Polar Bear (Ursus maritimus)

It’s hard to believe I haven’t written about polar bears yet. I think partly it’s because I try and focus on more obscure animals, but still, polar bears definitely deserve their own blog post. It worked out especially well for today because I was looking for an animal to draw with white pencil on black paper, and polar bears fit perfectly.

In case you didn’t know, polar bears live in polar regions, specifically in the Arctic. They are found in Greenland, Norway, Russia, Alaska, and northern Canada. Polar bears are actually considered marine mammals, as they spend much of their time at sea. They are also known for travelling great distances over land, as ice melts and then reforms.

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The range of polar bears around the Arctic. Image source: Wikipedia

Polar bears are some of the biggest bears in the world; their only competitors being Kodiak bears, a subspecies of brown bear. Male polar bears are quite a bit larger than females, weighing an average of 385 to 410 kg, while females weigh only 150-250 kg. The largest polar bear ever recorded weighed an astounding 1,002 kg. Polar bear fur appears white or yellowish, but is actually transparent and hollow, the white colour a result of refracted light.

I don’t think living in the Arctic would be much fun, but polar bears are wonderfully adapted to their frigid environment. Their skin is black, to absorb as much heat as possible from sunlight. Like most animals that live in cold climes, polar bears have small ears and tails, so as little heat is lost through them as possible. They have two layers of fur for insulation, and an additional 10 cm layer of fat that helps them keep warm. All these adaptations mean polar bears don’t do well in warm weather — in fact they start to overheat at temperatures above 10 degrees celsius.

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A polar bear swimming. They use their fat to float and then ‘dog paddle’ through the water. Image source: Wikipedia

Polar bears are also excellent swimmers. They have extra large feet that are used to propel the bears through the water, as well as distributing weight while the bears are walking on snow or ice. Their feet have small bumps on them to increase grip on ice. Polar bears’ thick layer of fat is also useful when they are swimming, as it provides buoyancy. Polar bears can swim for days on end, moving at 10 km/h.

Polar bears are meat eaters, and are in fact the most carnivorous members of the bear family. They feast primarily on ringed and bearded seals. The bears hunt seals when they come to air holes in the ice to breathe, or when seals pull themselves out of the water to rest. Using their excellent sense of smell, polar bears are able to locate seal breathing holes from 1.6 km away. A bear will wait by the breathing hole, sometimes for hours, until a seal comes up to breathe. When a poor seal does show up, the bear reaches in and drags the seal out with its paw.

Adult polar bears will often only eat the skin and blubber of the seal, which are digested easily and are calorie-dense. Younger bears can’t afford to be as picky, and will eat the meat of the of the seal as well. Polar bears do attack land animals as well, though seals remain the most important part of their diets. During the summer, when there is no pack ice for the bears to hunt from, polar bears are food-deprived, as they cannot get enough calories from non-seal food sources.

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A polar bear navigating the ice. Image source

Mating in polar bears takes place in the spring, in April or May. Group of bears will gather around good hunting spots, and males will fight for the right to breed with females. Once a male and female have paired up, they stay together and mate for about a week. Fertilized eggs have their development suspended until the late summer. During this time, female polar bears eat and eat, generally doubling their body weights.

Females dig a maternity den in the fall, in snowdrifts or underground. They enter a hibernation-like state until the young are born, in November to February. At birth, polar bear cubs are blind and weigh around 600 grams. Litter sizes range from one to four, though litters of two cubs are the most common. The family emerges from their den between February and May. At this time the cubs weigh between 10-15 kg. They stay with their mother for two to three years, learning from her actions as well as through play. Mother polar bears are known to be excellent guardians, and are very protective of their offspring. So don’t ever get between a polar bear mother and her cubs!

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A mama polar bear and her cub. Image credit: AWeith via Wikipedia

Despite their size and carnivorous nature, polar bears will generally choose to flee rather than fight. Attacks on humans do happen, but these are driven by hunger, not due aggression from the bear. So I guess if you run into a polar bear in the Arctic, you’d best hope it had a tasty meal recently. Polar bears, of course, are the poster children of climate change, as they rely on ice packs to hunt and survive. They are currently listed as a vulnerable species, thanks to the decline ice in the Arctic. They are amazingly beautiful and wonderfully adapted animals, and hopefully we can keep them around for a while to come.

