My Science School

Spectacled bear is the only species of bear that lives in South America. It inhabits the dense Andean jungles. Its body is covered in brown, black or reddish fur. Patches of creamy fur can be seen on the chest, throat and around the eyes. The whitish markings around the eyes look like spectacles and that’s how it got its name. However, some individuals lack the patches.

It spends most of its time on the trees, descending only to search for food. It is a solitary animal. Mature spectacled bears are normally seen together only during mating season.

It feeds mainly on shoots and fruit, but occasionally supplements its diet with meat. It does not hibernate.

Their habitat is being destroyed by a number of things such as farming, lumber and mining operations. They also sometimes are hunted by farmers because as their habitat shrinks they may stray onto farmland and eat the crops that have replaced their natural diet. Also some farmers think that the bears will eat their livestock although they do not eat large quantities of meat. They are hunted for their gall bladders which can fetch a high price in the international market as they are valued in traditional Chinese medicine.

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Manatees constantly grow molars, but are incapable of biting anyone. These gentle marine mammals eat seagrass many hours a day. The sand granules eaten along with the grass wear down their teeth which eventually fall off. As the front teeth fall off the molars at the back get pushed forward, which is why they are called "marching molars."

Manatees were once thought to be mermaids by early sailors, including Christopher Columbus, who described the “mermaids” as less beautiful than he imagined with masculine faces. In fact, manatees belong to the order Sirenia, which derives its name from the sirens (or mermaids) of Greek mythology. A common myth regarding manatees is they are an invasive species in Florida imported to control exotic aquatic plants. Florida manatees are in fact native to the United States, as seen in both the fossil records and in Native American sites. Depending on the time of year they can be frequently found in Florida, Alabama, and Georgia. On very rare occasions Florida manatees have been seen as far north as Massachusetts!

Manatees use their tails in an up and down motion to propel themselves forward. Strong swimmers, they are capable of reaching speeds of 15 miles per hour in short bursts. Manatees rest from 2 to 12 hours a day either suspended near the water's surface or lying on the bottom, usually for several hours at a time.

While most people tend to see many manatees gathered together at winter warm-water sites, during the rest of the year these animals are semi-social as they travel around the state’s waterways in search of food, mates or places to rest. Except for cow/calf pairs and small mating herds, manatees do not need to travel together although they do socialize when other manatees are encountered.

Manatees reach sexual maturity in 3-5 years (females) and 5-7 years (males) and may live over 65 years in captivity. Gestation is approximately 13 months and usually one calf is born. The calf may stay with its mother (cow) for up to 2 years. Male manatees (bulls) are not part of the family unit. Bulls will leave a cow alone after her breeding period is over. Of the wild manatees that reach adulthood, only about half are expected to survive into their early 20s.

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The Komodo dragon is the world's largest living lizard. Growing up to 3 metre long and weighing over 70 kg, the species is found on Komodo Island, one of the many islands that comprise Indonesia.

Komodo dragons are limited to a few Indonesian islands of the Lesser Sunda group, including Rintja, Padar and Flores, and of course the island of Komodo, the largest at 22 miles (35 kilometers) long. They have not been seen on the island of Padar since the 1970s.

They live in tropical savanna forests but range widely over the islands, from beach to ridge top.

Komodo dragons eat almost any kind of meat, scavenging for carcasses or stalking animals that range in size from small rodents to large water buffalo. Young feed primarily on small lizards and insects, as well as snakes and birds. If they live to be 5 years old, they move onto larger prey, such as rodents, monkeys, goats, wild boars and deer (the most popular meal). These reptiles are tertiary predators at the top of their food chain and are also cannibalistic.

Although the Komodo dragon can briefly reach speeds of 10 to 13 mph (16 to 20 kph), its hunting strategy is based on stealth and power. It can spend hours in one spot along a game trail — waiting for a deer or other sizable and nutritious prey to cross its path — before launching an attack.

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Yes, the common housefly can taste food with its feet though it uses its mouth to eat. This is because its taste receptors that facilitate the sense of taste are located in its lower legs and feet. So when it lands on anything edible, it reflexively extends its proboscis or mouthpart to consume it. It is said that their feet are 10 million times more sensitive than our tongues.

The need for so many taste organs in insects is not understood very well. However, a clue for understanding their function comes from examining the anatomy of the taste-sensing neurons. These neurons send projections to different parts of the central nervous system of the fly. This suggests that taste information received from different parts of the body is processed differently in the brain. Therefore, different taste organs may have different functions.

