Category Animal World

How Harbour seals navigate at night?

Indian and Polynesian sailors have historically been guided by lodestars to find their way at sea. But research shows that harbour seals have been doing it much before humans attempted it. Harbour seals are marine mammals. They live along the Atlantic and Pacific coastlines of the Northern Hemisphere, and hunt for food at night. Obviously, in the dark, they cannot follow the landmarks that are visible on land.

In 2006, German and Danish scientists placed two harbours seals – named Nick and Malte – in a specially constructed floating planetarium. The team trained the two to swim in the direction of specific lodestars. They discovered that the animals could identify a single star out of a projection of the Northern Hemisphere night sky. This showed that the seals followed specific lodestars as navigational aids when they swam far from the shore. Remember, this was an experiment. So do the seals in the wild navigate by following individual stars? Researchers believe they do. Star-based navigation enables the seals to efficiently search an area for food.

 

Picture Credit : Google

How birds navigate at night?

Scientists say migrating birds rely on the magnetic compass after sunset. They also use the individual stars for navigation at night. All animals with “camera eyes”, the kind of eyes humans have, can make out individual stars. Insects with compound eyes cannot do this so they see the starry sky and the Milky Way as patterns of light. But scientists do not have an answer for one question: how do birds flying at night change the point of reference when they cross the equator? How do they follow the stars that change their orientation across the equator?

One example of birds that understand stellar navigation is the indigo bunting of North America. These birds fly south for winter, and they do it at night. There is less competition for food at night and there are fewer disturbances after dark. In one experiment, researchers captured these migrating birds and placed them under a starlit dome. And this is what they found.

Indigo buntings watch the rotation of close star patterns around a centre point, such as the North Star. From this they determine the directions. Before migrating, songbirds orient themselves by hopping in the direction they want to travel. In the experiment, the starlit dome rotated around the North Star, which is what happens in the night sky. The smart birds observed it and began to fly south. Then the researchers removed the constellations within 35 degrees of the North Star. The birds became disoriented and couldn’t fly anywhere.

So, individual stars are not that important for the birds. What they need to see is the rotation of the close star patterns around a centre point. This helps them to determine where north is. They use this information to fly south.

 

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How Dung beetles navigate at night?

Whenever we talk of the navigational skills of explorers, we wonder: How did these seafarers find their way about the sea with no navigational aids like sat-nav? The answer is always the same. Sailors of olden days followed the stars. They understood star formation and aligned their route to how the stars appeared in the night sky. But man is not only the creature that “followed the stars.” Sea creatures and birds are known to have looked up to the heavens for guidance. Recent studies in this field show that dung beetles too use the stars for navigation! And they have a brain the size of a grain of wheat!

Dung beetles are African insects. During the day, the beetles walk in a straight line rolling the dung. The beetles survive because of the dung. The dun provides them with food and drink, and during the hot African noon, the beetles simply climb on the dung to keep themselves cool. So the beetle fights for the smallest bit of dung, and carries it away even during the night.

At night, moonlight is their guide. On the days the moon is not visible, dung beetles follow the Milky Way. Human, birds and sea creatures follow just the lodestar. Just one star is enough for them. But the eyes of the dung beetle are not that sharp. The Milky Way has a straight band that is easy for the beetles to follow. For the Milky Way to be seen, the sky has to be clear. So, should we not keep the sky clear, without pollution, so the poor beetles trying to cart their food do not lose their way?

 

Picture Credit : Google

How animals cope with a flaming forests?

Natural phenomenon

Wildfires or forest fires are a common natural occurrence. They start during the summer months when vegetation dries out. Lighting striking a dried tree is enough to start a blaze. Fanned by the wind, the fire spreads quickly, consuming vast areas of forest. Forest departments and firefighters have a tough job containing the fires and millions are spent and lives lost in extinguishing them.

Animals that live in regions that see frequent forest fires have evolved and adapted to live with it. Animals caught in a forest fire obviously try to escape the flames and break over. Predators seize this golden opportunity to grab a snack. Bears, raccoons, and raptors have been observed hunting down the fleeing animals.

Different species use different strategies to avoid being instantly barbecued. Birds fly away. Mammals run. Amphibians and other small creatures burrow into the ground, hide out in logs, or take cover under rocks. Other animals, including large ones like deer, or take refuge in water bodies.

Bush firefighters in Australia have frequently spotted waves of creepy crawlies rushing ahead of the fire, desperately attempting to outrun the licking tongues of flame.

Smoked out

Some animals die of smoke suffocation or are charred. These are the ones that can’t run fast enough or find suitable shelter. Not all of those creepy crawlies may escape. Young and small animals are particularly at risk and some of their strategies for escape might literally backfire. For example, a koala’s natural instinct is to crawl up into a tree and it ends up trapped.

