Squirrel

Order : RODENTIA
Family : Sciuridae
Species : Ratufa bicolor

 Head-Body Length : Up to 40 cm
Tail Length : Up to 50 cm
Weight : Up to 1.6 kg ?
The beautiful Black Giant Squirrel is one of the largest squirrels in the world. It inhabits tall primary forest and generally remains high in the canopy, but at times may be found at lower levels when feeding. It is largely  solitary in habits and extremely shy, rarely coming to ground. It can confidently make huge leaps from branch to branch in the high canopy.
Its upperparts and tail are jet black, but the cheeks, chest, front of the forelimbs and underparts are  cream or orange. The tail is long and dorso-ventrally flattened.
Fruits, seeds and young leaves make up its diet, supplemented by occasional insects and sometimes birds eggs. It builds a large, spherical nest of leaves and twigs.
The species once ranged extensively from Nepal and Assam through Burma, Indochina and Thailand to Peninsular Malaysia, Sumatra, Java and Bali.  Its numbers have declined with the large-scale clearance of primary forest. It is absent from Singapore.

snake

Big snake


An afternoon snorkel off Catalina Island brought a local instructor face-to-face with the half-dollar-sized eyes of an 18-foot sea creature on Sunday.
Marine science instructor Jasmine Santana was shocked to confront the rare oarfish in the waters of the island’s Toyon Bay, about 2 miles from Avalon and 22 miles off the Port of Los Angeles.
It was the “discovery of a lifetime,” according to a news release issued by the Catalina Island Marine Institute, for which Santana is an instructor.
snake-like fish was found late Sunday afternoon dead but nearly completely intact and appeared to have died from natural causes, according to the release.
“It took 15 or 20 of us to pick it up,” said Jeff Chace, a program director with CIMI, which runs a camp out of Toyon Bay that teaches children to snorkel, kayak and hike.
Instructors from CIMI were unloading gear from a trip to Santa Barbara Island when they spotted Santa pulling the oarfish ashore.
“The craziest thing we saw during our two day-journey at sea happened when we got home. These islands never cease to amaze,” instructor Connor Gallagher said, according to the news release.
The oarfish, which can grow to more than 50 feet, is a deep-water pelagic fish — the longest bony fish in the world, Chace said. It’s very rare to see so close to shore, he said.
“It’s one of these rare weird things you see in Southern California,” Chace said.
The fish is believed to dive more than 3,000 feet, and in part because of the deepwater habits, little is known about them, Chace said.
Children at the camp and the self-professed “science nerd” employees were able to get a good look at the fish, which had been pulled up onto the beach at Toyon Bay, Chace said.
Now CIMI is trying to figure out what to do with the silverly fish’s body. The program has been in touch with a “fish guru” at UC Santa Barbara and with the Museum of Natural History in LA, Chace said.
“We can’t even really fit it into our freezer,” he said.
The scientists may decide to bury the carcass and let it decompose under the sand. In the end, they’d have an 18-foot long skeleton to show for their unexpected discovery.

