Category Zology

Which is the largest animal on Earth?

Blue whales are the biggest animals that have ever inhabited our planet. These marine mammals grow up to 22 metres in length and to a weight of 150,000 kilograms. Their tongues alone weigh as much as an elephant in some cases and their hearts can be as big as an automobile.

The most interesting detail about these huge creatures is the fact that they reach these immense body sizes by consuming tiny shrimp-like animals called krills alone. In some seasons, a single adult blue whale eats about 4000 kilograms of krill a day.

Blue whales belong to the family of baleen whales. Baleen is a fringed plate made of fingernail-like material that is attached to their upper jaws. These giant animals feed by first gulping a great amount of water through their mouth and then they expand the pleated skin on their throat and belly to take it in. After this, the whales use their massive tongue and force the water out through the thin, overlapping baleen plates. This process leaves behind a large volume of krill, which gets consumed by the whales. Blue whales are found in all the oceans, except the Arctic. They occasionally swim in small groups but they move about in pairs or stay alone.

They now face a severe threat due to whaling and are considered endangered according to the IUCN Red List.

Picture Credit : Google

Birds with an aesthetic sense?

Did you know that bowerbirds are famous for building elaborate structures and even decorating them? Read on to know fascinating facts about the species.

The early European explorers to Australia and New Guinea thought that the elaborate structures they sometimes came across in the forests were built by Aborigines, so artistic and skilled were they. Imagine their surprise when they found that a species of bird was responsible!

The bird is called a bowerbird because of its habit of making complicated ‘bowers’ or places of courtship to attract and impress the females. The males spend weeks setting up and decorating their bowers. A young male may take several years to perfect the technique.

There are 20 species of bowerbirds of which the satin bowerbird of Australia builds the most elaborate bower. The remarkable structure it builds may reach up to 2.7 m in height. It may consist of a tower of twigs arranged around a central sapling or resemble a miniature house, complete with a door and thatched roof!

Other species clear an area in the forest and set up an ‘avenue’ or domed tunnel of sticks with just enough space for the bird to enter. Some prepare a lek or display area spread with upturned leaves or ’tiled’ with rocks.

Several species give their bowers a coat of paint, using charcoal mixed with saliva or the natural pigment contained in the juice of wild berries. A piece of bark fibre or a tuft of leaves held in the beak serves as a ‘paintbrush’. Not content with this, a bowerbird may bring coloured stones, feathers, leaves and flowers to add to the decoration. Iridescent insect skeletons, spider webs and snail shells serve as extra adornment.

Modern-day bowerbirds use discarded buttons, toys, empty tins, coloured straws, broken glass, and even CDs for this purpose! The floor of the bower is often strewn with an enticing bed of soft, fresh leaves.

When the male bowerbird is satisfied with his handiwork, he lures the female inside by calling loudly and when she shows interest, with a dance display. Most male bowerbirds play no part in raising the young. The female lays eggs, which she will incubate by herself. She also cares for the brood on her own.

Quick facts

  • There are 20 different bowerbird species, and the males come in colours ranging from green, orange, red, yellow and black to white, olive-brown and sooty grey. Some have a brilliant crest or a ruff. Females are comparatively dull
  • Bowerbirds live in tropical forests, mangroves, eucalyptus groves and savanna woodlands.
  • They can imitate the calls of other species, as also machines like a chain saw.
  • Satin bowerbirds may reuse and refurbish the same bower for more than 30 years.
  • Different species go for different colours. The striped gardener bowerbird prefers yellow, red, and blue objects, while the fawn-breasted bowerbird favours green
  • Bowerbirds may kill insects solely for the purpose of decorating Competition for females is fierce.
  • The birds fight for choicest pieces, steal baubles from each other and tear apart their rivals’ bowers.
  • Researchers think that they are the only animal species besides humans to have an aesthetic sense.

Picture Credit : Google 

How do we know that humpback whales communicate through songs, or about the sounds that pervade the ocean depths?

How do scientists know that humpback whales communicate through songs? That’s because they have ears placed on the bottom of the ocean at strategic points! These ‘ears’ are part of a network of underwater microphones or hydrophones placed by various scientific research organisations that eavesdrop on the sounds that pervade the inky depths-from the squeaky whistles and moans of whales and the rumbling of earthquakes, to the drone of ships passing overhead.

