While reliable information on this question is fairly hard to come by, there have been a few reliably substantiated cases of dogs living for almost 30 years.

The oldest dog that has been somewhat reliably documented was an Australian cattle-dog named Bluey. He is reported to have lived from June 7, 1910 to November 14, 1939 (29 years, 5 months and 7 days). Bluey was owned by Les and Esma Hall of Rochester, Victoria, Australia.

In September, 2008 another dog was reported to have died at over 29 years old. Bella, a Labrador mix was owned by David Richardson of Derbyshire, England. The Guinness Book of World Records reports the oldest dog (with reliable documentation) to be Butch, a 28-year old Beagle in America who died in 2003.  See the list of oldest dogs on record.

Bramble, the Labrador pictured above was reliably recorded to have lived over 27 years and died in Somerset, England in 2003. He currently has the position as the second oldest dog on record.

Sources: The World’s Oldest Dog Dies and Vegetable-Eating Dog Lives to Ripe Old Age of 27.

While the American grizzly bear is fearsome and cool to look at, the polar bear is generally considered the largest bear in the world. Its average weight is between 900 and 1500 pounds. The brown bear, averaging 500 to 900 pounds a close second.

The biggest polar bear ever recorded was a male shot in Kotzebue Sound in Alaska in 1960 weighing an amazing 2,210 pounds (1002 kilograms) and was 11 feet 11 inches in height. Source: Wood, G.L. (1981). The Guinness Book of Animal Records. pp. 240.

There has been some debate on this, depending on how you define an animal’s size. The Bumblebee Bat (Craseonycteris thonglongyai) is definitely the world’s smallest species of bat. It is about 30mm in length and weighs about 2 grams (less than an American penny). It is the only known species in its genus and is found in a tiny region of western Thailand, in the Sai Yok National Park, Kanchanaburi Province.

One of the more interesting notes is that the Bumblebee Bat was virtually unknown until 1974 when it was discovered by Kitti Thonglongya, a biologist in Thailand. Their habitat has been highly affected by deforestation and unsustainable levels of teak logging. In 1982, the Royal Forest Department of the Thailand Government only found 160 of them living in 3 caves, despite extensive surveys. Bumblebee bats are now considered one of the twelve most endangered species on the planet.

The other mammal in competition for the title of the “world’s smallest” is the Etruscan Pygmy Shrew (Suncus etruscus). This shrew weighs less than the Bumblebee Bat but the bat’s skull is shorter. [Wikipedia] The smallest mature specimens of this shrew are thought to weigh about 1.3 grams and measure 36 mm long. This small mammal is 60 mm from the tip of the nose to the base of the tail. This shrew has a lifespan of about 15 months and lives the forests and brush areas between Southern Asia and Southern Europe.

Sources: Portland State University,  Experience Festival.

The largest spider in the world is a tarantula called the Goliath Birdeater. An adult can weigh over four ounces (about the size of a large mouse) and has a leg span of up to 12 inches. The spider was given its unique name by Victorian explorers who witnessed one eating a hummingbird although birds are not typically part of its diet. They survive mostly on small insects and meal worms but will occasionally eat small rodents such as mice, shrews and moles.

Wild goliath birdeaters are a deep burrowing species, found commonly in marshy or swampy areas. Goliath birdeaters usually live in burrows in the ground that they have either dug themselves or have been previously abandoned by rodents or other similar creatures.

The goliath birdeater is fairly harmless to humans, as are most species of tarantulas. Like all tarantulas, it has fangs large enough to break the skin of a human and they do carry venom in their fangs and have been known to bite humans when threatened, but the venom is relatively harmless and its effects are comparable to those of a wasp’s sting. Tarantulas generally bite humans only in self-defense, and these bites do not always result in envenomation. The goliath birdeater has poor eyesight and mainly relies on vibrations in the ground that they can sense from their burrows.

Source: Wikipedia.

Mimosa pudica (also known as the “sensitive plant” or “Tickle Me plant”) is well known for its rapid leaf movement. In the evening the leaflets will fold together and the whole leaf droops downward. It then re-opens at sunrise. This type of movement is called nyctinastic movement. The leaves also close up under various other stimuli, such as touching, warming, or shaking (hence the name, Tickle Me plant).

The stimulus can also be transmitted to neighboring leaves. The scientific term for these are seismonastic movements. The movement is caused by “a rapid loss of pressure in strategically situated cells that cause the leaves to droop right before one’s eyes”. [Wikipedia] This characteristic is quite common within the Mimosaceae family. Gradual loss of pressure can also cause the plant to close its fronds as is sometimes the case when it is exposed to a strong wind, rain or sunlight.

Why the plant’s leaves close up when exposed to these external stimuli is most likely an evolutionary response. As the leaves fold down, sharp thorns are exposed and would make the plant less tasty for herbivore animals that might want to eat them.

