My Science School

Fish breathe in water and animals breathe on land, is an age-old saying. The Arapaima fish, however, has something entirely different to say!

The Arapaima is an air-breathing fish that plies the Rainforest Rivers of South America’s Amazon Basin and nearby lakes and swamps. Acknowledged as one of the largest of all freshwater fish, these giants are fondly called by the name ‘paiche’ or ‘pirarucu’ and you will soon know why.

Though it is believed to grow up to a whopping 15 feet in length, the most common sightings measure an average length of six feet and a weight of about 91 kilogrammes!

The Arapaima has a striking appearance that cannot be mistaken for anything else. The head is tapered and has a copperish-green tint. The mouth is upturned and the streamlined body is scaly and black with a white centre. Arapaimas have an outstandingly red dorsal fin that stretches from front to back giving it the local name ‘pirarucu’ meaning ‘red fish’. The Arapaimas have to ‘gulp’ in the air every ten minutes and so inhabit the shallow depths just below the water surface. These ‘gulps’ which sound more like a cough, can be heard kilometres away!

These voracious predators are mainly fish hunters. They also eat fruits, seeds, insects, lizards, birds, and even small primates dangling on low-lying branches!

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Orang-utans are great apes indigenous to the tropical rainforests of the Sumatran and Bornean islands. Of the three species identified so far, the Bornean type flourishes across the width and breadth of the Bornean Island and the Sumatran and Tapanuli species in Northern Sumatra.

It is easy to recognize an orang-utan from other primates by its red fur coat. They resemble apes in their shape. The arms are disproportionately longer and more agile than the legs. Orang-utans can touch their ankles without bending even a bit! Can you do that?

These arboreal primates possess excellent cognitive abilities similar to gorillas and chimpanzees and are slightly smaller than the former.

Orang-utans are known as the ‘gardeners of the forest’. They play the role of stakeholders and are vital in seed dispersal and forest growth.

Arboreal in nature, they seldom come down unless absolutely necessary. They are often attacked and killed by leopards, tigers and crocodiles. However, the most significant threat arises from habitat loss due to road development, timber trade, and commercialized agricultural activities.

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The clouded leopard, named for its spotted coat, is one of the most ancient of cat species. They are closely related to great cats like the lion, and are slightly bigger than domestic cats. But despite all these similarities, the clouded leopard can hardly roar!

Clouded leopards plod the lowland rainforests that range across Nepal, Bangladesh, and eastern India and extend to Sumatra and Borneo. They have been sighted across dry woodlands and swampy terrains as well. The Bornean clouded leopards are more robust than the others. The reason behind this is the absence of tigers and other leopards in the region.

When it comes to climbing trees, clouded leopards are top-notch and often outdo other cat species. The large paws and sharp claws aid in better grip around the tree. These skilled climbers can also be seen hanging upside down from branches. Their bodies come with long tails and relatively short legs.

Despite their love for climbing trees, the clouded leopards prefer hunting on land. They feast on deer, monkeys, pigs, squirrels, birds, and even little squirrels.

Apart from these known facts, much remains to be learnt about them. They are seldom seen in the wild and are considered a vulnerable species.

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You have heard much about the Australian kangaroos that leap and bounce on land. But what about their arboreal cousins, the tree kangaroos?

The tree kangaroo shares the common physical traits of kangaroos and lemurs and inhabits the lowlands and mountainous rainforests of Indonesia, Papua New Guinea, and Australia. A total of fourteen species of tree kangaroos have been identified so far.

Their life on trees has enabled them to adapt better. The species has developed strengthened forelimbs and shorter legs to boost better and faster climbing. They weigh up to 14.5 kg and grow to a length of around 90 cm. Tree kangaroos wear a chestnut-brown coat adorned by two golden stripes on the back. Hence, the animal also goes by the name, ‘the golden-mantled tree kangaroo’.

Shreds of evidence reveal that kangaroos, wallabies, and the tree kangaroos are closely related marsupials descending from the same ancestors called macropods. Scientists believe that macropods were essentially tree-dwelling animals that existed millions of years ago.

Illegal poaching and habitat destruction have led to a massive decline in the total population of this plant-eating marsupial.

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Spiders remind us of two things: flimsy cobwebs, and little dangling legs that hang upside down on patterned threads.

The spider monkeys do the same! They can hang upside down by their tails that hold on to the branch and let their arms and legs dangle in the air!