The sounds provide a lot of information about the world beneath the waves. The information can reveal how man-made noise affects the creatures of the deep as well as predict if the movement of tectonic plates is going to cause an earthquake.

Sound travels much further than any other form of energy in the ocean, with low-frequency sound reaching thousands of kilometres deep. Data collected from hydrophones shows that shipping activity cripples communication between whales and other marine mammals that use sound and echolocation to find their mates, fellows, and prey. The noise from ships is so loud that these animals are forced to ‘shout to be heard! According to a diver, the disturbance caused by a ship passing above is like being hit in the chest with a heavy golf club.

Data collected from hydrophones shows that shipping activity cripples communication between whales and other marine mammals that use sound and echolocation to find their mates, fellows, and prey.

Picture Credit : Google 

How powerful is a harpy eagle?

Harpy eagles are America’s most powerful birds of prey that live in the tropical rainforest. They are a key bio-indicator, meaning if there are good numbers of harpies in the forest, then it is certain that there is a healthy number of its prey species.

In Greek mythology, the harpy was a terrifying creature with the body of an eagle and the face of a woman. Harpies flew about in flocks and had a foul smell and sharp claws.

The aptly named harpy eagle of Central and South America has a piercing gaze and fan-like crest that give it a fearsome look. It has dark slate-grey plumage. with lighter grey feathers on its head and face. A broad bib of black separates its head and underside. Its belly and legs are a startling white.

Harpies are America’s most powerful birds of prey, though not the largest (that title is held by the Andean condor). They live in the tropical rainforest, and unlike eagles that live in the open, they prefer to hunt just beneath the canopy – this in spite of having a wingspan of around 2.5 m! The wings are shorter and broader than those of other eagles to facilitate hunting among the trees. As with most eagle species, female harpies are almost double the size of males.

These fascinating eagles are extremely dexterous fliers and at the top of the food chain wherever they live. Harpies can weave in and out of branches and pluck unlucky sloths and monkeys off like ripe fruit with their wickedly curved, razor sharp talons. The back talons are longer than those of a grizzly bears at 13 cm. Sloths and monkeys are the females’ favourite food but the males prefer the smaller opossums, fawns, snakes, iguanas, and even porcupines.

A harpy eagle can perch silently for hours and hours, waiting for a meal. It can fly almost vertically, so it can attack from below as well as drop down from above. It can turn its head upside down to get a look at its prey as it zooms in. Its keen eyes can spot something as small as two cm in size from 200 metres away.

Harpy eagles are elusive and rarely seen, though their range is very wide. They are near-threatened due to logging and agriculture. No one knows how many remain in the wild – scientists believe the number could be between 20,000 and 50,000.

Fact file

  • Harpies build huge nests measuring around 1.2 m wide and 1.5 m long, big enough for a person to lie in!
  • The birds mate for life, and once a nest is built, an eagle pair may reuse and repair the same nest for many years.
  • Harpy eagles are usually quiet but they can wail, croak, whistle, click, and mew.
  • Monkeys and sloths may weigh up to eight kg but a harpy’s talons can latch on with a pressure of over 50 kg. This is bone-crushing, and the victim dies instantly.
  • Chicks are pure white and attain adult colouring at the age of three. The harpy is Panama’s national bird.
  • The eagle is a key bio-indicator. That is, if there are good numbers of harpies in the forest, then it is certain that there is a healthy number of its prey species.

Picture Credit : Google 

On a wild python chase

Articles on animal numbers dwindling may often include hunting as one of the reasons. Over the last few centuries, several creatures – large and small, and marine and land dwelling have been pushed to the brink of extinction due to mindless hunting. But here’s a species whose killing has been actively taken up and encouraged. Why? Come, let’s find out.

