Category Zology

WHAT IS A GHARIAL?

Gharials are also reptiles in the Crocodylidae family. They live in fresh water, and are only found in parts of India and Nepal. A long, sleek snout that displays rows of very sharp, flesh-tearing teeth, and a bulbous lump on the male’s snout make them different from their cousins. Gharials can grow up to six metres in length.

Physical Description

The gharial is one of only two species in the Gavialidae family. It  has a characteristic elongated, narrow snout, similar only to the tomistoma (previously called the false gharial). Many sharp, interlocking teeth line the gharial’s elongated jaws.

Gharials exhibit sexual dimorphism — or differences in characteristics between males and females of the same species — in both size and appearance. Adult males develop a bulbous growth at the tip of their snout, called a “ghara” after the Indian pot it resembles. The ghara has several functions. It partially covers the crocodiles nostrils and acts as a vocal resonator, creating a loud, buzzing sound when the gharial vocalizes. It is also a visual signal for females, helping males attract a mate.

Because of their weak leg muscles, gharialsare poorly equipped for locomotion on land. Most of their movement takes place in the water. When they do move across land, gharials push their bodies forward across the ground, a motion known as belly-sliding.

Size

The gharial is one of the largest of all crocodilian species, with males reaching 16 to 20 feet (5 to 6 meters) in length. Females typically grow to lengths of 11.5 to 15 feet (3.5 to 4.5 meters).

Native Habitat

Historically, the gharial’s range spanned rivers of Bangladesh, Bhutan, India, Myanmar, Nepal and Pakistan. Today, only fragmented populations remain in Nepan and northern India.

Gharials are adapted to an aquatic lifestyle in large rivers, and individuals typically only leave the water to bask and nest on sandbanks.

Food/Eating Habits

Adult gharials primarily eat fish, while juveniles also feed on insects, crustaceans and frogs. The crocodile’s unique snout, along with its sharp, interlocking teeth help it capture prey, quickly striking at fish in the water. At the Smithsonian’s National Zoo, gharials eat a variety of fish.

Reproduction and Development

Like other crocodilians, gharials are polygamous, with one male defending a territory where he and several females live. Territorial and courting display behaviors include head slapping the water and buzzing vocalizations. Females reach sexual maturity when they are approximately 9.8 feet (3 meters) in length, and males at about 13 feet (4 meters). Mating typically occurs in December and January.

Females dig a nest during the dry season, between March and April, and deposit an average of 40 eggs, which hatch from 60 to 80 days later. As with all crocodilians, the sex of the hatchlings is determined during incubation.  Females, who are protective of their nest and hatchlings, provide the sole parental care.

Credit : Smithsonian’s national zoo & conservation biology institute 

Picture Credit : Google 

WHICH BIRDS CAN FLY NON-STOP OVER LAND AND SEA, IN SEARCH OF FOOD AND WARMTH?

Here’s a closer look at some of the birds that perform great feats of endurance by flying non-stop over land and sea in search of food and warmth.

The Arctic tern

The bird that probably sees more daylight than any other creature in the world is the slender, graceful relative of the seagull, the Arctic term. This 33- to 35-cm-long bird makes the most spectacular migration, travelling over 35,000 km every year. It breeds in the Arctic summer and then flies south, reaching in time for the Antarctic summer!

The terns breed on the Arctic coasts of Alaska, Greenland, Canada, Europe, and Siberia, some nesting within 700 km of the North Pole. They raise their young on the abundance of insects and fish during the short-lived Arctic summer when the sun almost never sets. As winter closes in, they begin flying south. After a journey halfway around the globe, they gorge on the small fish and plankton of the Antarctic ocean throughout the southern summer- once more in almost perpetual daylight!

Shining bronze cuckoo

The Arctic term is not the only avid seeker of the sun. Though it may be the long-distance migration champion, there are other birds that perform greater feats of endurance by flying non-stop over land and sea in search of food and warmth.

The fledglings of the shining bronze cuckoo are abandoned by their parents. With no adult bird to guide them; they fly out each March from their breeding grounds in New Zealand.

They accurately follow the path of their parents to Australia, and from there, turn northwards to Papua New Guinea and the Bismarck Archipelago. Out of the total distance of 6,400 km, 2,000 km is over open sea! One mistake can be fatal, for the birds cannot swim.

Ruby-throated hummingbird

The ruby-throated hummingbird flies 800 km non-stop across the Gulf of Mexico to South America every autumn. Scientists are baffled, because the bird weighs just 3.5 gm, not enough to store so much energy.

What guides birds across such distances so accurately? Scientists discovered in 1977 that deposits of magnetic iron oxide in the skulls of migratory birds may act as a built-in compass. Some believe that the instinct to migrate maybe encoded in the genes, compelling the birds to behave as their ancestors did, even without apparent reason.

Picture Credit : Google 

WHAT IS CRYPTOZOOLOGY?

It is the study of animals whose existence has not been proved or documented by mainstream Zoology. Such animals include creatures from myths and legends such as Bigfoot, the Loch Ness Monster, and the Yeti, among many others. Cryptozoology also involves searching for living members of extinct species such as dinosaurs. All these animals are collectively called ‘cryptids’.