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My drawing of a polar bear cub. He’s pretty cute! 

Common Adder (Vipera berus)

I hadn’t planned on writing about adders today. But I was looking for cool pictures of rattlesnakes to draw, and came across a lovely picture of an adder’s face. Before I knew it, I had started drawing, and so the subject of today’s blog post was chosen. So it goes.

Common adders are found in a large area, from the UK in the west to the China and Korea in the East. They are notable for being found further north than any other species of snake, and are also the only venomous snake species the UK. As you can imagine for such a widespread animal, they live in many different types of habitats. They are known to inhabit woodlands, hills, moors, meadows, grasslands and wetlands. Adders do require spots suitable for sunbathing, as well as ground cover so they can hide from predators.

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The distribution of the common adder in Europe. Image source: Wikipedia

Adders are reasonably large snakes, reaching lengths of up to 80 cm. They vary in colour, and can be grey, cream, pale yellow or reddish brown. Most adders have some kind of zig zag pattern on their backs and sides, though some snakes are entirely black and so have no visible pattern at all. Female common adders tend to be bigger than males, and have more reddish colouring.

Activity in adders varies depending on their location — in the north they tend to be most active during the day, while in the southern part of their range they come out at in the evening or at night. Cold-blooded animals don’t do so well when temperatures drop below freezing, so adders in colder areas hibernate during the winter. They hibernate in groups, drawing warmth from one another, as well as from the burrows they sleep in. Even with these precautions, not all snakes survive the winter: 15% of adults and 30-40% of juveniles will not make through hibernation.

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A normal and black common adder, posing wonderfully for an awesome picture. Image source: Wikipedia

Common adders are venomous, but they aren’t particularly scary snakes. Their venom isn’t super deadly to humans, with only intense pain and swelling occurring at the bite site. It is very rare for humans to die from common adder bites, with the most vulnerable population being small children. These snakes are also quite shy — they prefer to run away rather than bite. However, they are quite common in human inhabited areas, so bites aren’t that uncommon, and medical treatment is required after each bite. On the bright side, there is plenty of antivenin available!

Their venom may not be super effective against people, but it works pretty well on the snakes’ preferred meals. Adders will either wait to ambush prey while it walks by, or actively hunt an animal using their keen sense of smell. Mice, voles, shrews, lizards, birds and frogs all fall victim to common adders. Adders themselves fall prey to foxes, badgers, and birds of prey. Their colouration helps them hide, and any potential predator does have to be wary of the snakes’ bites.

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A common adder showing off its pretty face. Image credit: Benny Trapp via Wikipedia

After spending a long winter curled up with other snakes, adders emerge in a pretty good mood. They start to mate soon after coming out of hibernation, in the spring. Male snakes wait patiently for females to emerge, and then try and convince them to engage in copulation. They do this by relentlessly following females, for hundreds of meters if need be. When they do catch up to a lucky girl snake, the males will flick their tongues along her back and lash their tails excitedly. They also have to chase away any rival males, and fights do sometimes occur.

Females give birth to three to twenty young, after a three to four month gestation period. The young snakes are fourteen to 23 cm long, and are born in a sac that they must emerge from. They also have a yolk sac that they can use for nutrients during the first few days of life. This is important, as the young snakes are independent from birth. They take three to four years to reach sexual maturity.

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My drawing of a common adder, done in charcoal. I love drawing snakes! 

Despite their large range and hefty population, adders are a protected species in some countries, such as Britain and Norway. Thanks to habitat fragmentation, human fear of the species, and collection for pets, adder populations are declining. It’s a shame because these are some lovely snakes, despite their venom. Yes, I wouldn’t want to get bitten by an adder, but the same rule applies to adders as to all snakes: leave them alone, and likely you won’t have any trouble. So don’t go pestering these pretty guys!

Cover image source: Wikipedia

Carpenter Ant (genus Camponotus)

I find writing about ants difficult. Often there’s not a ton of information at the species level, and when you look at the genus as a whole, there’s way too much information. Still, ants are some of the most incredible insects around, so I’m going to do my best with today’s post!

You’ve probably heard of carpenter ants, but did you know there are over one thousand species of carpenter ant? They are found all over the world, particularly in forested areas. Carpenter ants are so named because they build their nests in moist and decaying wood, both in trees and in manmade structures.