Among the largest of snakes, Burmese pythons are native to Asia. However, in the 1990s, thanks to the pet trade, thousands of them found homes in the U.S. It is said that over the years, many either escaped into the wild or were released there by the pet owners themselves who found it difficult to keep the snakes. When Hurricane Andrew stuck Florida in 1992, it is believed that several snakes escaped a python-breeding facility and found refuge in Everglades, a massive wetland in southern Florida. And, today they’ve turned into an invasive species. Large as they are – growing up to 20-odd feet, they feed on large mammals such as pigs and goats. Famously, or rather infamously, way back in 2005, a python tried “to swallow an alligator and exploded in the park, leaving both the predators dead”. In the last few decades, the snakes have decimated native wildlife populations of foxes, rabbits, raccoons, opossums, deer, etc., and are irrevocably altering Everglade’s ecosystem.

Considering how vast Everglades is – about 20,000 sq km, and that there are thousands of pythons out there, the authorities are constantly looking for ways to capture the snakes or control their population. In fact, cash is rewarded to those who hunt them. Even a month-long competitive hunt has been organised in the hope that the wetlands would be rid of these non-venomous reptiles.

Though Burmese pythons continue to wreak havoc in another continent, back in their native range, the story is different. They face several threats, and their numbers are declining due to habitat loss, pet trade, and use in traditional medicine. Sadly, they are listed as Vulnerable on the IUCN Red List.

Did you know?

A few years ago, two Indians – Masi Sadaiyan and Vadivel Gopal – belonging to Tamil Nadu and from the Irula tribe known for its exceptional snake-catching skills, were flown to Everglades. Within a month, the duo had caught 27 pythons. This is an impressive number considering a month-long python hunting competition in 2016 comprising 1,000 hunters managed a haul of only 106!

Picture Credit : Google 

Elusive hummingbird species spotted in Colombia

An elusive and rare hummingbird has been rediscovered in Colombia by a birdwatcher. The hummingbird Santa Marta sabrewing has been spotted years after it was first recorded in 2010. The news has sent ornithologists across the world into a state of excitement as they celebrate the find.

This is the third time that the species has been documented. It was first documented in 1946 and later in 2010 when the researchers captured pictures of the species in the wilderness.

The bird was spotted by Yurgen Vega during a survey of the endemic birds in the Sierra Nevada de Santa Marta. The researcher said that the sighting was a complete surprise and that he was overwhelmed with emotion when he first spotted the bird.

The hummingbird Santa Marta sabrewing, which is only found in the Sierra Nevada de Santa Marta mountains of Colombia was thought to have gone extinct by many ornithologists. This species of hummingbird has been listed on the IUCN red list of threatened species ‘as critically endangered’. The bird also figures in the Top 10 ‘most wanted’ list of the ‘Search for Lost Birds’ initiative of conservation organisations.

The hummingbird spotted by Yurgen Vega was male. The bird is identified by its emerald green feathers, bright blue throat and curved black bill The bird was spotted to be singing and vocalising. Scientists associate this behaviour to either courtship or defending territory.

John Mittermeier, director of threatened species outreach at the American Bird Conservancy has likened the rediscovery to “seeing a phantom”.

The species is believed to live at an altitude of 1200 to 1800 metres in the neotropical forest. During the rainy season, they are known to migrate in search of flowering plants.

The Sierra Nevada de Santa Marta in northern Colombia is rich with wildlife and home to 24 bird species that aren’t found anywhere else. Yet, according to scientists, only 15 per cent of the habitat is intact. The spotting of the hummingbird has further intensified the call to protect these forests which can solely aid in the conservation of the rare species dwelling there.

Armed with this information, the scientists will now focus on identifying stable populations of this species which can help them come up with conservation strategies and learn more about the bird.

What’s the IUCN Red List?

The International Union for Conservation of Nature’s Red List of Threatened Species is an indicator of the health of the biodiversity in the world. The global conservation status of animals, plant species and fungi are covered under this. The list indicates the conservation status of the species and helps in formulating conservation plans. It gives information such as the habitat, population size, ecology, threats the species faces and so on. At present, there are more than 147,500 species on the IUCN Red List of which more than 41.000 species figure under the “threatened with extinction” category.

What’s ‘Search for Lost Birds’

A joint initiative of conservation organistaions Rewild’, ‘American Bird Conservancy (ABC) and ‘Bird Life International’, the Search for Lost Birds’ attempts to find 10 species that haven’t been observed in the wild for over a decade but do not figure in the extinct category of IUCN Red List of Threatened Species.

Picture Credit : Google