The spider monkey is a New World monkey and dwells in the upper layers of the Central and South American rainforest canopies.

Its long and skinny limbs are disproportionate and add to its overall largeness in size. The highly dexterous prehensile (gripping) tails function as body balancers while shifting from one branch to another and aids in picking up small objects.

These tree-dwellers are social and diurnal and spend most of the day foraging on fruits, leaves, nuts, and sometimes insects and bird eggs.

The spider monkeys are sold for large amounts of money at the bushmeat market. Massive hunting, coupled with widespread logging, has deprived and driven them off from their natural habitat.

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Imagine you are trekking inside a dense forest, famished. Suddenly your nose catches the smell of buttered popcorn! Well, the chances of finding a bag of popcorn in the middle of the dense forest are extremely dim. But there can very well be a bearcat prowling somewhere right behind you!

The forest bearcat, also known as binturong, is a medium-sized, carnivore that inhabits the rainforests of Southeast Asia, especially India, Bangladesh, the Malay Peninsula, Borneo, and the Philippines.

They have prehensile tails that resemble the monkeys and their white whiskers and purring sound remind us of cats.

But what has popcorn got to do with them?

Binturongs mark their territories by leaving behind a trail of scent that smells very much like buttered popcorn!

It might sound gross, but a local coffee brewed from the beans that pass down its digestive system, also fetches good money.

Much of this animal’s characteristic behaviour has not been extensively observed. But it is known that they have a sweet tooth for fig fruits. They make good pets, thanks to their mostly gentle behaviour, unless provoked! Like most other endangered species, the Binturongs too, are under the threat of being wiped off from their natural habitat.

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The okapi is a wild animal with a serious ‘identity crisis’. Wondering why? Its face resembles that of a deer but it has striped markings that are reminiscent of a zebra. However, scientists call it neither a deer nor a zebra, but a ‘forest giraffe’. It is the only close living relative of the giraffes!

The okapis may be described in three words: endemic, diurnal and solitary. Endemic, because they are found only in the dense Ituri rainforests of the Democratic Republic of Congo; diurnal, because they are active mostly during the day; solitary, because they are always seen alone, except while breeding and playing.

The brown and white stripes found on its hind legs appear as penetrating streaks of sunlight and aids the Okapi to remain invisible from cheetahs and other predators.

Similar to that of cows and giraffes, the Okapis have four stomachs each. This facilitates the effective digestion of their highly fibrous and herbivorous diet of fruits, buds, leaves, and twigs. One can easily spot the males by their short horns. Females have knobby bumps instead.

Scientists fear that the past two years have witnessed a drastic 50 per cent decline in the total population of okapis, mainly due to natural predators and human hunting. The okapis are now categorized under ‘Endangered’, according to the IUCN Red List of Threatened Species.

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The island of Madagascar in Africa is best known for its colourful chameleons, orchids, unique flora and fauna and most importantly, its lemurs. The world’s largest nocturnal primate, the aye-aye, is one such lemur endemic to the island. Its natural habitat is rainforest but many now live in cultivated areas because of deforestation.

The aye-ayes are characterized by a distinctly long and thin middle finger and rodent-like teeth. Like the black howler monkeys, they avoid coming down from treetops and spend the daytime snuggled inside a ball-like nest made of leaves and branches.

Aye-ayes are great acoustic engineers! These avid ‘worm-eaters’ tap on tree trunks and listen carefully to the different echo patterns. This unique technique, called foraging, helps them spot the presence of wood-boring insect larvae within the empty hollows. With their middle finger, they gnaw holes into the bark and spoon out the grubs that make a happy meal.

It was Pierre Sonnerat, a French naturalist, who first used the vernacular name ‘aye-aye’ (resembling the Malagasy name ‘hay-hay’) given to this animal.

The aye-ayes are seen as evil harbingers of death by the superstitious natives of Madagascar. Ruthless slaughters of the aye-aye and deforestation practices have contributed to its decimation, giving it the ‘Endangered’ status by the IUCN.

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Have you watched Walt Disney’s animated film, Zootopia? If you have, then you might remember the annoyingly slow-moving sloth character who works at the Department of Mammal Vehicles?

Sloths are mammals known for their sluggish movements. They can either have two toes, or three, and have remarkably long claws.

