I learned about something called axial precession in astronomy class several years ago, which is the idea that as something rotates along its axis, it will slowly trace out a cone if the weight of the object isn't equally distributed. In the case of Earth, Earth isn't a perfect sphere as many of us may think it is -- it actually bulges out in the middle enough for it to allow this phenomenon to occur. At the time, all I really took from this concept was how fascinating it is for the north axial pole to move 1° every 72 years from where it is now, and complete one full cycle every 26 000 years. However, I never managed to understand how this concept could fit in to my understanding of why ice ages[1] occur, and why they too follow a specific ...

Their name and shape!

Ostraciidae is a family of squared, bony fish closely related to the pufferfishes and filefishes. Members of this family occur in a variety of different colors (e.g. right - Hawaiian Blue Boxfish, Ostracion meleagris and the Yellow Boxfish, Ostracion cubicus), and are notable for the hexagonal or "honeycomb" patterns on their skin.

Boxfish swim in a rowing manner. Their hexagonal plate-like scales are fused together into a solid, triangular or box-like carapace, from which the fins, tail, eyes and mouth protrude. Because of these heavy armoured scales, Ostraciidae are limited to slow movements, but few other fish are able to eat the adults.

Some boxfish also secrete poisons from their skin into the surrounding water, fu ...

Well, obviously it's white, but take a look at its bill!

The attractive 7.5-inch-long bill is possessed by both male and female toucans. Interestingly, they use them during a mating ritual, pitching fruit to one another, but has very limited use as an excavation tool. Toucans make their nests in tree hollows found in rain forest regions of Southern Mexico, Central and South America, and the Caribbean region to which they are native.

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The brownish staining of a child's tooth enamel is due to excessive ingestion of fluoride. Fluoride is a mineral compound that is useful in preventing dental caries. It is thought to work by strengthening the mineral composition of tooth enamel making it more resistant to acid attacks. It may also reduce the acid-producing ability of microorganisms in dental plaque. The water supply may naturally provide fluoride, or it may be added. Mild fluorosis causes white mottling of the teeth; severe cases show brown staining and usually occur in areas where the level of fluoride in the water is many times greater than the recommended level of 0.7 to 1.2 parts per million. ...

Hemocyanins are proteins that transport oxygen throughout the bodies of some invertebrate animals. These metalloproteins contain two copper atoms that reversibly bind a single oxygen molecule (O2). They are second only to hemoglobin in frequency of use as an oxygen transport molecule. Unlike the hemoglobin in red blood cells found in vertebrates, hemocyanins are not bound to blood cells but are instead suspended directly in the hemolymph. Oxygenation causes a color change between the colorless Cu(I) deoxygenated form and the blue Cu(II) oxygenated form. ...

Researchers studying a group of wedge-capped capuchin monkeys that live in tropical forests of central Venezuela have discovered that the monkeys protect themselves against the annual merciless onslaught of mosquitoes exactly as humans do: by rubbing themselves with mosquito repellent.

But while humans may reach desperately for spritzers or bottles or laughably overhyped ''protective'' skin-so-softeners, the capuchins have learned to poke around in tree bark or termite mounds to extract a wriggling specimen of Orthoporus dorsovittatus, a millipede rich with powerful defensive chemicals called benzoquinones.

The capuchin monkey will then proceed to anoint itself head to foot with the repellent secretions by massaging the four-inch-long millipe ...

Are you superstitious of the number 13? Some people are so extreme, it's an actual phobia called triskaidekaphobia. Weird.