The World's Biggest Planes

The World's Biggest Planes

When Orville and Wilber Wright took to the skies in North Carolina, they made it 120 feet. They could have taken off and landed on the wings of the world’s biggest cargo plane.
The An-225 Cossack aircraft (wingspan 291 feet, 2 inches) was built to transport the Soviet Union’s Buran orbiter, their equivalent of the U.S. Space Shuttle. Only two were ever made, and just one is still flying.
The Buran is the kind of load the world’s biggest aircraft are called on to haul. They’re not normally, well, normal. They aren’t mass produced, and they often have limited lives (think Howard Hughes’ Spruce Goose–the largest plane ever made, which flew just once).
But that’s changing. New technologies, including composite airframes, lighter engines and advanced avionics and design systems, are bringing a huge new generation of giants to life.
When the Airbus A380 enters service it will become the second-largest plane in the world and largest passenger aircraft. Built by EADS, it weighs in at 652.5 tons, is 239 feet long and has a fuselage 23 feet, 5 inches in diameter. Its four engines deliver about 300,000 horsepower. It has a maximum capacity of 840 people but may be configured for less. All this for $275 million.
The A380 has been plagued by delays and problems in production–another thing these monsters have in common. The first commercial flights are expected to begin in October, 2007 after Singapore Airlines takes delivery.
Boeing has continued to upgrade its 747 in response to the Airbus challenge and with a slight twist brought out its smaller 787 Dreamliner aircraft with an increased fuel-saving design. It has been designed and built in various load capacities ranging from 210 passengers up to 330–small by Airbus standards.
Next up could be the Boeing Pelican, an experimental concept aircraft from Boeing Phantom Works that makes everything else seem small. It has a proposed wingspan of 500 feet and a wing area that is more than an acre. It would, if built, be able to lift 1,400 tons of goods. It is referred to as the Ultra Large Transport Aircraft.
Also in design: the Fozzie, a concept plane by Boeing Phantom Works. It explores the idea of a low-fuel-use plane that uses open-rotor engines mounted on what is called a Pi-tail in the stern of the ship. The wings, being free of engines, have advantages aerodynamically. Despite a fuel-saving concept the plane is designed to go at a speed of 450 mph.
Both would dwarf the previous generation of giants. Driven by the Cold War, the last century saw the U.S. and Soviet Union playing a continual game of oneupmanship with airborne titans.
Beyond the An-225 Cossack, the results for the Russians included the KM Caspian Sea Monster or Ekranoplan. It flew only a few feet above the water and was a familiar Cold War sight flying over the Caspian Sea. It was very long at 348 feet and with a short wingspan of 131 feet, which suited its function. It weighed a hefty 1,080,000 pounds.
The U.S. had, and still has, the C-5 Galaxy. This giant was the world’s largest operating airplane when it was rolled out in 1968, and is still in use by the U.S. Air Force today. It weighs 840,000 pounds and is 247 feet, 10 inches long, with a wingspan of 222 feet, 9 inches. Its purpose: to haul military hardware, including tanks, anywhere in the world.
But nothing outdid the Hughes H-4 Hercules, or Spruce Goose. Made primarily of birch plywood (despite the nickname) it remains the largest plane ever flown. The plane weighed 400,000 pounds, plus the weight of Hughes’ ego. It still has the longest wingspan of any plane ever built, 320 feet. It only flew once and was piloted by Hughes for a mile–44 times farther than the Wright Brothers got.

Mi-26

Mi-26


Mi-26, as well as its its foregoer Mi-6, was intended for transportation of military equipment, armory, food, troops with their equipment and armament, for medical evacuations and, in special case, for tactical landings.
It was the first Soviet helicopter of the third generation. In the end of the 60s-70s many foreign companies were designing innovative helicopters, but Mi-26 was significantly superior to both domestic and foreign rates of helicopters with a cargo compartment.
Almost at the same geometrical dimensions as that of the Mi-6, the new vehicle had twice bigger payload and significantly better performance characteristics. But it didn’t affect the take-off weight of the helicopter.
They had been working much with the project trying to find reasonable solutions, constructions of some parts were repeatedly redesigned.
In 1974 they already knew what Mi-26 is going to be. Almost all systems of the power unit were located over the cargo compartment. In the nose part of the fuselage there was a cabin with seats for a left pilot, right pilot, navigator and a mechanic and a cabin for four persons who accompanied a cargo and one more mechanic.

Do Dolphins Sleep Talk in Whale?

Do Dolphins Sleep Talk in Whale?

The study estimated the body size of hundreds of species in 28 different orders of animals in 20 time periods over the past 70 million years.
The researchers used teeth, skulls and limb bones to work out the size of the animal, based on comparisons with current day species.
The researchers found it took whales 5 million generations, or 30 million years, to go from 25 kilograms to 190 tons -- the weight of a blue whale.
By contrast land mammals got bigger half as quickly as marine mammals.
For example, it took 10,000 million generations for a mammal to get 5000 times bigger, and over twice as long to evolve form the size of a mouse to the size of elephant.
Elephants have been the largest land animal for the past 10 million years, and before that the record was held by a now-extinct rhino-like animal, says Evans.
The researchers believe one reason for this faster evolution in size among marine animals is that it's easier to grow bigger in the sea.
With the water holding you up, fewer body modifications are required to handle the increase in weight.
Interestingly the new study found that almost all mammals are smaller today than they were in the last major ice ages -- a million or so years ago.
Evans says this may be because the biggest animals have been hunted to extinction, or because the weather is warmer and there is less advantage to being big.
But the blue whales are an exception, he says. "It's continued to get bigger," says Evans.
NEWS: Will 2012 Be the Year of the Whale?
He says ocean currents boosting the amount of krill around the Antarctica are likely to be responsible for this growth.
Co-author zoologist Dr Erich Fitzgerald of Museum Victoria says whales in general have continued to get larger and could theoretically continue to grow assuming they could get the food they require.
But he says the future is uncertain given such things as overfishing, which threatens whales' food source.
"Their maximum size may be peaking during our lifetime," says Fitzgerald.
Evans says there are certain advantages to increasing in size.
For example, your relative metabolic rate decreases with size which means you don't have to eat as much food per gram of your own tissue. "It's more efficient to be big," he says.
This means you can eat more abundant low energy-dense foods, like trees, leaves and grass.
And you can avoid being eaten by other animals, can store more energy and can travel further distances.
Small animals by contrast have a high metabolic rate and need to eat insects, seeds and fruit, which are less available.
But not all mammals got larger after the demise of the dinosaurs. Some, especially those isolated on islands, got smaller -- including now extinct dwarf mammoths off the coast of California and dwarf elephants in the Mediterranean.
Getting smaller can have advantages too, adds Evans, including helping animals to adapt to a smaller food resource.
Interestingly, these animals evolved smaller size much faster than those evolving larger size, the researchers found.