Deep down

The heat can kill even organisms buried deep in the ground, such as fungi. Jane Smith, a mycologist with the U.S. Forest Service in Corvallis, Oregon, has measured temperatures as high as 700°C beneath in a wildfire, and 100°C a full 5 cm below the surface.

Scientists don’t know the exact number of animals that die in wildfires each year. However, there are also no documented cases of wildfires – even the really bad ones – wiping out entire populations or species.

Rising from the ashes

Landscapes burned in a wildfire don’t die. They just transform into a new habitat. This can also mean new opportunities. In some places, woodpeckers will fly in and feast on bark beetles in dead and dying trees. Black fire beetles lay their eggs only to burned-out trees since there is no sap or resin to trap the larvae when they emerge.

A disturbance like a wildfire lets an old forest be reborn. A fire sparks many changes, as plants, microbes, fungi, and other organisms re-colonize the burned land.

Water bodies in a burned area can also change. Fish may temporarily move away. There can be a short-term dying out among aquatic invertebrates, which can affect the land animals that eat them.

Woodland and grassland animals (and plants) have lived with a cycle of fire and re-growth for ages. Many species actually require fire to regenerate. Heat from the flames can stimulate some fungi, like morel mushrooms, to release spores. Certain plants will produce seeds only after a blaze.

Good or bad?

Over the past century, wildfires have often been put out quickly or prevented because they damage human habitation.

That’s led to fewer species of those trees and plants that grow only in the years after a fire. It’s also caused a fall in some animal species that depend on post-fire habitat. The Kirtland’s warbler is a small American songbird that nests only in young jack pine forests. The pine comes only release their seeds in a fire. Without fire, much of the bird’s nesting habitat has disappeared.

 

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How Capuchin monkey helping disabled?

 

Monkeys go to college

There is an organization in the USA called Helping Hands that trains capuchin monkeys to help people who are paralyzed and confined to a wheelchair

In 1977, a psychologist with Boston’s Tufts University, called Mary Willard wanted to help from who was a quadriplegic. Quadriplegic are paralyzed from the neck down. Her professor suggested she train capuchin monkeys because not only are they highly intelligent, they are also small (they weigh between 3-6 kilos) and live for more than 30 years. Their natural curiosity and tiny hands make them ideal for performing delicate tasks.

With a grant of $2000, Willard begins training capuchins. Her first trained monkey Hellion was placed with 25-year-old Robert Foster in 1979. She was with him for more than 20 years. Willard begins Helping Hands, affectionately known as Monkey College, in 1982. In the last 25 years, it has placed over 100 capuchin monkeys with needy patients. The monkeys live with foster families when they are very young for 3-5 years till they are get used to people. Then they go to the college where they are trained for a further 2-3 years to become full-fledged ‘helping hands’.

Each monkey is trained to do everyday tasks such as turning switches on and off, changing DVD’s and CD’s, picking up dropped items such as keys, pens or phones, heating food in a microwave, turning the pages of a book, fetching food and drink and even scratching a troublesome itch! Their owners either use a laser pointer to show them what to do or give verbal commands.

The capuchins are bred at the local Southwick’s Zoo. The organization spends $35,000 to train and care for each monkey. The money is raised through donations and grants. The patients receive them free of charge. After the monkeys grow old, foster families look after them.

Not only do the monkeys enable their owners to lead more independent lives, they also help these people overcome depression and loneliness.

Clever Capuchins

Capuchins are the most intelligent species of South American or New World monkeys. They are adept at observing people and imitating their actions, especially in handling objects and using tools. They are named after the order of Catholic friars called Capuchins because their cap of dark hair resembles the friar’s headgear.

Other animal helpers

Dogs are widely used as guides for the blind. Some dogs are trained to alert the deaf to fire alarms and other warning devices that use sound. Miniature horses are now popular as guides for the blind because they live longer. These guide ponies are about the size of large dogs and can be trained just as well.

 

Picture Credit : Google

How frog-fishers catch their prey?

Frog-fishers are bizarre-looking creatures. They hook their prey with an extended part of their own body that acts as bait. The strange extension of their body, known as lure, resembles a small group of dangling worms, which can regenerate if bitten off. When the fish spots its victim, it begins wiggling its lure. The unsuspecting victim, taking the lure for a meal, comes close to the mouth of the fish. Once the prey – usually a crustacean or fish – is within range, it stands little chance of survival. The frog-fish sucks in its live meal by opening its huge mouth and pulling in the prey in milliseconds. In fact, the fish has possibly the quickest movement in the world. For additional help, the fish has camouflage pattern and fin-feet to move on the sea floor. With all these “weapons”, the frog-fish can be seen as the most formidable predator.

 

Picture Credit : Google