My Science School

Emus live only in Australia, where they are widespread. Subspecies once existed on Tasmania and King Island, but they are now extinct. Emus live in eucalyptus forest, woodland, heath land, desert shrub lands and sand plains. It is found in desert areas only after heavy rains have caused growth of herbs and grasses and heavy fruiting of shrubs. Emus also live close to Australia's big cities, but are no longer found where native vegetation has been cleared for agricultural land.

Emu migrations may be a result of human agriculture. The establishment of artificial but permanent watering points in the Australian inland, where cattle and sheep graze, has enabled emus to expand into places from which they were previously excluded by lack of water. In some areas, they are now considered pests.

In arid Australia, emus will travel hundreds of miles to find another source of food or water. They must have daily access to fresh water. When food is abundant, an emu stores large amounts of fat, and is able to use this while looking for more food. Birds may lose up to 50 percent of their weight while searching for food. Emus pattern their movements to track with recent rainfall. They appear to depend mainly on the sight of rain-bearing clouds but sound cues from thunder and the smell of wet ground may also be involved.

Emus eat the parts of plants that have the most concentrated nutrients: seeds, fruits, flowers and young shoots. They also eat insects and small vertebrates when they are easily available. They will not eat dry grasses or mature leaves. Emus ingest large pebbles up to 1.6 ounces (45 grams) to help their gizzards grind up food. They also often eat charcoal.

At the Smithsonian's National Zoo, the emu is fed ratite pellets and occasionally greens such as kale and romaine.

Credit : National Zoo

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The Formosan rock macaque, also known as the Taiwan macaque, is native to the temperate forests in the mountains of Taiwan. They are the only non-human primates native to Taiwan. The species also exists in parts of Japan due to a series of both deliberate and accidental introductions that occurred in the mid-20th century.

Formosan rock macaques sport a brown coat of fur in the summer and a gray coat in the winter. They have white or gray fur covering their chests. Their faces are naked and pink with large eyes and a long, flat nose. The macaque’s jaw is built for a diverse diet, featuring four large canine teeth and several strong molars.

Formosan rock macaques are one of the 45 species of monkeys found in the subfamily Cercopithecinae. This group, consisting of macaques, baboons, and vervets, can be characterized by their cheek pouches. Monkeys with cheek pouches can quickly take large amounts of food, store them in their cheeks, and retreat to a safe place to eat without having to worry about predators or thieves. Although this adaptation did not come about with humans in mind, cheek pouches are particularly useful when hurriedly raiding human houses or trying to get as much food as possible from a tourist.

These macaques have an incredibly varied diet. Fruits make up about half of their diet. Seeds, leaves, and insects also make up significant parts of their diet. Formosan rock macaques forage from up to 300 different plants. They have also been known to raid farms and houses for foods such as sweet potatoes and peanuts.

Credit : New England Primate Conservancy

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Grey crowned crane is one of the 15 crane species found in eastern and southern Africa. It has a grey body, white wings with brown and golden feathers, white cheeks, and bright red gular sacs underneath its chin. A spray of stiff golden feathers forms a crown around its heads.

Its diet includes eating plants, seeds, grain, insects, frogs, worms and snakes. It is known for its courtship display which involves dancing, bowing, and jumping. It does not have set migration pattern. Birds nearer the tropics are typically sedentary.

It occurs in dry savannah in Africa south of the Sahara, although it nests in somewhat wetter habitats. They can also be found in marshes, cultivated lands and grassy flatlands near rivers and lakes in Uganda and Kenya and as far south as South Africa. This animal does not have set migration patterns, and birds nearer the tropics are typically sedentary. Birds in more arid areas, particularly Namibia, make localised seasonal movements during drier periods.

The grey crowned crane has a breeding display involving dancing, bowing, and jumping. It has a booming call which involves inflation of the red gular sac. It also makes a honking sound quite different from the trumpeting of other crane species. Both sexes dance, and immature birds join the adults. Dancing is an integral part of courtship, but also may be done at any time of the year.

Flocks of 30-150 birds are not uncommon.

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Golden lion tamarin is a species of monkey, found in the rainforests of the Atlantic coast of Brazil. Its body is covered with golden colour fur. Its face is dark and hairless.

It is an omnivore. It eats fruits, flowers, eggs, insects, amphibians, reptiles and birds. The young are usually twins and males often carry their young on their backs.

It is a territorial animal and defends its area with scent markings. Signs of aggression include an open mouth, an arched back, and staring.

Golden lion tamarins are omnivores. They feed upon insects, spiders, snails, amphibians, nectar, small lizards, gum, birds and their eggs and fruit.