Blue Whales

Blue Whales



LOUDNESS
Blue whales are the loudest animals on Earth! Their call reaches levels up to 188 decibels. This low-frequency whistle can be heard for hundreds of miles. The blue whale is louder than a jet, which reaches only 140 decibels! Human shouting is 70 decibels; sounds over 120 decibels are painful to human ears. 


SKIN, SHAPE AND FINS
The blue whale's skin is usually blue-gray with white-gray spots. The underbelly has brown, yellow, or gray specks. During the winter in cold waters, diatoms stick to the underbelly, giving it a yellow to silver- to sulfur-colored sheen; they are sometimes called "sulfur bottom." 

They have a very small, falcate (sickle-shaped) dorsal fin that is located near the flukes (tail). Blue whales have long, thin flippers 8 feet long (2.4 m) and flukes that are 25 feet (7.6 m) wide. 

DIET AND BALEEN
Blue whales (like all baleen whales) are seasonal feeders and carnivores that filter feed tiny crustaceans (krill, copepods, etc.), plankton, and small fish from the water. They are gulpers, filter feeders that alternatively swim then gulp a mouthful of plankton or fish - they lunge into dense groups of small sea organisms (krill or tiny fish) with an open mouth. 50 to 70 throat pleats allow the throat to expand a great deal, forming a gular pouch. The water is then forced through the baleen plates hanging from the upper jaw. The baleen catches the food, acting like a sieve. 
The blue whale has about 320 pairs of black baleen plates with dark gray bristles in the blue whale's jaws. They are about 39 inches long (1 m), 21 inches wide (53 cm), and weigh 200 pounds (90 kg). The tongue weighs 4 tons (3.8 tonnes). 
An average-sized blue whale will eat 2,000-9,000 pounds (900-4100 kg) of plankton each day during the summer feeding season in cold, arctic waters ( about 120 days). 
SOCIAL GROUPS 
Blue whales live individually or in very small pods (groups). They frequently swim in pairs. 
DIVING
Blue whales can dive for up to an hour, going to a depth of 350 feet (105 m). 
SPOUTING - BREATHING
Blue whales breathe air at the surface of the water through 2 blowholes located near the top of the head. They spout (breathe) about 1-4 times per minute at rest, and 5-12 times per minutes after a deep dive. Their blow is a single stream that rises 40-50 feet (12-15 m) above the surface of the water. 

SPEED
Blue whales are very fast swimmers; they normally swim 3-20 mph (4.8-32 kph), but can go up to 24-30 mph (38-48 kph) in bursts when in danger. Feeding speeds are slower, about 1-4 mph (1.6-6.2 kph). 
VOCALIZATION
Blue whales emit very loud, highly structured, repetitive low-frequency sounds that can travel for many miles underwater. They are probably the loudest animals alive, louder than a jet engine. These songs may be used for locating large masses of krill (tiny crustaceans that they eat) and for communicating with other blue whales, especially in order to attract and find mates 
HABITAT AND RANGE
Blue whales live at the surface of the ocean and are found in all the oceans of the world. 

