Pangolin (family Manidae)

I find it quite shocking that I have not written about pangolins yet. These guys are some of my all-time favourite mammals, and yet I’ve ignored them for nearly four years of blogging and over four hundred posts. I know I’ve considered writing about them, but perhaps the time was never quite right. Well, today is the big day for pangolins, because these amazing animals are going to get their very own blog post!

There are eight species of pangolins, all of which belong to the family Manidae. Pangolins can be found in Africa, India and southeast Asia. All species live in tropical areas, though they differe in their lifestyle choices, with some being arboreal and some preferring to live on the ground. Most pangolins are nocturnal, with only one species, the long-tailed pangolin, being active during the daytime.

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A map showing the distribution of pangolins in Africa and Asia. Image credit: Craig Pemberton via Wikipedia

Pangolins vary in size depending on the species, ranging from 30 to 100 cm long. The most notable feature of pangolins is their overlapping scales that look extremely out of place on a mammal. These scales are made of keratin, and harden as the animal matures. They may look funny, but the scales provide pangolins with an excellent mode of defence. When a pangolin feels threatened, it curls up into a ball, tucking its head under its tail, leaving the predator with only a hard, spiky ball to look at.

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This pangolin seems to have stumped these lions with his ‘curl-in-a-ball’ defence. Image credit: Sandip Kumar via Wikipedia

Pangolins are at home in a number of different environments. They happily climb trees, with some species of arboreal pangolin having prehensile tails that they can use while climbing. Ground dwelling pangolins dig burrows, which can reach depths of three and a half meters. Some species of pangolins will walk with their front claws folded under their feet, and others will sometimes rear up and perform some behaviours bi-pedally, even walking on two legs for small periods. But climbing, digging and walking aren’t the only things pangolins can do; they can also swim quite well. That’s pretty impressive for such awkward looking animals.

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A Sunda pangolin showing off its climbing skills. Image credit: Piekfrosch via Wikipedia

So what do these strange and wonderful animals eat? Pangolins like to feast on tasty and nutritious insects. They use their strong claws to dig up bug nests in trees and on the ground, and then stick out their tongues to gobble them up. Pangolins have incredibly long tongues, which are coated in saliva from glands in the animals’ chests, making them extra sticky, and thus the perfect insect grabbers. Though insects are tasty, they are small, so pangolins have to eat a lot of them. They eat between 140 to 200 g of food a day, and are quite picky, generally eating only one or two species of insect.

Another weird thing about pangolins: they don’t have teeth. They get around this by having a very muscular chamber in their stomachs, complete with spikes that help grind up food. Pangolins will also swallow stones or pebbles that assist in grinding up any food they eat.

Pangolins live solitary lives, coming together only to reproduce. There is no set mating seasons, and pangolins usually mate once a year. Pangolins are a little backwards when it comes to mating — instead of males heading out to find mates, females are lured to spots marked by male pangolin urine or dung. There is some competition over females; when this occurs male pangolins establish dominance by swinging their tails at one another.

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A little baby pangolin riding on its mama’s tail. Image source

Gestation in pangolins ranges from 70 to 140 days. Litter size depends on the species, and can be one to three baby pangolins. When they are born, the scales of young pangolins are soft (imagine giving birth to a baby armoured with spiky scales!), and these harden after several days. While the scales are still soft, mother pangolins are very protective of their young, wrapping themselves around their babies if they feel threatened. After a few weeks the young pangolins ride around on their mother’s tails, and they are weaned at around three months of age. They become sexually mature at two years of age.

There is, of course, a sad side to the pangolin story. They are hunted for their meat and their scales, as pangolin meat is considered a delicacy in many areas, and their scales are thought to have medicinal qualities. Pangolins have the upsetting title of being the Most Illegally Trafficked Animal in the world. All pangolin species are currently threatened, and two are listed as critically endangered. Though they are protected species, illegal trafficking remains a serious threat to the pangolin population. On that sad note, I’ll leave you with a cute drawing of a baby pangolin.

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A quick little sketch I made of a pangolin. So many scales to draw! 

Cover image source

Zebrafish (Danio rerio)

Usually I pick animals for this blog because they look funny, or they have a silly name, or because there’s something really super special awesome about them. Today’s animal is a bit different, because although it is quite an incredible creature on its own, many of the most amazing things about it are the results of human experimentation.

Zebrafish are found in parts of India, Pakistan, Bangladesh, Myanmar and Nepal. They have also been introduced to some areas of the US and Colombia, inadvertently and on purpose. They are freshwater fish, and are generally found in slow-moving, shallow waters. They can live in rivers, streams, floodplains, and rice fields.