They forage for insects within leaf litter, logs, bark and a range of plants using their elongated hands and fingers. They prefer areas with plants which attract insects to help with this.  When fruit is in abundance this forms much of their diet. When it is dry, the fruit is not readily available and they supplement their diet with other foods.

Sharing food acts as a method of reinforcing bonds between golden lion tamarins.

Picture Credit : Google

A species of horned dung beetle called Onthophagus taurus is the strongest insect on Earth with its capacity to pull over 1140 times its body weight. According to scientists, it evolved such strength as this is the deciding factor in males’ competition over females.

The beetles aren't the dung-ball-carrying variety, and instead the females bury most of the fecal material (with a little help from males) from, say, cow droppings.

The females build little tunnels where they use the dung to lay their eggs in. It's in this tunnel where mating, and the pre-mating fights between waiting males, takes place. But not all males are equipped for battle, with some sporting horns and others hornless. The no-horn beetles instead wait at the tunnel's entrance, sometimes hiding out in self-built side tunnels, and sneak in to mate before getting caught by a horned male.

The horned males, on the other hand, duke it out head-to-head.

Credit : Live Science

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When it comes to seahorses, it is the male that gets pregnant and gives birth to baby seahorses. The female swims to the surface of the water with the interested male in tow. It transfers its orange eggs into the pouch of the male which then adds its sperm and seals the opening. The growing babies will remain in their dad's pouch till they develop. Once they are born the babies are on their own.

After completing an elaborate courtship dance that may go on for hours or days, the female seahorse transfers her mature eggs into the male’s brood pouch, where they are fertilized. At the end of a gestation period usually lasting from two to four weeks, the pregnant male’s abdominal area begins to undulate rhythmically, and strong muscular contractions eject from a few dozen to as many as 1,000 fully formed baby seahorses into the surrounding water. After that, the offspring must fend for themselves. Large litters are necessary because only about 0.5 percent will survive to adulthood.

Many, if not all, of the 47 known seahorse species—14 of which were identified only in the 21st century—are in decline worldwide.

Because seahorses generally live in shallow, near-coastal waters, human activities including development, pollution, fisheries, and traditional medicine have reduced their numbers. At the same time, their universal appeal has worked against them; until recently, wild seahorses were often captured for the aquarium trade. The delicate creatures tend to fare poorly in aquaria, however. In recent years, captive-bred seahorses have shown promise as hardier tank-dwellers than their wild relatives.

Credit : National Ocean Service

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There's this fast-swimming zooplankton (a small organism) that lives in groups. And it is tiny, growing to about 6 cm. But lying at the base of the food web in the Southern Ocean, the krill is what links the ecosystem together. Its population is on the decline, and this can have an unimaginable impact on marine life in the long run. How?

A new study published recently says krill population in its Antarctic habitat is likely to decline about 30% this century due to both natural climate variability and human activity-induced climate change. The study also adds that it will be difficult to "tell the difference between natural and human-caused effects on krill until late in the 21st century". This is worrisome due to two reasons. One is that unless we know how exactly human activity affects krill population, it may be difficult to initiate relevant steps to improve the situation. Two, it is said that "natural climate variability can obscure human-driven trends". Neither augurs well for the krill population.

As mentioned, krill are tiny creatures. But they are one of the most abundant too. For several sea creatures including penguins, seals, fish, and whales - in the ocean surrounding Antarctica, krill are the main food. Not just that. Many sea animals feed on the creatures that consume krill, which is why the krill has an important role to play in the aquatic food chain, especially in the Southern Ocean. If the krill population keeps coming down, it could affect several other creatures, causing a severe imbalance in the food chain. Krill are adapted to surviving harsh winters. But one wonders how well they can adapt to climate change.

Did you know?

The largest animal on Earth, the blue whale feeds almost exclusively on krill. Apparently, it needs to eat a few tonnes of these tiny crustaceans every day!

Picture Credit : Google

Previously in this column, we learnt about how forests act as carbon sinks. We know that trees absorb carbon from the atmosphere through photosynthesis. The gas then becomes deposited in tree biomass and in soil. But what happens when trees die? Do they release the stored carbon? Yes, they do. But how much? This is something scientists have not measured until recently. A series of new experiments, published in the journal Nature this month, is the first to put a number to this carbon emission. The study carried out by researchers from the Australian National University also draws our attention to the potential role of climate change and insect population in influencing this carbon cycle.

When trees die

When a tree dies, a new life springs forward. Fungi communities flourish on dead wood and small organisms such as salamander and insects create breeding grounds. Logs (dead trees on the ground) and snags (standing dead trees) provide a place to nest, rest, eat and grow for a number of organisms. The trees eventually decompose over a period of time. The speed at which deadwood breaks down depends mainly on interactions between the local climate and the activity of decomposers, such as fungi, microorganisms, and insects. When this decomposition happens, the trees release carbon dioxide, among other gases. The movement of carbon and other gases within forests and soils, thus, occurs in cycles. However, the full picture of the role decomposing wood plays in the global carbon cycle had been difficult to estimate.