World's largest chocolate bar

World's largest chocolate bar weighs in at six tonnes 

Even the most dedicated chocoholic would struggle to get their teeth into this monster bar.
Weighing almost six tonnes and measuring 13ft (4m) square, the giant slab of milk chocolate has officially broken the record for world's largest chocolate bar.
It has been created by Thorntons in honour of the company's 100th birthday and, after months of top-secret cooking, the 12,770lb (5,792.5kg) treat was unveiled in front of staff and visitors at the confectioner's headquarters in Alfreton, Derbyshire, today.
Paul Bell, a stock controller in Thorntons' toffee department, came up with the idea to celebrate the centenary and said creating it was no mean feat.

"As you can appreciate, it was a massive task," he said.
"On pouring day itself there were over 50 people involved pouring the chocolate into the mould and it took 10 hours to do it, then a further three days to cool off."
Mr Bell, 34, from Heanor, was the first person to pour a bucket of chocolate into the stainless steel mould and said the recipe was exactly the same as Thorntons standard milk chocolate. An average bar weighs around 2.8oz (80g).
Guinness World Records adjudicators visited the factory and confirmed it had broken the record for the world's biggest chocolate bar, Mr Bell said.
Four weeks ago a company in America threatened to take the title when it created a similar mammoth block but fell short with its 12,125lb (5,500kg) effort.

The record-breaking chocolate bar will not go to waste.
Mr Bell said it will be broken up with axes and given to Thorntons staff and customers in shops, as well as helping to raise money for charities.
Being surrounded by chocolate has not put Mr Bell off.
"I'm never sick of the sight of chocolate," he said.
"That's one of the perks of the job - you can have one every day, as long as you're within reason, of course."



The World's Biggest Planes

The World's Biggest Planes

The Antonov An-225 Mriya is a strategic airlift cargo aircraft, designed by the Soviet Union'sAntonov design Bureau in the 1980s. When Orville and Wilber Wright took to the skies in North Carolina, they made it 120 feet. They could have taken off and landed on the wings of the world’s biggest cargo plane.
The An-225 Cossack aircraft (wingspan 291 feet, 2 inches) was built to transport the Soviet Union’s Buran orbiter, their equivalent of the U.S. Space Shuttle. Only two were ever made, and just one is still flying.
The Buran is the kind of load the world’s biggest aircraft are called on to haul. They’re not normally, well, normal. They aren’t mass produced, and they often have limited lives (think Howard Hughes’ Spruce Goose–the largest plane ever made, which flew just once).
But that’s changing. New technologies, including composite airframes, lighter engines and advanced avionics and design systems, are bringing a huge new generation of giants to life.
When the Airbus A380 enters service it will become the second-largest plane in the world and largest passengerAn aircraft. Built by EADS, it weighs in at 652.5 tons, is 239 feet long and has a fuselage 23 feet, 5 inches in diameter. Its four engines deliver about 300,000 horsepower. It has a maximum capacity of 840 people but may be configured for less. All this for $275 million.
The A380 has been plagued by delays and problems in production–another thing these monsters have in common. The first commercial flights are expected to begin in October, 2007 after Singapore Airlines takes delivery.
Boeing has continued to upgrade its 747 in response to the Airbus challenge and with a slight twist brought out its smaller 787 Dreamliner aircraft with an increased fuel-saving design. It has been designed and built in various load capacities ranging from 210 passengers up to 330–small by Airbus standards.
Next up could be the Boeing Pelican, an experimental concept aircraft from Boeing Phantom Works that makes everything else seem small. It has a proposed wingspan of 500 feet and a wing area that is more than an acre. It would, if built, be able to lift 1,400 tons of goods. It is referred to as the Ultra Large Transport Aircraft.
Also in design: the Fozzie, a concept plane by Boeing Phantom Works. It explores the idea of a low-fuel-use plane that uses open-rotor engines mounted on what is called a Pi-tail in the stern of the ship. The wings, being free of engines, have advantages aerodynamically. Despite a fuel-saving concept the plane is designed to go at a speed of 450 mph.
Both would dwarf the previous generation of giants. Driven by the Cold War, the last century saw the U.S. and Soviet Union playing a continual game of oneupmanship with airborne titans.
Beyond the An-225 Cossack, the results for the Russians included the KM Caspian Sea Monster or Ekranoplan. It flew only a few feet above the water and was a familiar Cold War sight flying over the Caspian Sea. It was very long at 348 feet and with a short wingspan of 131 feet, which suited its function. It weighed a hefty 1,080,000 pounds.
The U.S. had, and still has, the C-5 Galaxy. This giant was the world’s largest operating airplane when it was rolled out in 1968, and is still in use by the U.S. Air Force today. It weighs 840,000 pounds and is 247 feet, 10 inches long, with a wingspan of 222 feet, 9 inches. Its purpose: to haul military hardware, including tanks, anywhere in the world.