To test this idea, Thoma et al. used the fruit fly Drosophila as a model for insects. With Drosophila, it is possible to target small numbers of neurons and to block them or activate them with genetic tools. The scientists blocked different groups of sweet-sensing neurons and measured sugar choice, the first step in feeding behavior. Normally, hungry flies choose sugar very quickly, but the flies which had all sweet-sensing neurons in their legs blocked could not choose sugar.

The scientists then examined the sweet taste neurons in the legs and found two populations of neurons. One group of neurons connected directly to the brain of the fly. The remaining neurons connected to the ventral nerve cord, a structure analogous to the spinal cord in humans.

Credit : ScienceDaily

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Parasaurolophus is a hadrosaurid (sometimes referred to as the hadrosaurs or duck-billed dinosaurs) from approximately 76.5–73 million years ago (late Cretaceous). It is a herd animal feeding on the park’s rich vegetation. The most stunning feature of the Parasaurolophus is the crest on its head

Parasaurolophus was a hadrosaurid, part of a diverse family of Cretaceous dinosaurs known for their range of bizarre head adornments. This genus is known for its large, elaborate cranial crest, which at its largest forms a long curved tube projecting upwards and back from the skull. Charonosaurus from China, which may have been its closest relative, had a similar skull and potentially a similar crest. Visual recognition of both species and sex, acoustic resonance, and thermoregulation have been proposed as functional explanations for the crest. It is one of the rarer hadrosaurids, known from only a handful of good specimens.

The most noticeable feature was the cranial crest, which protruded from the rear of the head and was made up of the premaxilla and nasal bones. The crest was hollow, with distinct tubes leading from each nostril to the end of the crest before reversing direction and heading back down the crest and into the skull. The tubes were simplest in P. walkeri, and more complex in P. tubicen, where some tubes were blind and others met and separated. While P. walkeri and P. tubicen had long crests with only slight curvature, P. cyrtocristatus had a short crest with a more circular profile.

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Stegosaurus was a plated dinosaur that lived in North America during the Late Jurassic Period. It had a bulky body with a high, arched back and pillar-like limbs.

The skull and brain of Stegosaurus were especially small for such a large animal. Its narrow head measured only 16 inches (40 centimeters) long. There once was a mistaken belief that this dinosaur had two brains because the sacrum region of the spinal cord was actually larger than its brain cavity. Recent theories suggest, however, that the sacrum region may have been used to store glycogen, which contains carbohydrates, as it does in several modern animals.

The most striking feature of Stegosaurus was the enormous triangular-shaped line of plates along its spine. Each horn-covered, bony plate stood more than 2 feet (60 centimeters) tall. Each individual plate of every dinosaur had its own distinctive size and shape; no two were alike. There has been much debate among paleontologists as to the function of these plates. The alternating positions of the structures, which also contained several blood vessels, have led some paleontologists to believe that they were used for thermoregulation—that is, to help the dinosaur control its body temperature. They could either act as solar panels to soak up the warmth of the sun, or they could help the animal to release excess body heat into the atmosphere. Other paleontologists believe that Stegosaurus used its plates for species recognition and for display purposes during the breeding season. One very likely function of these plates was to provide Stegosaurus with protection from predators such as Allosaurus. This unique feature inspired the name Stegosaurus, which means “covered lizard,” or “roof lizard.”

Credit : Britannica

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Archaeopteryx lived around 150 million years ago — during the early Tithonian stage in the late Jurassic Period — in what is now Bavaria, southern Germany. At the time, Europe was an archipelago and was much closer to the equator than it is today, with latitude similar to Florida, providing this basal bird, or "stem-bird," with a fairly warm — though likely dry — climate.

Various specimens of Archaeopteryx showed that it had flight and tail feathers, and the well-preserved "Berlin Specimen" showed the animal also had body plumage that included well-developed "trouser" feathers on the legs. Its body plumage was down-like and fluffy like those of the feathered theropod Sinosauropteryx, and may have even been "hair-like proto-feathers" that resemble the fur on mammals, according to a 2004 article in the journal Comptes Rendus Palevol.

Interestingly, the Archaeopteryx specimens found thus far lack any feathering on the upper neck and head, which may be a result of the preservation process.

Based on its wings and feathers, scientists believe Archaeopteryx likely had some aerodynamic abilities.

A 2018 study published in the journal Nature Communications also found evidence that Archaeopteryx could fly, although not like any bird alive today does. The researchers used synchrotron microtomography — a tool that uses radiation to make magnified, 3D digital reconstructions of an object — to study the Jurassic creature's fossils. Even though Archaeopteryx didn't have the same features in its shoulders that help modern birds fly, its wings looked like those of modern birds that fly, they found.

