Science

No, because even the largest carnivorous plants are only big enough to digest something the size of a frog, and the digestive enzymes they secrete are comparatively weak. Very rarely, a rat or bird has been found drowned in the liquid contained in the bottle-like appendages that hang from the vines of Nepenthes rajah, a … Read more

It may be that the rich orange smell of the fruit, which folklore has long rumored to be an insect repellent, scares them off, or it may be that the latex-rich leaves gum up the mouth parts of insects, eventually discouraging others. You could try leaving the fruit around your house, or experiment with planting … Read more

While not poisonous, large quantities of rhubarb, stems or leaves, offer possible risks, and the stems may be as bad as the leaves for susceptible people. To complicate things, some rhubarb chemicals can have positive or negative effects. In cell cultures using an extract of the entire plant, studies found some antimutagenic effects, depending on … Read more

With patience, a rose can be grown from a seed, and indeed all the Peace roses of today are descended from a plant grown in 1939 from a single seed nurtured by Francis Meilland, the hybridizer. But a random seed from a Peace rose or any hybrid would be unlikely to produce a plant like … Read more

Yes, there are such plants, called halophytes. Some are natural species that grow well when the water they get has a high salt content. Others are species that scientists are tailoring for the purpose by selective breeding or crossbreeding for salt-tolerance genes. Halophytes include grasses, shrubs, and trees. Some are edible crops suitable for areas … Read more

What you heard about is mycorrhizae, complexes formed by beneficial fungi and plant roots. There are many different ones, and particular plant species form relationships with particular species of fungi. There are three basic types, depending on where the complex is formed: endomycorrhizae, inside the root hair; ectomycorrhizae, outside the root hair, and endoectomycorrhizae, both … Read more

No, but certain species among the hundreds or thousands of known bamboos die off all at once after their single episode of flowering. That can create problems for gardeners who cultivate a particular ornamental type. More seriously, a mass die-off of a bamboo species in the phenomenon called gregarious flowering can endanger a species, like … Read more

The timing of leaf loss varies with species, site, and season. Day length and temperature are the two triggers for color change and leaf loss. The timing is usually species specific but is also related to site conditions. For example, a fairly dry midsummer to fall in the Northeast can mean that some trees drop … Read more

Evergreen trees do not keep their leaves indefinitely, but rather may grow new ones before the old ones fall, or keep some and drop others over a period of time. As any southern gardener can tell you, some broadleaf evergreens, like Magnolia grandiflora, drop their heavy leaves in a staggered cycle over the course of … Read more

Trees grow vertically because of two things: gravity and light. Geotropism, in which microscopic particles in plant cells react to gravity, tends to make the roots grow straight down, which means that the stems grow straight up. Phototropism tends to make plants grow vertically as well, following the direction from which light comes. Phototropism was … Read more

Let us assume that you get the biggest plain, enriched bagel analyzed by the U.S. Department of Agriculture, 4 inches in diameter, weighing 110 grams, about 3.8 ounces. The ingredients flour, water, salt, yeast, and malt, but no sugar, if it is a classic bagel —are boiled and then baked. They add up to 302.5 … Read more

It is really a physics problem involving the interaction of water with a carbohydrate, and the process differs from food to food. When you have a solid food that you want to be able to cook faster, such as rice, you hydrate it, then dehydrate it under controlled conditions, adjusting the chemistry and physics of … Read more

Asiatic ginseng, Panax schinseng, and the American wild ginseng, Panax quinquefolius, are closely related and similar in both appearance and effects. Siberian ginseng includes species of a different family, the Eleutherococcus family, which is not real ginseng. There is not a big medicinal difference between the two “real” ginsengs. Each has a slightly different composition … Read more

Fish contains quite a bit of a substance that gives rise to two chemicals that make the rotten-fish smell, while red meat has hardly any. The chemicals are trimethy lamine and dimethylamine, both derived from trimethylamine oxide, which is particularly common in the flesh of fin fish, especially cold-water, surface-dwelling ocean fish like the cod. … Read more