Measuring the emission

To estimate how much carbon decaying and dead trees emit and to determine the influence of climate on the rate of decomposition, scientists from the Australian National University studied wood from more than 140 tree species in 55 forest areas on six continents. They conclude that deadwood, which includes fallen trees, standing dead trees, trunks and fallen branches, contain roughly 8% of all the carbon on Earth. Each year, on average, about 10.9 gigatons of carbon are released from decaying woody matter around the world. That's equivalent to 115% of global annual fossil fuel emissions. Of course, not all the carbon released from deadwood goes into the atmosphere. Some becomes trapped in the soil or in creatures that use the wood for food or shelter.

Role of climate change & insects

During the study, the researchers found out that in regions where the temperature and humidity is high, the deadwood weathered and decomposed much faster. They also noticed the role played by the abundance of decomposing insects in these regions. In cooler temperate climes, the opposite happened. The boreal and temperate forests account for less than 7% of carbon released from deadwood each year.

This suggests that climate change might increase wood decomposition in tropical or subtropical areas as temperatures rise.

In recent years, scientists have begun to notice an 'insect apocalypse' occurring around the world, including in the tropics where most insect diversity resides. This dramatic loss of decomposers will have a massive impact on deadwood and its carbon emission. Thus both climate change and the loss of insects have the potential to alter the decomposition of wood, and therefore, carbon and nutrient cycles worldwide.

Picture Credit : Google

Tardigrade is a microscopic animal found everywhere on Earth – from the deep sea in the mud volcanoes. There are around 1300 species of tardigrades. We are also called water bears or moss piglets.

It has eight limbs with four to eight claws on each. Its body is covered in a tough cuticle, similar to the exoskeletons. It is known for being the most resilient animal, because it can survive extreme conditions such as exposure to extreme temperatures, extreme pressures, radiation and starvation. It can go up to 30 years without food and water.

In extreme dry conditions, it gets into a death-like state called cryptobiosis. It squeezes all the water out of its body, retract its heads and limbs and curl up into a little ball. When conditions improve, it unfurls itself and goes about its business. It sucks the juices from algae, lichens and moss using its tube-shaped mouth.

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Hedgehog is a spiny mammal that belongs to the family Erinaceidae, found in Europe, Asia and Africa. It has an elongated snout and body covered with 5000 to 6500 non-poisonous quills. It replaces the old quills with new ones each yea.

If attached it curls into a prickly and unapestising ball that deters most predators. It feeds on insects, worms, centipedes, snails, mice, frogs and snakes. It hibernates in cold climates.

The body of adult hedgehogs ranges from 14 to 30 centimetres long, and their tail can add one to six centimetres. When they are born (there can be up to seven in a litter) their spines are soft and short. But soon after birth, their spines harden, becoming stiffer, sharper and longer. Babies stay in the nest until they”re about three weeks old. By that time, their eyes are open, their spines are effective and they can safely follow their mother outside the nest as she looks for food.

Top on the hedgehog”s menu are insects, followed by small mice, snails, lizards, frogs, eggs and even snakes. Mostly nocturnal creatures, they head out at night in search of food – but they are sometimes active during the day, too, particularly after it rains.

Credit : National Geographic

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Yes, they do, says research. Since turtles don't have vocal cords, it was thought that they did not communicate through sounds. However, scientists have found that turtles communicate at such low frequency that sounds like "clicks, clucks and hoots" can be heard only through a hydrophone. What's surprising is that they talk when they are still inside their eggs just before hatching.

One of the most common sounds which a turtle may produce is the hissing sound. Turtles hiss by quickly expelling air from their lungs. They do this by tucking their heads into their shells.

A turtle in a new environment will hiss a lot as it is not used to its environment. Once the turtle gets used to its environment, you can expect it to hiss less. Snappers) hiss when approached.

They do this because they are stressed and feel threatened. Hissing coupled with heavy breathing produces a menacing sound. A threatened snapping turtle will attack when approached or provoked. Their bites are very powerful and are capable of crushing human bones.

When a turtle hisses, it’s best to leave it alone.

Credit : All Turtles

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Heard of Jonathan, the Seychelles giant tortoise? Aged 188, he is the oldest living land animal in the world. Said to have hatched in 1832, he lives on the island of St. Helena, a British Overseas Territory in the South Atlantic Ocean.