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This ant may look like it’s dancing, but it’s actually cleaning its antennae. Image credit: Muhammad Mahdi Karim via Wikipedia

Carpenter ants range in size, depending on the species. They can be anywhere from .76 to 2.54 cm long. Size also depends on the ants’ roles within their colonies, as some species have small and large workers, as well as ants in other roles. They also vary in colour, from completely black to a light brown.

Though carpenter ants build nests in wood, they do not eat it. Instead, they feed on plants, nectar, and on other insects or insect products, such as honeydew from aphids. Some species of carpenter ant will ‘farm’ aphids, tending to them and then living off the sweet honeydew they produce.

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A carpenter ant queen, looking quite regal. Image credit: Alex Wild via Wikipedia

Farming aphids is super cool, adding to the argument that ants are the most amazing animals on the planet. But some species have an even cooler (and grosser) method of hunting and defending themselves. These ‘exploding’ ants have enlarged glands all over their bodies, which can burst when the ants are threatened. This kills the ant, of course, but also covers the victim in a sticky substance that immobilizes it. It may seem foolish for an animal to sacrifice itself, but don’t forget that ants live for the good of the colony, and no sacrifice is too great.

Communication is key in colonial living, so carpenter ants, like most species of ant, use pheromones to send messages to the rest of the colony. Worker ants that find food will leave a trail of pheromones to mark the shortest path from the food to the nest. Other pheromones can be used to calm worker ants, or excite them so they can defend the colony. Pheromones also let ants know which ants belong to their colony and which do not.

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My drawing of a lovely carpenter ant queen. I had fun with this one!

Carpenter ants reproduce using mating flights, which occur when things are hot and steamy (literally: nuptial flights happen when the weather is warm and humid). Female ants will mate with multiple males during this flight, and then lose their wings and head out to find new places to colonize. Once the females have found a suitable spot, they lay around twenty eggs, which hatch into workers that will help her as she continues to lay eggs. Some carpenter nests have multiple queens, though they will act aggressively towards one another and therefore have to be kept in different parts of the nest.

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An example of the damage carpenter ants can do to wooden boards. Image credit: Nwbeeson via Wikipedia

There’s no doubt that carpenter ants are incredible creatures. Unfortunately, their habit of nesting in wood means that certain species of carpenter ant can be serious pests, as they nest in buildings and can cause extensive damage. Other species around the world are used as a food source, though I’m not sure I’d want to eat an ant. Still, whether you view them as pests or food, you have to appreciate the wonderful complexity of carpenter ants.

Cover image credit: Bruce Marlin via Wikipedia

Bull Shark (Carcharhinus leucas)

It’s been quite a while since I’ve written about a shark, which is a shame, because sharks are awesome. Not all sharks are created equal, however, so I thought end my shark drought by writing about a particularly fearsome species, the bull shark. Bull sharks go by a number of different names, including Zambezi sharks, Nicaragua Sharks, and cub sharks. I’m going to stick with bull shark, for simplicity’s sake.

Bull sharks have a wide range, in tropical and subtropical areas. They are mainly found in coastal areas in the world’s oceans, though they will enter estuaries, deltas, rivers and lakes. In the United Sates, bull sharks have travelled up the Mississippi River as far as Alton, Illinois. Bull sharks don’t like to swim very deep, rarely being found at depths beyond 30 meters.

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A map showing the distribution of bull sharks worldwide. Looks like I’m safe here in Canada! Image source: Wikipedia

Bull sharks have earned their name, being large, chunky, and aggressive. Female sharks are bigger than males, reaching average lengths of 2.4 m, with the largest recorded specimen measuring in at a whopping 4.0 m long. Bull sharks have short snouts, and mouths that are filled with large (and terrifying) triangular teeth. There’s good reason to stay away from a bull shark’s mouth: they have the highest bite force of all sharks, relative to body size.

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Look at those teeth! I don’t think being bitten by those would be very much fun… Image credit: D Ross Robertson via Wikipedia

There’s another reason you probably shouldn’t get into water with a bull shark — as mentioned, they are very aggressive. Along with tiger sharks and great whites, bull sharks make up the three most dangerous shark species to humans. Bull sharks are particularly deadly thanks to the wide variety of habitats they live in, as well as their penchant for hanging around in shallow waters. Because people also like to swim in shallow areas, bull sharks run into people more often than other species do. What fun!