Like all vegetables and fruits, tomatoes differ somewhat in nutritional value from variety to variety, and even from season to season. For example, the U.S. Department of Agriculture lists different average nutrient contents for tomatoes harvested from November to May and for those from June to October. Many food values are comparable for red and … Read more

Temperature changes can either delay or hasten the ripening of bananas. The banana is a tropical fruit, adapted to ripen most quickly at a certain stage of its development and at a particular temperature and humidity. Bananas continue to ripen after they are harvested, with more and more of their starches converted into sugars by … Read more

The best-known method relies on the amount of a pepper extract mixed with water that a panel of tasters need to sense the heat. Invented in 1912 by Wilbur L. Scoville, a pharmacologist, the rating is given in Scoville units. The sample is dried and mixed with alcohol; then sugar water is added. The tasters … Read more

The skin that forms on the surface of milk when it is heated is a complex of casein, or milk protein, and calcium, and results from evaporation of water at the surface of the heated liquid and the concentration and coagulation of protein there. Skimming the skin off removes significant amounts of nutrients. Skin formation … Read more

Wine that is simmered for a long time in a stew would probably retain only a small fraction of its alcohol, but other dishes, like briefly flambeed crepes Grand Marnier or a soup with sherry added at the last minute, would probably still have enough to be of concern to those who want to avoid … Read more

Yeasts are simple one-celled plants, members of the large Ascomycetes family of funguses. The powder or cake sold for baking is billions of cells of one of 160 or so useful funguses that are called yeast. Commercial baker’s yeast is a pure, selected strain of Saccharomycee cerevisiae. It is a “tame” yeast, raised in factories … Read more

The holes in Swiss Cheese are made by sizable bubbles of gas produced by a special kind of bacterium in the cheese-ripening process. There are three basic steps in producing most kinds of cheese: making curds from milk, concentrating the curds, and ripening the curds. First, hungry bacteria, pure cultures of streptococci and lactobacilli, feed … Read more

What weather reports call black ice is not black at all; it just looks that way because it is transparent and whatever color the road’s surface is shows through. Whether ice on the road is visible depends on how it is formed. Rime ice, which is visible, forms when droplets of freezing drizzle adhere to … Read more

Some scientists think it is possible that volcanic activity might be at least partly responsible for the periodic weather phenomenon called El Nino. This theory was inspired in part by the discovery in 1993 of the largest known cluster of volcanoes, covering an area the size of New York State. The area in question is … Read more

Humidity is one of several atmospheric factors affecting the propagation of sound. Heavy, muggy air actually carries sound better. Bone-dry air greatly attenuates sound. But humidity is not as prominent a factor in affecting low-frequency sound as the bending of sound rays (or sound waves going in the same direction) by wind and the temperature … Read more

Considering the physical forces on precipitation as it falls, drops would probably be more properly described as shaped like a hamburger bun, flat on the bottom but rounded on the top. The shape of the drop as it comes down is ultimately a product of the interaction between the force of gravity acting downward and … Read more

Summertime conditions in the Rockies constitute a recipe for thunderstorms. The ingredients are strong sunshine coming at a direct angle to warm the land below, sharp differences in temperature between air warmed by the mountains and cooler air over adjacent plains, and enough water in the air. Thunderstorms owe their existence to thermals, or localized … Read more

A rain gauge shaped like a megaphone is not the standard shape meteorologists use, but it should work if it has the correct ratios between the cross-sectional area at the top and the part of the gauge that actually collects and measures the water. If this gauge was a straight-sided cylinder that did not narrow … Read more

Cloud-seeding experiments and government programs continue, but in this country at least, they are not regarded as a panacea for drought. The programs are usually subject to strict controls. Some thirty-two states have enacted laws regulating who can practice cloud seeding. Cloud seeding dates from experiments in 1946 at the General Electric Laboratories in Schenectady, … Read more

Contrails, or condensation trails, are clouds of ice crystals formed when hot, moist air from aircraft engines mixes with cold, drier air in the upper atmosphere. Contrails are similar to cirrus clouds, naturally occurring clouds found at altitudes around 20,000 feet. Portions of the upper atmosphere are too dry to produce condensation, so aircraft flying … Read more