This is a very generic question, but one that actually gets asked quite frequently.  Of course, the short answer is that snakes have a varied diet, depending on factors such as their species, size, age, geographic locale, etc. A fairly accurate answer for what most snakes eat might be: insects, worms, lizards, birds, small amphibians such as frogs and salamanders, and small mammals such as rats, mice and voles. But even this answer could vary depending on a location. A common garter snake that lives in a wooded area near a pond will likely eat more frogs than the garter snake found in your backyard which might live entirely on insects and the occasional mouse.

The more interesting answer is to the question: what do some of the larger more exotic snakes eat? Some snakes primarily eat other snakes (the bandy-bandy of Australia). Some snakes eat mostly the eggs of other animals (see image above). And some of the larger snakes such as pythons and other constrictors will eat small mammals when young and begin to eat larger animals such as pigs, monkeys and deer as they mature.

This is a bit of a humorous post as this question has made the rounds on the Internet for the last several years. The short answer is: goldfish are egg-layers and as such, they’re never considered pregnant. A female goldfish carrying eggs is said to be “ripe” but no ichthyologist would say she’s pregnant. You may have stumbled upon posts or trivia lists saying that a pregnant goldfish is called a twit, twat, twerp or whatever. They’re not.

Some magnets are natural (lodestone and magnetite are naturally occurring), and some magnets are man-made. The magnets made in the laboratory are usually made of a mixture of iron, cobalt, nickel and other elements. The substances are magnetized by a couple of different methods. You could move a permanent magnet in one direction across the material to magnetize it. You could produce an electric current through coils around the substance to magnetize it. And some magnets can be made from a chemical reaction (ie., certain elements will become magnetic when reacting with oxygen).

Wikipedia gives a great description of exactly what a magnet is and how it works. Some of which I’ll summarize here. [source: Wikipedia] A magnet is a material or object that produces a magnetic field. This magnetic field is invisible and causes the most notable property of a magnet: a force that pulls on nearby magnetic materials, or attracts or repels other magnets. The structure of the invisible magnetic field of a magnet is made visible by the pattern formed when iron filings are scattered around the magnet, as in the graphic above.

A permanent magnet (also called a hard magnet) is one that stays magnetized. An example is the common magnets you put on a refrigerator door. Permanent magnets occur naturally in some rocks, particularly lodestone, but are now more commonly manufactured. A soft magnet (also called an impermanent magnet) is one that will gradually lose its magnetization. Soft magnetic materials are often used in electromagnets to enhance (often hundreds or thousands of times) the magnetic field of a wire that carries an electric current and is wrapped around the magnet; the field of the soft magnet increases with the current.

The Bubonic plague is a disease of the lymphatic system caused from the bite of an infected flea. The fleas are often found on rodents and seek live hosts (such as humans) when their rodent hosts die. Once established, bacteria rapidly spread to the lymph nodes and multiply. Yersinia pestis can resist phagocytosis and even reproduce inside phagocytes and kill them. As the disease progresses, the lymph nodes can hemorrhage and become necrotic. Bubonic plague can progress to lethal septicemic plague in some cases. Bubonic Plague kills about 50% of infected patients within one week.

What most people reading this were probably searching for is actually the Black Death, a specific incident of a Bubonic Plague epidemic that happened in Europe in the 1340s. At the time of the breakout, the world’s population is estimated to have been about 450 million. The Black Death killed about 75 million, or roughly one sixth of the population on Earth. Compare those figures to today’s population and that would be the equivalent of over 1 Billion people dying from the breakout.

The name “Black Death” comes from the fact that the disease causes symptoms like spots on the skin that are red at first and then turn black. Other symptoms include heavy breathing, continuous blood vomiting, aching limbs and terrible pain. The pain is usually caused by the actual decaying, or decomposing of the skin while the infected person is still alive.

No one person is considered to have discovered Mars. As it is very bright in the night sky, it has been visible since the first humans gazed up to the heavens. What we do know is that it was named after the Roman god of war- presumably because of its red color which may have reminded our ancestors of blood.

1659: Christian Huygens discovered the dark spot located in the boundary between the northern lowlands and southern highlands of the planet. It was later called the Syrtis Major.

1877: Astronomer Giovanni Schiaparelli discovered what he believed to be several lines crossing one another. He claimed they were water canals made by intelligent creatures.

1877: Astronomer Asaph Hall spotted the two moons and named them Phobos and Deimos (fear and panic). He named them after the mythical horses that pulled the chariot of the Roman god, Mars.

1971: Mariner 9 returned images of Martian volcanoes and canyons. It discovered Olympus Mons, a massive volcano towering over 15 miles above the surface. Mariner 9 also found evidence that water once flowed on Mars. There were no sightings of Schiaparelli’s famous canals.

1975: Viking I and II spacecraft landed on Mars to study its surface. They analyzed the rocks and soil of the planet while providing us with information about its atmosphere and weather patterns.

Source: Wikipedia and the University Corporation for Atmospheric Research.