Ask The Science Experts

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.

Posted by mo for the best selling science toys at Atomic Elephant Toy.

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. Posted for the science and educational best selling toys of 2008.

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. Posted by the science guy for best selling science toys at Atomic Elephant Toy.

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.

Posted by the science guy for the best selling science toys of 2008.

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.

Posted by the science guy for the best selling science toys of 2008 at Atomic Elephant Toy.

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.

Posted by the Triop Guy for Triassic Triops make great fishy gifts!

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.

Posted by The Science Guy for the best selling science toys of 2008.