My Science School

 

It is strikingly beautiful, but extremely elusive and shy, appearing only when night falls. The snow leopard has every reason to hide. Like all animals that have warm, attractive coats, it has been hunted down to supply the fashion industry.

The snow leopard’s coat insulates it from the cold and allows the animal to blend in with its surroundings. The coat is a dappled cream or grey in colour and marked with dark rosettes arranged in distinct rows. The fur is incredibly thick, soft and luxurious.

Its tail is remarkable – it is nearly as long as its body! The leopard wraps its tail around its face like a stole when it is sleeping. It also uses the tail to balance itself when it leaps from great heights, and waves its tip like a lure to attract small animals like marmots and hares. Unlike other leopards, it cannot roar.

Snow leopards live in the Himalayas just below the permanent snow line and are found in 12 countries including India (in Ladakh). Their habitat is so forbidding that any specific research into their behaviour in the wild has been minimal.

 

Picture Credit : Google

If you are on the Australian island of Tasmania, chances are that you will run into the Tasmanian devil. It is the largest meat-eating marsupial in the world.

The Tasmanian devil earned its reputation (and nickname) because it emits spine-chilling screeches, growls and screams when defending itself or its young from a predator, when hunting, or when fighting over a meal.

It comes out at night to prey on small animals like birds, snakes, fish, insects, and it also feeds on carrion. Devils will eat everything. They have powerful bone-crushing jaws that can deliver one of the strongest bites known.

The female gives birth to nearly 30 babies at a time – aptly called ‘imps’. They are as small as raisins and must crawl through her hair to climb into the backward facing pouch. There are only four nipples in the pouch, so only that many babies survive.

 

Picture Credit : Google

The aye-aye in the largest nocturnal primate in the world. Aye-ayes are elusive and rare creatures found in only in the tropical rainforests of Madagascar, an island off the coast of Africa.

The aye-aye is rather strange-looking, with huge amber eyes, saucer-shaped ears, sharp rodent-like teeth, a dark brown or black coat, and a bushy tail that a longer than its body. Its strangest physical feature is its middle finger. All its fingers are long and slender, tipped with pointed claws, but the middle finger is extra-long and thin. It also has claws on its toes except on its opposable big toe (similar to the opposable thumb in human beings) that helps it to hang from trees.

The aye-aye lives in trees, sleeping through the day in a ball like nest of leaves and branches. At nightfall, it emerges to hunt for food, it eats mainly insects which it finds by tapping the trunk of the tree patiently with its middle finger, it is the only primate to sue echolocation to find its food. It knocks on the wood and then cocks its head to listen for the sound of beetle larvae moving around inside the bark. It nibbles away till a small hole is formed, and using its middle finger as a hook, it draws out the insects!

Loss of its forest habitat, besides superstition, is one of the reasons for its dwindling population. The people of Madagascar look at the aye-aye with superstitions dread because of its strange looks. They believe that its appearance foretells death and the animals are often killed on sight.

 

Picture Credit : Google

You have heard of sniffer dogs. Dogs are routinely used for catching thieves who have escaped. They are called in when the customs officials want to know if a package has narcotics or bombs. Some studies claim that dogs can sniff deadly diseases in their owners. But for all these dogs are trained.

Dogs have a great sense of smell and can detect tiny amounts of smell diluted in air, water, or far beneath the ground. According to the My Water Earth, the canine olfactory system works so well that dogs can pick up scents that are diluted to 1 or 2 parts per trillion; This allows them to smell things buried as far as 40 feet underground!

Dogs will take deeper, longer breaths for breathing, and use a short sniffing action when smelling something. When a dog exhales, air is pushed out of slits in the sides of the nose, creating an airflow that draws new smells into the nose.

 

Picture Credit : Google

Snakes have a highly developed sense of smell, but they don’t use their noses to smell. Instead, they “taste the air” with their tongues. They use the damp surface of their tongue to catch scent particles and carry them to a special organ in the mouth called Jacobson’s organ, where they can be identified as food or danger. But X-ray movies have revealed that the tongue does not move inside the closed mouth, it simply deposits the chemicals it has collected onto pads on the floor of the mouth as the mouth is closing.

It is most likely that these pads deliver the sampled molecules to the entrance of the Jacobson’s Organ when the floor of the mouth is elevated to come into contact with the roof following a tongue flick. The case for this is strengthened because geckos, skinks, and other lizards lack deeply-forked tongues but still deliver chemicals to their vomeronasal organs. Bears too have this organ.