Credit : Live Science

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Velociraptor retained its feathers, and possibly used them to attract mates, regulate body temperature, protect eggs from the environment or generate thrust and speed while running up inclines.

Velociraptor had a relatively large skull , which was about 9.1 inches (23 centimeters) long, concave on the upper surface and convex on the lower surface, according to a 1999 description of a Velociraptor skull, published in the journal Acta Palaeontologica Polonica. Additionally, its snout was long, narrow and shallow, and made up about 60 percent of the dinosaur's entire skull length.

Velociraptor had 13 to 15 teeth in its upper jaw and 14 to 15 teeth in its lower jaw. These teeth were widely spaced and serrated, though more strongly on the back edge than the front.

Velociraptor's tail of hard, fused bones was inflexible, but likely kept it balanced as it ran, hunted and jumped. 

Velociraptor, like other dromaeosaurids, had two large hand-like appendages with three curved claws. They also had a sickle-shaped talon on the second toe of each foot. 

Credit : Live Science

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Bone-headed dinosaurs, or thick-headed lizards, are known scientifically as pachycephalosaurs.

They are a strange group of herbivorous dinosaurs which possessed a thick-boned dome on the top of their skulls.

The unusual and distinctive feature of Pachycephalosaurusis the high, domelike skull formed by a thick mass of solid bone grown over the tiny brain. This bone growth covered the temporal openings that were characteristic of the skulls of related forms. Abundant bony knobs in front and at the sides of the skull further added to the unusual appearance. Pachycephalosaurusand closely related forms are known as the bone-headed, or dome-headed, dinosaurs. These dinosaurs, which are also found in Mongolia, had a variety of skull shapes. In the most basal forms, the dome was not thick but flat. Late forms had thick domes shaped like kneecaps, or a large sagittal crest with spikes and knobs pointing down and back from the sides of the skull. It has been suggested that these animals were head butters like living rams, but the configuration of the domes does not support this hypothesis. Flank-butting remains a possibility in some species, but a more likely function in most was species recognition or display.

Credit : Britannica

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Opossum is a marsupial endemic to the Americas. It loves to visit human homes and raid garbage for food. Its favourites are nuts and fruits, but it also love to hunt mice, birds and insects.

To escape its predators, it plays possum. That is, it pretends to be dead in appearance and in smell. It carries its babies in its pouch or on its back when it goes looking for food.

An opossum, when confronted with a threat, will often hiss or bare its teeth. Or more likely, run. But if it is surprised by a predator, it will enter a catatonic state. It basically faints and is in a state of unconsciousness. The opossum has no control over this; it’s involuntary.

It does indeed appear if the opossum is dead. Its teeth are visible, as if in a death grimace. It emits a foul substance from its anus, the smell described as corpse-like.

A predator is confronted with what appears to be dead, unhealthy prey, and may leave the opossum alone.

This death-feigning strategy, as some sources note, is not without its risks. The opossum is unconscious. So if the predator decides to gnaw on the opossum anyway, there’s no escape. It is also commonly cited as a reason why you see so many road-killed opossums, but I found a lack of research support for this.

The opossum will remain in this unconscious state for minutes to hours.

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Tardigrade is a phylum, a high-level scientific category of animal. (Humans belong in the Chordate phylum — animals with spinal cords.) There are over 1,000 known species within Tardigrade, according to Integrated Taxonomic Information System (ITIS).

In many conditions, they survive by going into an almost death-like state called cryptobiosis. They curl into a dehydrated ball, called a tun, by retracting their head and legs. If reintroduced to water, the tardigrade can come back to life in just a few hours.  

While in cryptobiosis, tardigrades' metabolic activity gets as low as 0.01 percent of normal levels, and their organs are protected by a sugary gel called trehalose. They also seem to make a large amount of antioxidants, which may be another way to protect vital organs. Water bears also produce a protein that protects their DNA from radiation damage, according to research by the University of Tokyo.

In cold temperatures, they form into a special tun that prevents the growth of ice crystals. 

Tardigrades reproduce through sexual and asexual reproduction, depending on the species. They lay one to 30 eggs at a time. During sexual reproduction, the female will lay the eggs and the males will fertilize them. In asexual reproduction, the female will lay the eggs and then they will develop without fertilization. 