His age is estimated because he was 'fully mature' when brought to Saint Helena in 1882. 'Fully mature' means at least 50 years old, giving him a hatching date no later than 1832. A photograph featuring Jonathan originally thought to date from 1902 actually dates from 1886, showing Jonathan four years after his arrival on Saint Helena. Measurements taken from the photograph show that he was definitely fully mature in 1886.

The all-time verified record holder for the world's oldest tortoise, according to Guinness World Records, is Tu'i Malila, which died in Tonga in 1966 at the age of 189. Adwaita, an Aldabra giant tortoise that died in 2006 in the Alipore Zoological Gardens of Kolkata, India, is believed to have lived to the age of 255 years, but this has not been confirmed.

As of December 2015, Jonathan was reported to be "alive and well [...] He's blind from cataracts, has lost his sense of smell, and so cannot detect food (his fellow giants mug me and can detect the tiniest morsel dropped on the ground), but he has retained excellent hearing." In January 2016, the BBC reported that Jonathan was given a new diet intended to keep him healthy and extend his life. Due to his old age, Jonathan spends his days doing almost everything with his mate, including eating, sleeping, and mating.

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The snood is similar to a wattle, and may be called a wattle when all of a turkey's face, head, and neck markings are described together, but it is a distinct feature. The base of the snood is just above the bill, and the total length can vary from just 1-2 inches to 5-6 inches or longer depending on the bird's gender, health, and mood. A short snood may stand upright and be pointed like a small horn, while a longer snood will dangle down the bird's bill and may flop on one side or the other.

A snood is a fleshy protuberance above a male turkey's bill that can, in some cases, hang down and cover the bill. It can vary dramatically in size, shape, and color. Snoods function in sexual selection: Female turkeys choose who to mate with based on a variety of factors including snood size.

Because the snood is fleshy and blood-filled, it can change length quickly. A short, compact snood may indicate an agitated bird, and turkey hunters have noted the snood shortening and withdrawing when a bird feels trapped or threatened. This may be a defensive response, since a long, dangling snood can be a hazard in a fight: if the snood is injured, the bird may bleed profusely, and the snood could easily become infected through an open wound. Because turkeys can be aggressive, farmers who raise turkeys may have their birds de-snooded as chicks, removing the protuberance and lessening the risk of injury or infection.

Credit : The Spruce

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If you thought humans alone are capable of blushing, think again. When turkeys are scared, annoyed or excited, the pale pink-coloured skin on their head and neck turns into a vibrant red, blue or white. The skin hanging from the top of the turkey's beak too turns red.

Male turkeys have 18 tail feathers that make up their impressive fan, which they will open and spread out during mating season.If the feathers in the tail fan aren’t all the same length, you can tell this is an immature male. Their eyes are on the sides of their heads, giving them periscopic vision that is super useful in seeing predators. They are thought to see about 3 times better than humans. They can see an amazing 270 degree field of view.They do however, have poor night vision.

Female turkeys build their nests on the ground, covering their 12-18 spotted eggs with leaves when they are off in search of food.  Females hide their nest locations from the males and do all of the work by themselves in raising the chicks. For the first two weeks, the chicks, or poults as they are called, cannot fly, so mom will roost on the ground with them during this time. The poults will stay with their mothers for a year. (In the photo with the trees there is a turkey nest at the base of the right-most tree). They are omnivores, feeding on a variety of foods including seeds, acorns, berries, nuts and insects like crickets and grasshoppers. If you ever get a chance to watch a flock in a field, you can see them snagging insects in the grass as a child would grab at pieces of candy.

Credit Nature for my soul

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Parrotfish are bright-coloured fish found in and around coral reefs. They have fused teeth resembling a parrot beak which they use to scrape algae and seaweeds from the surface of corals and rocks, thereby helping the reefs stay healthy. They grind up the calcium carbonate reef material and excrete it as fine white sand.

Parrot fishes range to a length of about 1.2 metres (4 feet) and weight of about 20 kilograms (45 pounds), or occasionally larger. They are variable in colour, the male of a species often differing considerably from the female, and the young may differ from the adult. Parrot fishes are protogynous hermaphrodites; that is, they first function as females and later transform into males.

Parrot fishes are edible but are not, as a group, of great economic importance. The surf, or rivulated, parrot fish (Callyodon fasciatus) is an Indo-Pacific representative of the family; it grows to 46 centimetres (18 inches) or more, and the male is green and orange or red, the female blue and yellow. Atlantic species include the rainbow parrot fish, which grows to about 90 centimetres and is bright orange and green with a blue beak, and the queen parrot fish (Scarus vetula), which grows to about 50 centimetres and is blue with green, red, and orange if male but reddish or purplish with a white stripe if female.

Credit : Britannica

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