that even the animal behaviorists aren't sure what the heck they are doing or why. So for this edition of Caught in My Web, we just wonder.

1. Last month, a dog was hit and killed by a car. His fellow doggy-companion then used his nose to bury him. Was this a funeral? Is this just canine burying behavior? We don't know, but it's been seen before. This video is from 2013:

And here is another from 2015:

2. Have you seen this video of turkeys circling a dead cat?

3. An African elephant approaches a white rhino with a branch across his nose. Was he trying to play or was he bring aggressive? Either way, the rhino wasn't taking any chances. Watch the exchange here.

4. A South American Magellanic penguin swims 5,000 miles every year to be reunited with the man who saved his life. Read the heartwarming story here.

5. An octopus inflates itself like a giant balloon across the ocean floor and scientists can't agree if it is hunting or showing defense behavior. What do you think?

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.

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:

Do Animals Have Personalities?

Leaders and followers. What makes personality? Photo by Thang Nguyen at Wikimedia Commons.

The heart of science lies in existential questions such as "Who am I?" and "Where did I come from?" Yet somehow, these are the very questions that scientists tend to shy away from. It's as if we're afraid that by unraveling the mysteries of our world and ourselves, we'll be left with nothing but a handful of yarn. But many of us see the quest for personal understanding differently - as a journey to gain appreciation for all the complexities and rare events that came together to weave the glorious tapestry that is life. It is in this push and pull of wanting to know more while still wanting to maintain mystery that the study of personality lies. And for this reason (and many others), the science of personality has been woefully understudied and underappreciated.

This week I am at Accumulating Glitches pondering personality: What is it? How do we study it? And do other animal species have it? Check it out here.

And to learn more, check these out:

1. Réale, D., Reader, S., Sol, D., McDougall, P., & Dingemanse, N. (2007). Integrating animal temperament within ecology and evolution Biological Reviews, 82 (2), 291-318 DOI: 10.1111/j.1469-185X.2007.00010.x

2. Huntingford, F.A. (1976). The Relationship between anti-predator behavior and aggression among conspecifics in the three-spined stickleback, Gasterosteus aculeatus Animal Behaviour, 24, 245-260

3. Sinn, D., Moltschaniwskyj, N., Wapstra, E., & Dall, S. (2009). Are behavioral syndromes invariant? Spatiotemporal variation in shy/bold behavior in squid Behavioral Ecology and Sociobiology, 64 (4), 693-702 DOI: 10.1007/s00265-009-0887-2

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