 

Picture Credit : Google

Cats have twice as many receptors in the olfactory epithelium (i.e. smell-sensitive cells in their noses) as people do. That means cats have a more acute sense of smell than humans. In fact cats have 200 million odour-sensitive cells in their noses whereas humans only have 5 million odour-sensitive cells. A cat can smell stinky cat food which is several miles away, but would be less able to distinguish various types of odours. But a cat doesn’t care as long as it is able to smell its favourite food items!

Because their sense of smell is so sensitive, it’s important to be aware of things like scented litter, other animal’s smells on you or an unfamiliar scent in your cat’s environment (such as a new piece of furniture or a house guest). These things may upset your feline friend.

 

Picture Credit : Google

Kiwis are flightless birds. They forage for food on the ground. Kiwis have external nostrils which are placed at the tip of their break. This makes the search for the food beneath the soil or the fallen leaves easier. Kiwis have the second most significant olfactory bulb in all birds.

In fact, the research suggests that feeling the prey’s vibrations may be more important to a hungry kiwi than smelling it. Instead, smell may be mainly used to explore their environment.

The finding surprised researchers. Other probe-feeding birds, such as godwits and sandpipers, also have remarkably sensitive bill-tip organs to pick up prey vibrations, but these shorebirds are only very distant relatives of kiwi. It may be an evolutionary example of two distantly related animals independently coming up with the same solution to the same problem.

 

Picture Credit : Google

Among sharks, the great white species has the best olfactory bulb. The shark’s sense of smell is controlled largely by the shark’s brain. A shark can smell a drop of blood a mile away. It then cruises at top towards it. Sharks have their nostrils below the snout.

Sharks actually have roughly the same sensitivity as other fish and can detect smells at between one part per 25 million and one part per 10 billion, depending on the chemical, and the species of shark. At the top end, that’s about one drop of blood in a small swimming pool.  Smells reach a shark through the currents, and it would take time for the scent to travel that distance to a shark’s nostrils. The motion of the ocean carries smell molecules with it, so, the more motion, the faster the smell will travel.

 

Picture Credit : Google

The African elephant has 1948 scent-detecting genes. Elephants can smell their favourite grass a mile away, and can detect water 12 miles away. An elephant’s trunk has numerous receptors, and elephants use their trunks for smelling and grasping things.

Given the size of their trunks, and how important it is to their survival, it is probably unsurprising that an elephant’s nose is not only the longest in the animal kingdom, but also the most effective.

The authors then examined genome sequences from 13 placental mammals and identified over 10,000 OR genes in total. The repertoire of OR genes found in any given species was highly unique – only three OR genes were shared and evolutionarily conserved amongst all 13 mammals.

Surprisingly, the African elephant had the most extensive olfactory repertoire, with almost 2,000 OR genes.

 

Picture Credit : Google

In the insect world, the male silk moth has the sharpest sense of smell. He is a champion smeller. The feathery antennae of moths contain scent receptors. Male silk moths can inhale and identify a single scent particle from a female more than six miles away. He shows he has detected the presence of his love by walking with a swagger, moving slightly from side to side. His powerful sense of smell has inspired scientists to try and develop an artificial brain based on the moth olfactory receptor gene. One day their findings may be used in scent-detecting robots which in turn can be used to sniff out drug smuggling and chemical weapons.

Moths’ sense of smell drives most of their behaviors. Male moths find females through pheromones, and females locate the ideal place to lay their eggs by following plant odors. “What moths do,” Vickers says, “is predicated on odors.”

 

Picture Credit : Google

Of all animals on Earth, bears are supposed to have the sharpest sense of smell. A bear’s sense of smell is 2100 times better than that of a human. [Imagine a bear passing by a garbage dump! Poor thing!] Surprisingly, the bear’s brain size is one third of that of a human. But the area that controls the sense of smell is 5 times larger. Bears use this keen sense to find food and mates, to avoid enemies and keep track of cubs. Naturalists say that a bear can smell an animal carcass 20 miles away. Polar bears can detect the scent of a potential mate 100 miles away. Well, that may be because the air is clean in the polar regions!

Bears also have highly developed noses that contain hundred of tiny muscles and let them manipulate them with the same dexterity as people’s fingers. The surface area inside their 9 inch noses also has hundreds of times more surface area and receptors than a human’s.

 

Picture Credit : Google