The search for cryptids is largely based on alleged sightings and stories; the lack of concrete evidence has kept cryptozoology from being recognised as a true branch of science. However, cryptozoologists argue that several animals like the okapi, giant squid, the mountain gorilla, and so on, were deemed cryptids before their existence was brought to light. Although examples of such successes are few and far, the prospect of unravelling more mysteries of nature continues to give cryptozoology a huge following.

Picture Credit : Google 

WHAT ARE KEYSTONE SPECIES?

Keystone species play a unique and crucial role in the functioning of an ecosystem. The animals and organisms that come under this category help to maintain biodiversity within their community either by controlling populations of other species that would otherwise dominate the community or by providing critical resources for the survival of a wide range of organisms.

These species act as the glue that holds the system together. The term was coined by Dr Robert Paine in 1969, to describe the power a single species exerts on an ecosystem. Examples of keystone species include starfish, sea otters, beavers, wolves, elephants, prairiedogs and bees.

Keystone Species Examples

Sea Otter

The sea otter (shown below) is considered a keystone species as their consumption of sea urchins, preventing the destruction of kelp forests caused by the sea urchin population. Kelp forests are a critical habitat for many species in nearshore ecosystems. In the absence of sea otters, sea urchins feed on the nearshore kelp forests, thereby disrupting these nearshore ecosystems. However, when sea otters are present, their consumption of sea urchins restricts the sea urchin population to smaller organisms confined to protective crevices. Thus, the sea otter protects the kelp forests by reducing the local sea urchin population.

Large Mammalian Predators

While small predators are important keystone species in many ecosystems, as mentioned above, large mammalian predators are also considered keystone species in larger ecosystems. For example, the lion, jaguar (shown below), and gray wolf are considered keystone species as they help balance large ecosystems (e.g., Central and South American rainforests) by consuming a wide variety of prey species.

Sea Star

Sea stars (shown below) are another commonly recognized keystone species as they consume mussels in areas without natural predators. In many cases, when the sea star is removed from an ecosystem, the population of mussels proliferates uncontrollably, and negatively effects the resources available to other species within the ecosystem.

Credit :  Biology dictionary  

Picture Credit : Google 

WHAT TYPE OF RELATIONSHIP DOES THE MACULINEA ALCON BUTTERFLY HAVE WITH THE ANTS?

Did you know there is a species of butterfly, Maculinea alcon, that can trick the Myrmica ants into taking care of their young? The butterfly’s caterpillar feeding off plants drop to the ground and wait to be picked up by the passing ant. Its waxy coat secretes chemicals that mimic those found on the ants. Mistaking it for one of its own, the ant takes it to its nest where it’s taken care of by other ants.

Studying  Maculinea alcon, a beautiful blue butterfly, in the marshes of Denmark, David R. Nash and colleagues found that Alcon butterflies fool Myrmica ants into raising their young, by having larvae with an outer coating that mimics that of the ants. The ants care for the Alcon blue butterfly caterpillars — an ant colony parasite — to the detriment of their own offspring.

The researchers say the observed differences in patterns of surface chemistry of caterpillars between locations “indicate an ongoing coevolutionary arms race between the butterflies and Myrmica” ants.

“The more closely the butterfly mimics the ant cuticle’s hydrocarbon chemistry, the more successful the butterfly is in attracting the ants, but this varies from location to location,” explained a statement from Science Express.

Nash and colleagues say the findings should be considered when reintroducing the threatened Alcon blue butterfly into the wild.

Credit : Mongabay

Picture Credit : Google 

WHICH IS THE SMALLEST BAT IN THE WORLD?

Kitti’s hog-nosed bat or bumblebee bat is the world’s smallest mammal and the world’s smallest bat. Weighing just 1.7-2.0 gms, with a head-to-body length of 1.14-1.29 inches and a wingspan of 5.1-5.7 inches, the bat is found only in a select few limestone caves on Khwae Noi River in Kanchanaburi Province of southwest Thailand.

The population of the bats is very small and the slow reproduction of the species can form a problem in the future. Females of the Bumblebee bats are giving birth just once a year during the summer in April. For a long time their recently born youngster will stay attached to the belly of its mom. It takes quite some time before the wings of the super tiny bat are well-enough developed to fly. The slow reproduction of the spices can become a threat for the future as places were (and still are) disturbed by scientists, tourists, monks and new developments like the deforestation and a new pipeline being built from Thailand to Myanmar. However it is hard to tell to which extend these developments will affect the population of the species. Many caves – inhabited by the Bumblebee bat – are hard to access; therefore it is difficult to estimate their total population.

Not like other bat species, these bats are only seen in very small groups of sometimes just 10 bats. Larger groups are consisting of 100 to max. 500 Bumblebee bats. The bats are to be found in limestone caves mostly located close to the river, as it provides the tiny bats with many insects. They are also living in the forests but it is very difficult to spot them there. So-far the tiny bat is spotted in Kanchanaburi, the West of Thailand and since 2001 the bat is also discovered in a Southeast region of Myanmar. In Thailand’s Bumblebee bats are living in the caves along the river Kwai and in the Sai Yok National Park. If you want to see this little guy you may be lucky at the Lawa Cave near the river Kwai. Close by accommodations are the River Kwai Resotel (a stylish bungalow resort) or the Float House (luxurious floating on the river Kwai).

Credit : River Kwai Resotel 

Picture Credit : Google