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A wild-type zebrafish. Image source

Human disturbance is detrimental to many species of animals, but there are always a few that can cope or even benefit from human-changed habitats. Zebrafish are one of these lucky species, as they don’t seem to mind areas that have been altered because of rice cultivation. Growing rice often means waterways are dammed and irrigation systems are created, and zebrafish can be found in both of these altered ecosystems.

Zebrafish are quite small, innocuous fish. They can reach massive lengths of 6.4 cm, though sizes are more commonly a much more reasonable 2.5 cm. Zebrafish get their name from the stripes that run down their sides; each fish has five to seven blue stripes. Male zebrafish have gold colouring between their blue stripes, while females are silver-coloured.

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I decided to try something a bit different for this post. Not sure how I feel about the fish, but I like the way the background turned out! 

Breeding in zebrafish occurs during the monsoon season, from April to August. The fish get pretty excited about the chance to mate, rising at dawn to start courting one another. Male zebrafish follow a female around, each of them trying to lead her to a spawning site. They do this by nudging her and swimming in circles around her, which must get extremely annoying. Once a pair has reached an appropriate site, they line up their genital pores and the female releases her eggs, and the male releases his sperm.

The fertilized eggs hatch after two to three days, with all hatchlings being female. Differentiation between the two genders starts to occur at five to seven weeks of age, though males need about three months for their testes to develop completely. What causes fish to become female or male is not yet known, though it is thought that food supply and growth rates influence gender. Slow-growing zebrafish grow up to be males, while faster growing ones become females.

Zebrafish, while seemingly simple and nondescript fish, have incredible regenerative powers. While they are still larvae, zebrafish can grow back their fins, heart, brains, and retinas. These abilities have been the subject of intense research, with possible applications in human medicine being explored.

Regeneration isn’t the only trait that makes zebrafish useful research subjects. They are hardy fish, with short lifespans and large clutch sizes, making them ideal for genetic studies. They were one of the first vertebrates to be cloned, and many mutated strains of zebrafish have been created. Among the more bizarre is a strain of transparent zebrafish that glows when the brain is undergoing strong activity, and a zebrafish that turns green in waters polluted by oestrogen.

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Some GloFish… look how many colours they come in! Image source

Zebrafish aren’t just popular research animals — they are also extremely common in aquaria, especially since they come in many colours. They have even made florescent zebrafish, because why would you want a natural looking fish when you can have a GloFish®? And yes, they are actually called that.

Cover image source: Azul via Wikipedia

Red-crowned Crane (Grus japonensis)

I recently finished a book by one of my favourite authors, Simon Winchester. It was called Korea: A Walk Through the Land of Miracles, and in it, he describes his journey walking across South Korea. It was an interesting read, but the point is that he describes some of the endangered wildlife that makes its home in Korea, and the red-crowned crane caught my eye, so I decided to blog about it.

Red-crowned cranes are found in Eastern and southeast Asia. They spend their summers in Russia, China and Mongolia, migrating south to Korea and central China during the winter. There is also a non-migratory population on Hokkaido, Japan. They are found in marshes and wetlands, preferring areas with deep water, which is unusual among crane species.

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When standing, red-crowned cranes appear to have black tails, but those patches of black are actually their wings. Image credit: Alastair Rae via Wikipedia

These birds get quite big, reaching 1.5 to 1.58 meters in height, with a 2.2 to 2.5 meter wingspan. Red-crowned cranes are on average the heaviest cranes in the world, with weights ranging from 4.8 to 10.5 kilograms. The birds get their names from the red patches on their tops of their heads, which may look like feathers, but are actually areas of bare skin. The rest of the body is a mix of black and white, with black on the wings, and males having black cheeks, throats and necks.

Red-crowned cranes have long, sharp beaks. In fact, their beaks almost seem too large for their heads (that’s what I thought when I was drawing one, anyway. I had to keep checking the proportions to make sure they were right). These are used in a spearing motion to collect food. Red-crowned cranes are omnivorous, feeding  on insects, fish, amphibians, small reptiles and other birds, as well as plants and seeds. To gather food, the cranes wander through the mud, keeping their heads close to the ground. When they find something they like, the birds jab their beaks into the ground, grasping their prize in their impressive beaks.

Another benefit of that unwieldy beak that it makes an excellent weapon. The sharp beaks, along with the cranes’ enormous size, means that adult birds are quite well protected against predators. Eggs and nestlings are often the target of predators, though it takes a ballsy hunter to go after a red-crowned crane nest, as the parents will defend it aggressively, sometimes killing smaller predators that attempt the feat. Introduced mink on Hokkaido are one of the few predators that successfully raid red-crowned crane nests.