When the National Weather Service forecasters use the term probability of precipitation, they mean that in ten instances of weather patterns similar to the one they are looking at, it rained five times. The service keeps cumulative records, and the probability forecast is a statistic based on what has happened. For example, if a cold … Read more

A cloud’s color depends chiefly on the cloud’s relationship to the light of the Sun. In some cases, it depends on the color of the surrounding sky. If a cloud covers the whole visible area of the sky, the depth of the cloud determines the color of the cloud; the deeper it is, the darker … Read more

The chief practical reason for setting the clock an hour later for a certain period of the year, so that the Sun sets later by the clock, is not to “save” daylight, but to make daylight hours coincide more closely with the time when most people use energy. A major effect of daylight saving time … Read more

It would have exactly twelve hours of daylight if this were an airless world with no atmosphere. However, Earth’s atmosphere acts like a lens and bends, or refracts, the Sun’s light above the horizon. When you see the disk of the Sun resting on the horizon at sunset, you are looking not at the Sun … Read more

Physicists say it is not so much that big stones work their way up as it is that smaller particles work their way down. Physicists have long known that in a mix of large and small objects, the large ones tend to end up higher while the small ones end up lower. This holds true … Read more

There are three basic channel patterns for a river: straight, meandering, or braided. Depending on such factors as terrain, soil, and water volume, different stretches of a river may show different patterns, and channels may shift over time. There is no fixed rule for the evolution of a river’s channel, but one typical progression is … Read more

The freezing temperature of water drops about 1 degree for every 75 of the units of pressure called atmospheres, but the change is small compared with the difference even one atmosphere of pressure makes in raising the boiling point. (One atmosphere is equal to 14.69 pounds per square inch.) Why deep sea water does not … Read more

One important reason is that the complex ecology of the prairie environment is formed by a cycle of fires and regrowth of a succession of fire-tolerant plants, and trees do not survive the periodic fires. The other limiting factor is a dry climate, affecting trees more than grassland plants, which hoard water. The fires sustained … Read more

Questions of pollution aside, the answer, oceanographers say, is that cold northern waters tend to teem with great concentrations of tiny plants and animals (phytoplankton and zooplankton), while southern waters are (in terms of numbers of individual organisms) empty deserts, with a few species-rich oases, such as coral reefs and waters fed nutrients by river … Read more

Rising sea levels worldwide following the last Ice Age are a more likely explanation for a great flood about 7,500 years ago, or 5500 B.C., that suddenly inundated areas around the Black Sea. Some scientists suggest it could have been the basis for flood stories in both the Hebrew Bible and the Babylonian epic of … Read more

Flood stage and crest have fairly simple definitions. The flood stage is the height of a river above which damage begins to occur, typically because the river begins to overflow its banks. The crest is the highest level that a river reaches. Prediction is a more complex matter, involving thousands of readings of river stages … Read more

In the 1960s, an Australian graduate student found rocks from an ancient aboriginal campfire, perhaps 30,000 years old, that were lying in place, magnetized in the opposite direction from the present-day orientation of the earth’s magnetic field. The student suggested to his amazed professor that this was evidence of a shift in the magnetic field … Read more

If there were a sudden overnight flip of the Earth’s magnetic field, scouts might be in trouble with their compasses, but most electrical appliances would not be affected. The compass needle is just a little magnet that lines up with the magnetic field lines of Earth; these imaginary lines converge on a spot near Greenland. … Read more

What the United States Census Bureau calls the geographic center of area is the point on which the surface of a geographical entity would balance if the surface were a plane of uniform weight per unit of area. For the United States, that point has been in Butte County, South Dakota, on the state’s western … Read more

The current plans involve bringing along a rocket that could be launched from Mars into a low orbit, where it would meet another craft that would return to Earth. The vehicle that returns to Earth would carry some kind of Earth-entry vehicle, like a capsule or shuttle plane. To make the return cheaper by bringing … Read more