But nothing outdid the Hughes H-4 Hercules, or Spruce Goose. Made primarily of birch plywood (despite the nickname) it remains the largest plane ever flown. The plane weighed 400,000 pounds, plus the weight of Hughes’ ego. It still has the longest wingspan of any plane ever built, 320 feet. It only flew once and was piloted by Hughes for a mile–44 times farther than the Wright Brothers got.





Giant Panda

Giant Panda
 Giant pandas live in a few mountain ranges in central China, in Sichuan, Shaanxi, and Gansu provinces. They once lived in lowland areas, but farming, forest clearing, and other development now restrict giant pandas to the mountains.
Habitat:
Giant pandas live in broadleaf and coniferous forests with a dense understory of bamboo, at elevations between 5,000 and 10,000 feet. Torrential rains or dense mist throughout the year characterizes these forests, often shrouded in heavy clouds.
Physical Description:
The giant panda, a black-and-white bear, has a body typical of bears. It has black fur on ears, eye patches, muzzle, legs, and shoulders. The rest of the animal's coat is white. Although scientists do not know why these unusual bears are black and white, some speculate that the bold coloring provides effective camouflage into their shade-dappled snowy and rocky surroundings. The panda's thick, wooly coat keeps it warm in the cool forests of its habitat. Giant pandas have large molar teeth and strong jaw muscles for crushing tough bamboo. Many people find these chunky, lumbering animals to be cute, but giant pandas can be as dangerous as any other bear.
Size:
About the size of an American black bear, giant pandas stand between two and three feet tall at the shoulder (on all four legs), and reach four to six feet long. Males are larger than females, weighing up to 250 pounds in the wild. Females rarely reach 220 pounds.
Status:
The giant panda is listed as endangered in the World Conservation Union's (IUCN's) Red List of Threatened Species. There are about 1,600 left in the wild. More than 300 pandas live in zoos and breeding centers around the world, mostly in China.
Life Span:
Scientists aren't sure how long giant pandas live in the wild, but they are sure it's shorter than lifespans in zoos. Chinese scientists have reported zoo pandas as old as 35. The National Zoo's Hsing-Hsing died at age 28 in 1999.
Diet:
A wild giant panda’s diet is almost exclusively (99 percent) bamboo. The balance consists of other grasses and occasional small rodents or musk deer fawns. In zoos, giant pandas eat bamboo, sugar cane, rice gruel, a special high-fiber biscuit, carrots, apples, and sweet potatoes.
Social Structure:
Adult giant pandas are generally solitary, but they do communicate periodically through scent marks, calls, and occasional meetings. Offspring stay with their mothers from one and a half to three years.
The giant panda has lived in bamboo forests for several million years. It is a highly specialized animal, with unique adaptations.
Feeding Adaptions:
Millions of Zoo visitors enjoy watching giant pandas eat. A panda usually eats while sitting upright, in a pose that resembles how humans sit on the floor. This posture leaves the front paws free to grasp bamboo stems with the help of a "pseudo thumb," formed by an elongated and enlarged wrist bone covered with a fleshy pad of skin. The panda also uses its powerful jaws and strong teeth to crush the tough, fibrous bamboo into bits.
A giant panda’s digestive system is more similar to that of a carnivore than an herbivore, and so much of what is eaten is passed as waste. To make up for the inefficient digestion, a panda needs to consume a comparatively large amount of food—from 20 to 40 pounds of bamboo each day—to get all its nutrients. To obtain this much food means that a panda must spend 10 to 16 hours a day foraging and eating. The rest of its time is spent mostly sleeping and resting.
Water:
Wild giant pandas get much of the water they need from bamboo, a grass whose contents are about half water. (New bamboo shoots are about 90 percent water.) But giant pandas need more water than what bamboo alone can provide. So almost every day wild pandas also drink fresh water from rivers and streams that are fed by melting snowfall in high mountain peaks. The temperate forests of central China where giant pandas live receive about 30 to 40 inches of rain and snow a year. Charleston, West Virginia—a city with a similar temperate climate—receives about the same amount of rain and snow: an average of 42.5 inches a year.
Reproduction:
Giant pandas reach breeding maturity between four and eight years of age. They may be reproductive until about age 20. Female pandas ovulate only once a year, in the spring. A short period of two to three days around ovulation is the only time she is able to conceive. Calls and scents draw males and females to each other.
Female giant pandas give birth between 95 and 160 days after mating. Although females may give birth to two young, usually only one survives. Giant panda cubs may stay with their mothers for up to three years before striking out on their own. This means a wild female, at best, can produce young only every other year; in her lifetime, she may successfully raise only five to eight cubs. The giant pandas’ naturally slow breeding rate prevents a population from recovering quickly from illegal hunting, habitat loss, and other human-related causes of mortality.
Development:
At birth, the cub is helpless, and it takes considerable effort on the mother’s part to raise it. A newborn cub weighs three to five ounces and is about the size of a stick of butter. Pink, hairless, and blind, the cub is 1/900th the size of its mother. Except for a marsupial (such as the kangaroo or opossum), a giant panda baby is the smallest mammal newborn relative to its mother's size.
Cubs do not open their eyes until they are six to eight weeks of age and are not mobile until three months. A cub may nurse for eight to nine months. A cub is nutritionally weaned at one year, but not socially weaned for up to two years.
Lifestyle:
A wild panda spends much of its day resting, feeding, and seeking food. Unlike other bears from temperate climates, giant pandas do not hibernate. Until recently, scientists thought giant pandas spent most of their lives alone, with males and females meeting only during the breeding season. Recent studies paint a different picture, in which small groups of pandas share a large territory and sometimes meet outside the breeding season. Much remains to be learned about the secret lives of these elusive animals, and every new discovery helps scientists in their battle to save this species.




