7 Sea otters hold hands while sleeping, eating, and resting so they don’t drift away from each other.

Otters are marine mammals that can be found on the Northern Pacific Ocean coasts. They are the largest member of the weasel family. In the whole of the animal kingdom, they have the densest fur ranging from 250,000 to one million hairs per square inch. Otters are known to hold hands in groups, called rafts, while they eat, sleep, and rest to prevent families losing each other. Also, sea otters use sea plants that grow from the ocean floor to wrapping themselves in which also helps prevent them from drifting away.(source)

8 The human lungs contain approximately 2,400 kilometers of airways.

The lungs are the respiratory organs. Humans have two lungs, a left lung, and a right lung. The right lungs have three lobes while the left lung consists of only two lobes. Together the lungs contain approximately 2,400 kilometers (1,500 mi) of airways and 300 to 500 million alveoli (air sacs). The total surface area of lungs varies from 50 to 75 square meters (540 to 810 sq ft), roughly the same area as one side of a tennis court. Moreover, if all the capillaries that surround the alveoli were unwound and laid end to end, they would extend for about 992 kilometers.(source)

9 A vegetarian who eats meat occasionally is called a “Flexitarian”.

“Flexitarian” is used to describe a diet or a person who eats “mostly” vegetarian but occasionally includes meat in the diet. A flexitarian or a semi-vegetarian is not a vegetarian. Also, flexitarianism differs from pescetarianism. Pescetarianism is a diet that includes fish only, along with vegetarian foods. This means that a pescatarian who only occasionally eats fish is a flexitarian, but a flexitarian is not necessarily a pescatarian if they also include chicken, pork, beef, and other meats in their diets.(source)

10 Cat urine glows under black light.

A black light (ultraviolet, infrared) can be used to detect body fluids. Cat urine, in particular, glows very brightly under ultraviolet light. Cat urine glows under a black light primarily because it contains the element phosphorus. In the presence of oxygen, with or without black light, phosphorus glows yellowish-green, but the black light imparts additional energy that makes the chemiluminescence easier to see. Urine also contains broken-down blood proteins that glow under a black light.(source)

11 A kangaroo can be almost permanently pregnant by pausing her pregnancy in times of drought. It’s called “diapause”. 

Kangaroos, who are prolific breeders in good times, have developed a special mechanism to help them cope during harsh times. They can hit ‘pause’ on their pregnancy. Female kangaroos can be almost permanently pregnant, pausing the growth of their baby mid-way through development when conditions aren’t right. and then nursing multiple joeys when times are good.(source)

12 There are 118 ridges on the edge of a dime.

The rims on U.S. dimes, quarters, half-dollars, and some dollar coins are called “reeded edges”. Reeded edges served a two-fold security purpose for silver coins. One, they added an additional, intricate element to the coins which makes it difficult to counterfeit. Two, they prevented theft. Before reeded edges, coin clipping was a quick way to make profits. Clippers, working carefully, would shave off a tiny amount of metal all the way around the rims of coins, but not so much as to make them noticeably lighter or smaller. Reeded edges foiled this scheme since a shaved edge would be immediately obvious and alert anyone. Nickels and pennies didn’t have reeded edges because they are mainly composed of inexpensive metals. With the passage of the Coinage Act of 1965, the dime’s silver content was removed. Dimes from 1965 to the present are composed of outer layers of 75 percent copper and 25 percent nickel, bonded to a pure copper core.

The number of reeded edges in coins are:. dimes 118, quarters 119, half-dollars 150, dollars 198.(source)