Yes, a gun fired in space or on a space station or rocket ship should work as well as it would on Earth or possibly even better. The laws of physics still apply in space. The path of the bullet should be fairly straight, as gravity is greatly reduced, though not entirely absent. There may … Read more

There is growing evidence that exercise can help astronauts recover from muscle and bone losses and limit such losses. In the near absence of gravity, bone mass decreases in the load-bearing regions of the skeleton, and muscles shrink when not used. But Michael Foale, who was on the Russian space station Mir for four and … Read more

It has largely to do with the fidelity of the microphones, not the quality of space-to-ground communications systems. The astronauts wear wireless mikes that are as light and unobtrusive as NASA can make them. An FM signal goes from the astronaut to a communications device, then is radioed through a satellite system to the ground. … Read more

Shortly after the shuttle clears the launching tower, the software of its automated guidance, navigation, and control system initiates a roll command to line it up on the desired course and heading. The roll program tells the engine nozzles how much to gimbal, or swivel, to aim the shuttle properly. It goes straight up for … Read more

Parents have supposedly explained human reproduction to children in terms of the birds and the bees. If birds were really used to make this explanation, it would be widely believed that fertilization occurs after the briefest period of proximity of the waste elimination organs. Most birds do not have external sex organs. The transfer of … Read more

Smaller eagles have occasionally been “domesticated” by falconers and were traditionally reserved for the hunting pleasure of medieval kings. The American bald eagle, which has a wingspan of up to 7 feet and would therefore require a very large falconer, has been reliably reported to have lived for 30 years and 5 months in captivity … Read more

The assumption that a bird’s tail functions only as a horizontal surface is erroneous. A bird also can twist its tail from left to right and downward, so it acts almost as a braking system that allows it to bank into turns. Some birds are better at this than others. Some hawks in the group … Read more

The pinkness of flamingos is determined by food, but not by pink shellfish. The factors in the flamingo diet that ensure pinkness are carotenoid pigments, which are found in plankton, diatoms, and blue-green algae that the birds strain out of the muck in which they feed. The birds process yellow carotene into a red compound, … Read more

The winner, wings down, is the peregrine falcon, Falco peregrinus, which may also be the fastest animal of any kind on earth. Estimates of its top speed when diving start around 200 miles per hour, and some authorities put it considerably higher, perhaps 275 m.p.h. Its top horizontal speed is 60 m.p.h. or more. The … Read more

Short of exterminating all the crows in town, there is not much chance of getting rid of them. Driving out one family simply opens a place for another young male to move in. One possible way is to make things less attractive, but what attracts crows is the same thing that makes gardens attractive to … Read more

Like mammals, birds take in air and extract oxygen from it to supply body tissues, while fish respiration depends on getting the oxygen dissolved in water through organs called gills. But bird respiration is significantly different from that of mammals. In the very efficient avian system, the lungs are small, taking up just 2 percent … Read more

Yes, and though it is highly variable from species to species, research is leading to a higher estimation of birds’ smelling abilities. Sensitivity to odors varies among orders of birds with the size of the olfactory bulb in the brain relative to that of the cerebrum. The bulb tends to be small, but it is … Read more

Probably, based on structural features and fossil evidence, though some scientists studying DNA evidence suspect otherwise. There are studies, primarily of mitochondrial genes, suggesting that guinea pigs might not be rodents, but might belong to their own separate order. (Mitochondrial DNA is carried by the structures in cells that act as cellular power plants. It … Read more

There is no special equipment, just a highly developed ability to imitate. The ability to imitate a species’ own song is present in all songbirds. Some birds, like woodpeckers or chickens, do not actually learn songs. But of the birds that do, some learn a little and some learn a lot. Among the star imitators … Read more

Yes, in some cases. Kidney transplants were pioneered by the School of Veterinary Medicine at the University of California at Davis and are now performed at some other veterinary colleges around the country. They can cost $3,000 or more. There are no other transplant programs for dogs or cats, though there was initial research on … Read more