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Tardigrades, also known as water bears, are microscopic, usually about 0.5 mm long. These water-dwelling, eight-legged micro-animals can survive extreme heat and cold, besides even radiation in space. They are often found on mosses and lichen. Did you know when short on water they can dry out for years and revive without any damage when reintroduced to water?

Tardigrades are semi-aquatic. They can survive in watery as well as terrestrial environments — from oceans and lakes to mountains, forests and sand dunes. They're found all over the world, from frigid Antarctic glaciers to active lava fields. They’re most commonly found living in moss.

Most tardigrades eat algae and flowering plants, piercing plant cells and sucking out their contents though their tube-shaped mouths. Some, however, are carnivorous and may eat other tardigrades.

Tardigrades are nature’s pioneers, colonizing new, potentially harsh environments, providing food for larger creatures that follow. Scientists say, for instance, that tardigrades may have been among the first animals to leave the ocean and settle on dry land.

Tardigrades pose no threat to humans. Scientists have yet to identify a species of tardigrade that spreads disease.

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The Sphynx cat, or simply Sphynx is a breed of cat known for its lack of fur. Hairlessness in cats is a naturally occurring genetic mutation, and the Sphynx was developed through selective breeding of these animals, starting in the 1960s.

According to breed standards, the skin should have the texture of chamois leather, as it has fine hairs, or the cat may be completely hairless. Whiskers may be present, either whole or broken, or may be totally absent. The cats have a narrow, long head and webbed feet. Their skin is the color that their fur would be, and all the usual cat markings (solid, point, van, tabby, tortie, etc.) may be found on the Sphynx cat's skin. Because they have no fur they lose more body heat than coated cats which makes them warm to the touch and prone to finding warm places.

Sphynx are known for their extroverted behavior. They display a high level of energy, intelligence, curiosity and affection for their owners. They are one of the more dog-like breeds of cats, frequently greeting their owners at the door and friendly when meeting strangers.

The Sphynx breed also tends to accumulate oils and debris under the nails as well as the skin fold above the nail due to the lack of fur, so, like the ears, the nails and surrounding skin folds need to be cleaned properly as well. Due to these factors the breed may require more grooming than a typical domestic cat with fur. Specialty products for this cat have been developed, though they still require more grooming than most breeds.

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Those who cannot own a dog because of scarcity of space or some other reason could consider having a dog-like cat as a pet. Dog-like cat? Yes, some breeds of domestic cats exhibit unusual dog-like behaviour such as being loyal, friendly, playful, interactive and adventurous. What's more? They can be trained too. Manx, Ragdoll and Abyssinian are some of the cat breeds known to display canine behaviour.       

The cultural assumption that cats are distant from people and lack affection compared to dogs has complications.[3] Animals have individual characteristics based on their environment, particularly their past interactions with people. The nature of selective breeding for both canines and felines varies dramatically across different human cultures as well, with highly distinctive traits (fertility, lifespan, speed, etc) receiving emphasis depending on the historical context.

The feline temperament is particularly malleable to a wide set of environmental factors, especially sudden stresses. For example, after dangerous floods in Canvey Island, cats showed behaviors of psychological shock akin to human struggles. Well-raised kittens frequently demonstrate affection towards humans and a pleasant, docile nature regardless of pedigree. These broad traits are not specific to any particular breed, as the upbringing of the animal is an important factor. Positive interaction with humans in the first few months of life is particularly vital.

Most feline pets in the United States are considered to be domestic short-haired cats, a catch-all term for those with mixed or otherwise unclear ancestries but having related appearances. Several of those cats, or those of the standardized American Shorthair breed, will respond differently to others despite looking very similar, displaying dog-like or otherwise unexpected tendencies. Besides breed-based generalizations, a particular cat's behavior can be assessed by its restraint in using claws during play, its tendency to follow people, and its appreciation of close, frequent human contact.

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Ethology, the study of animal behaviour. Ethology is a combination of laboratory and field science, with strong ties to certain other disciplines—e.g., neuroanatomy, ecology, evolution. The ethologist is interested in the behavioral process rather than in a particular animal group and often studies one type of behaviour (e.g., aggression) in a number of unrelated animals.

 The word ethology is derived from the Greek word ethos, meaning “habit” or “character” and logos, meaning “study”. The term ethology was introduced by Niko Tinbergen (1950). Ethology is defined as the systematic and scientific study of the behaviour of animal (including human) under natural conditions.

Genetics, developmental biology, ana­tomy, physiology, endocrinology, neuro­biology, evolution, learning and social theory are all combined into one grand subject — animal behaviour. The field of ethology is, thus, integrative in the true sense of the word.

Credit : Britannica

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