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So pretty! Image credit: Spaceaero2 via Wikipedia

Reproduction in red-crowned cranes occurs in the spring and summer. Cranes are big dancers throughout the year, but they dance a bit more during the breeding season, where pairs dance together to establish or strengthen a bond. The dances can include bows, head bobs, leaps, and calls performed in unison by both partners. Once a pair is formed, the two tend to stick together year after year.

During nesting, red-crowned cranes are territorial, and both sexes help to build nests on the ground, often on wet ground or shallow water. Females lay two eggs, which hatch after about a month. Both parents incubate the eggs and care for the chicks. The chicks leave the nest and accompany their parents on foraging trips at around three months after hatching; they fledge about 70 days after hatching. The young birds stay with their parents for a while longer, however, getting assistance from their mother and father until nine months of age. Red-crowned cranes are some of the longest-lived birds in the world, with wild birds living to 30 to 40 years, and captive birds reaching 70 years of age.

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Pencil crayon and watercolour pencil drawing of a red-crowned crane. I’m still working on the best way to scan these, so forgive the picture quality.

Unfortunately, these beautiful birds are also some of the rarest cranes in the world. There are only about 2,750 birds left in the wild. As predation is not much of an issue for this species, their main threat is the destruction of the wetlands that they live in. There is some good news. Human conflict, has, unwittingly, given some land back to the red-crowned crane and other species: the 250km long Demilitarized Zone between North and South Korea is undisturbed by people, and has become an accidental nature reserve. It gives homes to many endangered species, including the red-crowned crane. It may be an uneasy place for animals to make their homes, but at least their habitat remains undisturbed, for now.

Cover image credit: Petra Karstedt via Wikipedia

Tent Caterpillar (genus Malacosoma)

Have you ever seen trees infested with tent caterpillars? They look pretty terrible. I’ve never liked tent caterpillars – their ‘tents’ are far too much like spider silk for me to look at without shuddering. Still, I don’t discriminate, so these little guys deserve a blog post.

Tent caterpillars are the larvae of moths in the genus Malacosoma. There are at least twenty six species of tent caterpillars, found in North America and Eurasia. Different species have preferences for different host trees – for example, the eastern tent caterpillar prefers cherry and apple trees, while the western tent caterpillar is fond of oak and poplar trees.

The appearance of the caterpillars varies with species, but generally they have some variation of orange, black, white, and blue markings, with some lovely hairy bits to make them look cool. The moths themselves are pretty boring looking, being shades of brown to tan. They are also quite furry.

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A lovely ball of western tent caterpillars. Image credit: Brocken Inaglory, via Wikipedia

Tent caterpillars emerge from their eggs in the spring, and set to work building their ‘tents’ soon afterwards. The tents play a key role in keeping tent caterpillars at the right temperature. If tent caterpillars get too cold, they cannot digest any food. So the tent is designed to be a perfect heat chamber, with different layers of the tent creating a range of temperatures. To change its body temperature, all a caterpillar has to do is move from one section to another.

If warmth is the problem, why don’t tent caterpillar hatch later in the year, when temperatures are higher? Well, tent caterpillars have evolved to feed on young tree leaves, which of course grow in the early spring. When caterpillars leave the tent to forage, they leave a trail of pheromones so that they can find their way back to the tent. If a caterpillar comes across a tasty bunch of leaves, it will return to the tent and leave a different pheromone trail, which recruits other caterpillars in the tent to go on a mass feeding frenzy.

It is this feeding behaviour that can cause damage to trees, as a group of caterpillars can easily defoliate a whole tree. Generally, however, this doesn’t cause permanent damage to the tree, unless caterpillars return season after season, or the tree was already under some form of stress. Forest tent caterpillars (Malacosoma disstrium) are the species most well known for outbreaks — in a bad year (or good year, depending on what perspective you’re taking), forest tent caterpillars can defoliate tens of thousands of acres of trees.

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An adult tent caterpillar moth. Image source: Wikipedia

Tent caterpillars complete their larval growth after seven to eight weeks, after going through five or six instars. They then leave their tree and search for safe places to spin cocoons, and emerge as adults after two weeks. The life of tent caterpillar moths is not a very long one; they mate shortly after leaving the cocoons, and females die after laying eggs, meaning their life spans can be less than a day. The larvae start development in the eggs, but then pause and shelter inside their egg cases until the following spring. These are hardy little insects, being able to endure temperatures of -40 C over the winter.