Brain size is not generally seen as a reflection of intelligence in dogs or in other species. That is evident if you compare other species with different brain sizes — for example, elephants and people: People are far more intelligent despite the huge disparity in physical size. Intelligence has more to do with the development … Read more

“Sense” in its physical meaning is the key word. Many case reports cite instances of animals’ behaving in strange ways before natural phenomena, but there is little scientific data. Domestic animals, dogs and cats in particular, have hearing and other sensory capacities that are greater than those of people. Their hearing is more sensitive and … Read more

There are two approaches. One is avoiding the buildup of the charge; the other is discharging it so you cannot shock the cat or yourself. The cat also builds up a charge, but because of its smaller size, most of the flow is from you to the cat. In friction between any two materials with … Read more

Whiskers give cats important sensory information and also have a role in communication between cats. They are far more important to a cat than a dog’s whiskers are to a dog, and they should never be trimmed, as they tell a cat whether it can squeeze through a narrow passage, for example. Technically called vibrissae, … Read more

Yes, allergies are common in cats and dogs. They arise by similar mechanisms and can cause similar symptoms, though skin eruptions are more common in cats and dogs than sneezing or digestive distress. Treatments may be similar, too. In an allergy, the animal’s immune system is hypersensitive to some substances it encounters, called allergens. For … Read more

It is probably more evolutionary than it is anything physiological, and is possibly related to hunting techniques. It is not usually seen in farm cats, who have to work for a living. Their predatory behavior involves sitting beside a mouse hole for hours, then pouncing. Instead, the mad dash is often seen among well-fed, secure, … Read more

One recent estimate is 10 million to 13 million living species. A 1988 study said only about 1.5 million species then had scientific names, though far more certainly exist. The study pointed out that “total” figures are not actual counts, but theoretical reckonings based on things like the number of species that make up typical … Read more

Although it can be difficult to know with certainty, there are clues in the shape and size of bony landmarks on the skull. You usually can’t sex other bones reliably, except for the pelvis. With the skull, what scientists look for is the difference between what is called robust morphology, meaning typically heavier, larger shapes … Read more

They are cousins but belong to different families. All are members of the cetacean order, which includes whales, and all belong to the suborder odontoceti, literally meaning toothed whales. The thirty-two species of seagoing dolphins (members of the family Delphinadae) are perhaps most easily distinguished from the six species of porpoises (members of the family … Read more

In some whale species, a third whale may have a role in courtship, but it is now thought to involve competition, not assistance. The California gray whale, Eichrichtius robtistus, has many more males than females. During courting, two males will often follow one female, and the trio will stay together right up to the moment … Read more

Yes, some fish are simultaneously hermaphroditic, possessing the reproductive equipment of both sexes at one time; a few can fertilize their own eggs. In some species, called sequential hermaphrodites, an individual can change from male to female, from female to male, or back and forth. Some fish species are entirely female and reproduce by cloning … Read more

The several species of oceanic flying fish seem to take flight either when they are alarmed or when they are attracted by a light shining in the night. Most flying fishes belong to the family Exocoetidae and live in the surface waters of all tropical oceans. They are able to leap out of the water … Read more

There is no special name for the sticky substance, but scientists do know it is secreted by mucous glands at the moment the frog’s tongue hits the prey. Otherwise it would stick the frog’s mouth together. The tongue of a frog, which is hinged at the front of the mouth, not the back, can be … Read more

There are two groups of lizards commonly called chameleons, and they change colors in different ways. True chameleons belong to an Old World family called Chamaeleontidae, with two genuses and about eight-five species. They have a variety of colorations, which they can change, to a greater or lesser extent, by concentrating or spreading out the … Read more

Rattlesnakes are good swimmers, though they are not in a class with species that spend all or most of their lives in water or even with the familiar garter snake. From anecdotal accounts, we know that rattlesnakes will swim readily enough when their travels in search of food, mates, or refuge require them to cross … Read more