Found in the rainforests of Central and South America, sloths sleep for 15 to 20 hours a day and spend most of their life hanging upside down on tree branches, thanks to their powerful claws! The grip of these claws is so powerful that even after the death of sloths; their lifeless bodies are often seen hanging on branches!

Sloths are excellent swimmers but on land, they are submissive and stand little chance against predators. Their hind legs are weak, and they move forward by dragging their bellies across the ground and digging each step using their front claws.

Apart from providing shelter, trees assure refuge and safety to sloths from predators, and supply nourishment through food - leaves, stems, and fruits. The symbiotic green algae that grows on its furry coat gives the sloth a camouflaged green appearance.

The word ‘sloth’ literally means ‘lazy’ and is synonymous with lazy people. So, next time, if anyone lovingly calls you a ‘sloth’, you need to think before you smile.

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Looks like it’s time for some serious ‘monkey talk’.

The black howler monkey is a unique herbivorous primate and is regarded as the largest among the New World monkeys (monkeys that are indigenous to the rainforests of the Americas). They are found to inhabit the tropical areas of Bolivia, Paraguay, and Argentina.

The black howler monkeys are known by that name because of two obvious reasons which are their black fur coat and their distinct howl. Males wear a black fur coat, while females parade a blonde one.

The howling of these monkeys is strong enough to penetrate the dense terrains of the forest and can be audible even 5 km away!

The howler monkeys have a limb structure that prevents them from an easy life on land. So they spend most of their lives on treetops. They are so inactive that they spend almost 70 per cent of the day sleeping and can rarely be seen running or leaping. However, their strong tails function as their fifth limb serving as a climbing aid. Essentially folivorous, they adore munching on leaves all the time, with occasional servings of fruits and flowers!

According to historians, the Mayans venerated these monkeys for their beauty and worshipped them as divine beings. The black howler monkeys constantly face threats from forest destruction. They are captured and killed mercilessly for their meat and taken as captives to be kept as zoo exhibits.

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Rainforests have a wide spectrum of varied landscapes and water bodies that are perfect places for both animals and plants. Apart from providing suitable living conditions for plants, rainforests set the perfect abode for reptiles, amphibians, and mammals as well. ‘Herp’ is a term used collectively for amphibians and reptiles.

Rainforests provide a wide range of living spaces, ranging from high rocks to elevated canopies and creeks. The most common reptiles found are lizards, turtles, tortoises, venomous snakes, and crocodiles, and the amphibians found in abundance are frogs, toads, salamanders, newts, and worm-like caecilians.

The green basilisk, the common iguana, the pygmy stump-tailed chameleon, the spectacled caiman, etc. are a few of the millions of reptile species identified.

Among the amphibians, the most commonly known are the giant Chinese salamander, gladiator tree frog, green poison arrow frog, Indian purple frog, monkey frog etc.

Out of the 4000 and more frog varieties spotted across the world, 427 varieties are indigenous to the Amazon rainforests alone.

In addition to deforestation, poaching and negative climatic changes, the outbreak of a deadly, mysterious disease that has caused the extinction of hundreds of frogs and toads and which is spreading across the globe has put scientists and naturalists on their toes. Drastic measures are being taken up to devise measures to control this pandemic and save further extinction of these threatened amphibians.

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You might be wondering if this is the name of some giant grizzly bear. Well, it isn’t. The Sulawesi bear cuscus is a rare arboreal marsupial with a koala-like body, head like a possum, and is commonly called the marsupial monkey. They exist peacefully along with pigs, dwarf buffaloes, and primates and are usually located in the upper canopies of the lowland tropical rainforests of Sulawesi Island, Indonesia.

If you didn’t know, arboreal signifies animals that live on trees while marsupials are mammals whose offspring are pre-mature and cling inside the mother’s pouch until they become mature. Yes, the kangaroo is a marsupial!

Herbivorous in nature, the Sulawesi bear cuscus lives in pairs or small groups of three or four. Leaves, unripe fruits, and flowers that are low in nutrients from their diet. Hence, they are lethargic and move at a slow pace. They are known to spend most of the day lounging and resting for better digestion of food.

Their movement is so gentle that they are fondly called the forest’s ‘slow-motion acrobats’.

Sadly, large-scale poaching for their meat and fur coats, and massive deforestation have resulted in these poor creatures being listed as ‘Vulnerable Species’ by the IUCN (International Union for the Conservation of Nature).

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