I’m still not a huge fan of tent caterpillars, though the main damage they do is purely aesthetic. Still, at least I now know why they build those creepy tents, and it’s actually for a pretty neat reason. So I guess I have slightly more respect for these little creatures.

Cover image credit: Greg Hume via Wikipedia

Smew (Mergellus albellus)

A lot of animals catch my eye because of their names. Some are simply very descriptive (Northern short-tailed shrew), some are named after someone (Burton’s haplo), and some are downright bizarre (grunion). Still, I think today’s animal wins the prize for dumbest animal name ever. To me, smew sounds like a poorly thought out acronym, much like Hermione’s house elf organization, SPEW.

Despite their name, smews are actually quite beautiful birds. They are ducks, but are so unusual they are classified in their own genus, Mergellus. Smews are migratory, breeding in northern Europe and Asia, and wintering in Germany, the Low Countries, and around the Baltic and Black Seas. They like areas where there is some tree cover, especially during the breeding season, as they build their nests in tree cavities.

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A nice comparison of a male (top) and female (bottom) smew. Image credit: Andreas Trepte via Wikipedia

Male smews are very distinctive birds, having striking black and white feathering. Females are less showy, with rust-coloured crowns and grey plumage everywhere else. Smews grow to be a medium size, reaching lengths of 38-44 cm. They have special, hooked beaks with serrated edges that are perfect for grabbing fish.

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A nice close up of a female smew that shows her serrated, hooked bill. Image credit: Spinus Nature Photography via Wikipedia

Breeding season for smews begins in May, when they travel north to the taiga. As I mentioned earlier, they nest in pre-made holes in trees, often those created by woodpeckers or other animals. They lay 6-9 eggs, and fly south in early fall. During the breeding season smews tend to stay in small groups, but the rest of the year they like to be in flocks of up to 100 birds.

Although smews are fairly common in their range, their population is declining. They are protected by an international treaty, so hopefully we can keep these neat looking, weirdly named birds around for a long time (I have no idea where the name smew comes from, by the way).

Cover image credit: Dick Daniels via Wikipedia

Hoopoe (Upupa epops)

This bird caught my eye a few weeks ago, so it’s about time I blogged about it. Hoopoes have a bit of a funny name, but more importantly they are very funny looking. In fact, they are so unique that they are placed in their own family, Upupidae.

Hoopoes are Old World birds, and are found in Europe, Asia and Africa. Populations in Europe and Asia are migratory, while the African birds stay put year round. Hoopoes can use pretty much any habitat, as long as there is open ground to forage on, and nesting areas, such as cliffs, trees, or walls.

Hoopoes reach sizes of 25-32 cm, and have wingspans of up to 48 cm. They are brown on their top half and belly, with very visible white and black striped wings. Their beaks are long and thin, which helps make these birds easily identifiable. But probably the most distinctive feature of hoopoes is their large crests, which can be extended to look super silly.

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Look how dumb hoopoes look with their crests raised! Image credit: Artemy Voikhansky via Wikipedia

Hoopoes feed primarily on insects; it is for this that their long beaks are extremely useful. They forage by walking along the ground and sticking their beaks into the dirt. Their bills are extremely strong, and can be opened while in the ground, or used to move stones. Hoopoes can fly, and will sometimes pursue swarming insects in the air, but most often they stay on the ground while feeding.

Breeding in hoopoes can be quite a dangerous affair. Males violently defend their territory, and fights can result in a bird going blind. Once a pair bond is formed, it lasts for the season, but no longer. Nests are usually built in vertical surfaces, such as trees or walls. Females lay between four and twelve eggs, depending on location.

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I think they’re quite pretty, when they don’t have their crests up. Image credit: Dûrzan cîrano via Wikipedia

Once the eggs hatch, both parents are responsible for caring for the chicks. The young birds fledge after about a month, and leave their parents a week later. The young of any species are vulnerable to predators, but if I were a hungry hunter, I would stay away from hoopoe chicks. They have some very nasty ways of defending themselves.

Females who are brooding eggs produce a liquid that smells of rotting meat, and rubs this over her feathers. Once the chicks have hatched, they too produce this secretion, which scares off predators and parasites. When they are six days old, the chicks can shoot faeces at any potential predators, and can also stab at them with their long bills. The moral of the story: stay away form hoopoe nests.

Hoopoes are definitely neat birds, though I’d definitely avoid one if I met it in the wild. I’m not sure I want to smell like rotten meat or be stabbed in the eye with a sharp pointy bill. No, I’ll admire them from the warmth and safety of my bed.

Cover image credit: Nitulakshmi via Wikipedia