The turtle lives ‘twixt plated decks Which practically conceal its sex. I think it clever of the turtle In such a fix to be do fertile. The poet Ogden Nash was right about the turtle’s external ambiguity and fertility. Turtles are not only enthusiastic breeders, they also have external sexual characteristics that often make it … Read more

Most snakes have specialized body structures that let them swallow things that are larger than their heads or necks. First, a snake’s skin is very elastic. Even more important is the fact that the snake’s jaws are made up of four elements, not two, and they are only loosely attached with ligaments that can stretch … Read more

As you suspect, the chirping noise a chipmunk makes probably has less to do with foraging, as the familiar fat-cheeked eastern chipmunk (Tamias stratus) can easily collect and store a life-time supply of food in a single season, than with protecting territory and warning off interlopers. Chipmunks have a variety of vocal sounds, not all … Read more

The subject is a confusing one because of the rather inexact use of terms in most post-Roman cultures. Especially large or poisonous snakes are commonly called serpents, and biblical tradition calls the shape Satan assumed to tempt Eve a serpent. But technically speaking, all snakes can be called serpents, from the Latin derpere, meaning to … Read more

Beavers make their complex domestic arrangements to improve security from predators and to move and store a reliable food supply. Dam building is only one of their construction activities, along with canal building and lodge building. The dammed-up ponds make an important contribution to the beavers’ well-being by creating storage at the right depth to … Read more

They are very closely related, so closely that they are now usually considered different races of the same species, Rangifer tarandus. Even the somewhat smaller domesticated reindeer are part of the same group. Caribou coloration varies widely, from nearly black to brown to gray to almost white, and some populations migrate hundreds of miles, with … Read more

Horses can doze standing up and spend more time upright than other animals, but get their deepest rest, the so-called REM sleep, only when lying down. In total relaxation, which rapid eye movement or dream sleep involves, the system of tendons and ligaments that keeps horses’ legs extended does not work. If a horse goes … Read more

Bears do hibernate, though not as deeply as some other hibernating animals. Deep hibernators spend most of the winter with drastically lowered body temperatures. Bears lower their body temperatures only slightly and continue to burn about 4,000 calories a day, resulting in a Zen-like state of watchful rest. They can quickly rouse themselves in response … Read more

The polar bear can breed with the brown bear, and the offspring would probably be fertile. But it would never happen in the wild. The ranges of polar and brown bears do not overlap, and even if two met, they would see each other as competitors, not mates. Such interbreeding has occurred in captivity, but … Read more

Pound for pound, a 40-pound wolverine, formally Gulo gulo, is simply stronger than many of its adversaries and is capable of killing animals much larger than itself. Wolves are probably aware of this. For example, a wolverine’s jaws are so strong that it can completely crush a frozen caribou’s large bones, part of its adaptation … Read more

All animals need various nutrients—things like amino acids and vitamins — to build and maintain their cells and to provide energy for bodily processes. Carnivorous animals get many of these nutrients ready-made from the other animals they eat. Vegetarian animals get the nutrients not just by chemically changing plant material through enzymatic processes but also … Read more

Dust mites are often referred to as tiny insects, but they are not. Instead, they are arachnids, part of the large group of eight-legged creatures that includes spiders and ticks. Several species of dust mite belong to the genus Dermatophagoides, a name that describes in Latin their way of life: They live mostly by devouring … Read more

It is partly a matter of appearances, with zoo animals less active at peak visiting hours, and partly a matter of normal rhythms of carnivore life. Lions in the wild are normally inactive for twenty to twenty-two hours a day because they need to conserve their energy for hunting, never being quite sure where their … Read more

It is hard to be sure, but depending on when the flies show up, you can make an educated guess. Flies have a particular amount of time to spend as egg, larva, and pupa before they climb out of the pupa. In the common fruit fly, this takes about eight to perhaps ten or twelve … Read more

In some species of cricket, the number of chirps per minute used by the male to attract females rises and falls along with the outside temperature, and can in fact be used as a rough thermometer. Since insects are small (with a high surface-to-volume ratio) and cold-blooded, with relatively slow metabolisms unless they are exerting … Read more