Though bull sharks do readily attack humans, they don’t make regular meals out of them. Instead, bull sharks prefer to feed on various fish and small sharks, but will also eat turtles, birds, mammals and stingrays. They have excellent senses of smell and hearing, which they use to navigate the often murky waters they hunt in.

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I don’t know who got close enough to take this picture, but I wouldn’t want to be them! Image source: Wikipedia

Reproduction in bulls sharks occurs in summer and autumn, when the sharks swim into estuaries and river deltas to mate. Males will often bite female sharks during copulation, leaving nasty scars on their bodies. Female bull sharks give birth to live young, after almost a year’s gestation. Litters range in size from four to ten pups. The young are born in freshwater lagoons, rivers, and estuaries, and stay there until they mature.

Bull sharks are unique among sharks for being able to survive in both salt and freshwater habitats. This gives their young a distinct advantage — the little ones can hang around in the relatively predator-free freshwater areas until they’re big enough to protect themselves. Bull sharks are able to move between salt and freshwater thanks to their kidneys, liver, rectal glands and gills, all which help regulate the salinity of blood in the sharks’ bodies.

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I drew this for a special project I’m working on… hopefully you’ll hear more about it soon! 

Unfortunately, though breeding in fresh, shallow water protects the young sharks from animal predators, these areas are also those that are most affected by human development. In recent years, the number of bull sharks in estuaries has been declining, and the species is now listed as near threatened. I know bull sharks are scary and they attack people, but those attacks are quite rare, and they’re not evil enough to deserve extinction. But do be careful when swimming in shallow waters!

Cover image credit: Pterantula via Wikipedia

Eurasian Eagle-Owl (Bubo bubo)

This week I really felt like drawing eyes, so I looked around the internet for a bird with impressive eyes. It’s hard to get more intense eyes than those of a bird of prey, so I was looking mainly for some kind of eagle or owl. And then I stumbled across the magnificent eagle-owl, and I knew I’d found my blog animal for the day.

There are a number of species of eagle-owl, but I’m going to focus on the one that is most commonly referred to as just ‘eagle-owl’ — the Eurasian eagle-owl. As the name suggests, Eurasian eagle-owls are found in Europe and Asia, covering a vast range of about 32 million square kilometres. They aren’t super picky about where they live, and are found in forests, deserts, mountain ranges, farmlands, and riverbeds. Though adaptable, eagle-owls prefer rocky landscapes, which are ideal for nesting.

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The range of the eagle-owl. They certainly get around! Image source: Wikipedia

Eagle-owls are quite large, and are known for being one of the largest species of owl in the world. Their total length ranges from 56 to 75 cm, with wingspans that can reach up to two meters. These owls weigh between 1.22 to 4.6 kg, with females being larger than males. Eagle-owls are mostly brown and black, with white markings on their faces and necks. They have very noticeable ear tufts and giant, orange eyes.

These fearsome birds are quite territorial, chasing other owls and owls of their own species out of their space. They generally stay in the same territory year after year, unless food becomes too scarce or they driven away by other eagle-owls. Being owls, these guys are nocturnal, coming out to hunt at dusk and staying active for most of the night.

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A handsome eagle-owl posing for a picture. Image credit: Piotr_J via Wikipedia 

As big birds, eagle-owls are capable of hunting some fairly sizeable prey. They are known to eat rats, mice, voles, fawns, and foxes. Other prey items include various bird species, including crows, ducks and owls. Eagle owls scan for prey from perches, and then swoop down for the kill. Like other owls, eagle-owls are silent fliers, and use their excellent sight and hearing to track prey in the darkness. Most of the time prey is killed by eagle-owls’ strong talons, but occasionally a swift bite to the head is needed.

Eagle-owls are normally disturbed loners, but do pair up during the breeding season. Courtship begins in the winter, in January and February. Eagle-owls have a variety of vocalizations, used for territoriality and for courtship. Pair bonds are maintained for life, and owls go through courtship rituals each year to strengthen their bonds. Courtship involves a series of calls, bows, and rubbing against one another.

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Those are some intense eyes! 