Giant spider

Giant spider

A Giant spider is an introductory monster in RuneScape that fights with ranged attacks. They come in a variety of levels, and are weak to crush attacks, so a mace or warhammer will dispatch them quickly, although any melee weapon can be used. They have moderate resistance to ranged and high magic resistance, and will range the player right back if attacked with these styles, so training these skills on them is not advised.
Many new players kill the level 4 giant spiders to train combat because of their low combat level and close location to the starting point in Lumbridge. They primarily attack with ranged.
The level 48 spiders are rarely trained on, and are aggressive. They also use ranged in combat.
The level 57 Giant spiders are fairly accurate and can hit up to 74 LP if you have low defence, so it is recommended that players wear at least full rune armour and bring food (filling the inventory with food is recommended as the spiders drop nothing). Alternatively, members can bring a Bunyip, Saradomin Godsword, Unicorn Stallion, or a full set of Guthans to heal with. The level 57 Giant spiders have 1425 hp and fight with ranged. Unlike their level 4 and 48 cousins, however, they do NOT drop anything, not even charms.
There have been rumors circulating on the Internet of a spider large enough to eat people’s dogs and cats… While it should be obvious that such an animal would not be discovered out of the blue, and the poorly done photoshop job should be a hint, apparently many people have fallen for this. So I figured why not do a debunking and talk about something that I love, spiders.
To start with the photo, there are VERY clear signs that it was photoshopped, and poorly at that. And even if the photoshop had resulted in a masterpiece of deception, the image simply doesn’t make sense; the shape, body type, location, behavior, none of it.
More interesting than any of that though, is that there are real limits to how large spiders can actually get, based primarily on the (relative) ineffectiveness of their “lungs”, among other factors. They simply can’t grow past a certain size in relation to the oxygen content in the atmosphere, or they wouldn’t survive.
Most spiders possess what are called “book lungs“, which are completely unrelated to what we normally call lungs, and developed independently. And from fossil evidence, we can determine that these structures have remained more or less unchanged throughout the past 400 million years because of how effective they are. There are downsides/limits to them though, with relation to lungs as we know them. As body size increases in relation to gas molecule size, they become less effective. This means that as animals with these structures get bigger they become less and less effective at “breathing”, which places limits on their maximum size.

Other limits to their maximum body size include a decreasing effectiveness and durability of their exoskeleton and muscular system, as they get larger they generally need to become thicker to compensate for this (especially highly-mobile spiders), tarantulas are a good example of this.
The two largest spiders alive in the world today are both approaching the limits of maximum spider size, in the current atmosphere anyways, perhaps not in the distant past. They are the foot long Goliath bird-eater tarantula, and the Giant Huntsman in Vietnam. Neither of these come close to approaching the size of the “Angolan Witch Spider”.