The birds nest on rocky surfaces, usually on cliffs or slopes, though they will nest on the ground if no alternative is available. One to four eggs are laid, which are incubated solely by the female owl. Her mate does help out, though, by bringing her food during incubation. The eggs hatch after about a month, and the owlets grow very quickly, faster than any other species of owl. I suppose you have to grow quite quickly if you’re going to become one of the world’s largest owls. They will walk out of the nest at five weeks of age, and can fly for short distances at seven weeks. The young birds become independent in the fall, and are sexually mature at two to three years of age.

Eagle-owls have a large population worldwide, as well as an extensive range. Because of this, they are currently a species of least concern, which is great news. Hopefully such beautiful and amazing birds can continue to grace our night skies for years to come.

Cover image credit: DickDaniels via Wikipedia

Vampire Bat (subfamily Desmodontinae)

It’s hard not to think of vampires when you think of bats, and while many bats are harmless and helpful fruit- and insect-eaters, not all bats play so nice. There are some that embrace their vampire connections, and they are known, quite unimaginatively, as vampire bats.

There are three species of vampire bat, and each is so unique that they are placed in a separate genus (Desmodus, Diphylla, and Diaemus, for those who are interested). You can find these extra-creepy bats in Central and South America. Their preferred habitats are in tropical and subtropical areas, and they require dark places for roosting, such as caves, wells, hollow trees and buildings.

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A white-winged vampire bat. Image credt: Gcarter2 via Wikipedia 

Vampire bats are not overly large animals, with all species ranging in length from seven to nine centimetres. They have greyish brown fur, and in general, look fairly bat-like. They do not have nose leafs life fruit bats — they make do with naked nose pads with grooves in them. Vampire bats are also more suited to moving on the ground than other bat species, using their wings to propel them across the ground in a bounding gait.

You may have guessed — or already know — why vampire bats are named after the mythological Transylvanian monsters. Yes, these bats do suck blood. Common vampire bats feed primarily on mammalian blood, while hairy-legged vampire bats and white-winged vampire bats are more partial to bird blood. They feed only at night, so you don’t need to worry about being attacked by vampire bats (or vampires) when the sun is out.

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Vampire bats have distinct skulls and teeth that make feeding on blood easier. Image credit: Mokele via Wikipedia 

Subsisting solely on blood is a very specialized diet, and vampire bats have some amazing adaptations as a result. They have thermoreceptors in their noses, which are used to locate areas where blood flows close to their prey’s skin. There’s even an area in vampire bats’ brains that is similar in appearance and location to infrared receptors in snakes, as the bats are capable of using infrared to find blood on their prey.

Once the blood is located, the bats have to find a way to access it. They do this with their razor sharp teeth — teeth that lack enamel so they are always incredibly sharp. Once they slice into their poor victim’s skin, vampire bats use their saliva, which is full of anticoagulants, to keep the wound bleeding.

Vampire bats also have a special digestive system to cope with their sanguine diet. To get the nutrients they need, bats typically drink about 20 grams of blood per feeding — which is a lot for creatures that weigh an average of 40 grams. That added weight is a problem for flight animals, so the bats have to jettison some of that extra cargo before they take off and return home. Therefore, their digestive system is designed to digest the blood as soon as possible, and pass on the extra liquid to the kidneys so it can be excreted. Typically, vampire bats start to urinate within two minutes of feeding. That’s some pretty quick digestion!

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Vampire bats roosting together in a colony. On cold days, even non-resident males are invited into the colony to help keep the other bats warm. Image source

While the picture I’ve painted of vampire bats is one of evil, blood-sucking monsters, vampire bats aren’t all bad. At least, they’re nice to (most) members of their own species. Highly social animals, vampire bats live in colonies consisting groups of females and a few resident males. Non-resident males are shunned and live in separate groups.

Within colonies, vampire bats may share food with bats that are related to them, or bats that they know. A vampire bat can go only two days without feeding, so often a starving bat will beg another for food when sources of meals are scarce. The donor bat will then regurgitate a bit of blood for the beggar to consume. The exact nature of these relationships is still being studied, but it just goes to show that vampire bats are not self-serving, malicious creatures.

Vampire Bat

I had a lot of fun drawing this guy for today. I like bats! 

Vampire bats have been known to carry rabies, but it is very rare for a vampire bat to pass the disease on to humans. So don’t be afraid of these amazing animals! They are also medically useful, with compounds in their saliva being used in medicine to increase blood flow in stroke patients. See, vampires are friendly after all!

Cover image source