Hippopotamuses are large mammals found in sub-Saharan Africa. Their name comes from the Greek word for “river horse” because they’re often found in water, which helps them stay cool in the hot, tropical climate where they live.
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Scorpions are arachnids and have eight legs like their cousins—spiders, mites, and ticks. They can quickly grab an insect with their pincers and whip their telson, the poisonous tip of their tail forward and sting their prey. They use their poison to kill prey and to defend against predators. Scorpions look like small lobsters and may be the first animals to move from water to land hundreds of millions of years ago. They have been around since before the age of the dinosaurs. Fossils of scorpions from Scotland hundreds of millions of years ago show that their appearance hasn’t changed over the millennia, but they are now half the size of their ancient ancestors. Only 30 or 40 species around the world have strong enough poison to kill a person. Each species has a special type of venom that works well against a chosen prey. Scorpions typically eat insects, but when food is scarce, they can slow their metabolism to as little as one-third the typical rate for arthropods. This technique enables some species to use little oxygen and live on only one insect per year. Such survival skills allow scorpions to live in some of the planet’s toughest environments. Researchers have even frozen scorpions overnight, only to put them in the sun the next day and watch them thaw out and walk away. However, they are burrowing animals, so in areas of permafrost or heavy grasses, where loose soil is not available, scorpions may not be able to survive.
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Space explorers go above and beyond on the job. Here are five cool things about these pioneers.
You won’t find baths or showers in space.
Octopuses are sea animals famous for their rounded bodies, bulging eyes, and eight long arms. They live in all the world’s oceans but are especially abundant in warm, tropical waters. Octopuses, like their cousin, the squid, are often considered “monsters of the deep,” though some species, or types, occupy relatively shallow waters. Most octopuses stay along the ocean’s floor, although some species are pelagic, which means they live near the water’s surface. Other octopus species live in deep, dark waters, rising from below at dawn and dusk to search for food. Crabs, shrimps, and lobsters rank among their favorite foods, though some can attack larger prey, like sharks. Octopuses typically drop down on their prey from above and, using powerful suctions that line their arms, pull the animal into their mouth. The octopus performs its famous backward swim by blasting water through a muscular tube on the body called a siphon. Octopuses also crawl along the ocean’s floor, tucking their arms into small openings to search for food. Seals, whales, and large fish prey on octopuses. If threatened, octopuses shoot an inky fluid that darkens the water, confusing the aggressor. The octopus can also change to gray, brown, pink, blue, or green to blend in with its surroundings. Octopuses may also change color as a way to communicate with other octopuses. Octopuses are solitary creatures that live alone in dens built from rocks, which the octopus moves into place using its powerful arms. Octopuses sometimes even fashion a rock “door” for their den that pulls closed when the octopus is safely inside.
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The red-tailed hawk is a top predator. The hawks use tall perches to spot their prey in the open spaces next to highways. Red-tailed hawks also hunt from the air. As they circle and soar, they can spot a mouse from 100 feet (30 meters) up in the air—about ten stories high. When a red-tailed hawk spots a rodent, rabbit, lizard, or other prey scurrying, it swoops down and grabs its meal in its talons—the big claws on its feet. Once the hawk grabs its prey, it usually flies back up to its perch to eat it. They were named for the variety that has a brick-red tail. Male and female red-tailed hawks basically look alike, though the females are larger. Red-tailed hawks often mate for life. The pair makes a stick nest in a tree, high above the ground. They will use the nest year after year, so it grows bigger and bigger. The female hawk lays one to five eggs—which are white with brown spots. The parents take turns sitting on the eggs, keeping them warm and safe. Baby red-tailed hawks are covered with white, downy feathers. The hawk parents feed their young until the young birds can leave the nest, usually when they’re about six weeks old.
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When a great white shark is born, along with up to a dozen siblings, it immediately swims away from its mother. Born on the east and west coasts of North America, the south of Africa and southwest Australia, baby sharks are on their own right from the start. Their mother may see them only as prey. At birth the baby shark is already about 5 feet (1.5 meters) long; as it grows it may reach a length up to four times that. The pup (which is what a baby shark is called) will live its life at the top of the ocean’s food chain. But before it grows larger, the pup must avoid predators bigger than it is—including other great white sharks. Many baby sharks do not survive their first year. Young great white sharks eat fish (including other sharks) and rays. As they grow, the sharks’ favorite prey becomes sea mammals, especially sea lions and seals. Sharks count on the element of surprise as they hunt. When they see a seal at the surface of the water, sharks will often position themselves underneath the seal. Using their tails as propellers, they swim upward at a fast sprint, burst out of the water in a leap called a breach, and fall back into the water with the seal in their mouths. They can smell a single drop of blood from up to a third of a mile (0.53 kilometers) away. Sharks don’t chew their food; they rip off chunks of meat and swallow them whole. They can last a month or two without another big meal.
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A female red-eyed tree frog has laid a batch of eggs on a leaf. She chose the spot carefully—the leaf hangs over a pond. When the eggs are ready to hatch, the tadpoles inside start swirling around vigorously. The activity breaks each egg open, releasing the little tadpoles. All the tadpoles wash down the leaf in a little stream of moisture from the hatching eggs, and—plop! plop! plop!—they land in the pond below. Feeding on tiny insects, the tadpoles live in the water they fell into until they metamorphose, or develop, into little brown froglets. At this point they leave the water and climb up nearby trees to live as tree frogs. By the time they’re adults, the frogs have turned a striking green, with blue-and-yellow striped sides, orange or red feet, a flash of blue on their thighs, and big red eyes. The bright colors are a defense mechanism. Being green helps the red-eyed tree frog blend in with tree leaves. If the green camouflage fails and a predator spots a sleeping frog, it swoops in for what it thinks will be a tasty meal. But the awakened frog’s eyes pop open, revealing their startling bright red color! Also, when the frog rushes to get away, it untucks its brightly colored legs. The predator is often so surprised by these sudden flashes of color that it is momentarily confused and hesitates. And while it does, the frog has a split second to make its escape!
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Goblin Shark
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Female black widows are shiny black, with a red-orange hourglass pattern on their abdomen. Male black widows are not black, but brown or gray with small red spots. Black widows are poisonous arachnids—animals that have a skeleton outside their body, a segmented body, and eight jointed legs. They are not insects. Their deadly poison is said to be 15 times stronger than rattlesnake venom. Black widows use a silk-like substance to weave tangled-looking webs, typically close to the ground in covered or dark places, such as near drain pipes or under logs. The female hangs upside down in the web to await her prey, exposing her bright markings as a warning to potential predators. The black widow senses vibrations to the web. When an unlucky intruder gets trapped, the spider immediately begins weaving its glue-like webbing around it. Insects such as flies, mosquitoes, or even larger prey like grasshoppers are typically caught. Once captured, the black widow injects its victims with poison, paralyzing them. The tips of the black widow’s legs are coated with an oily substance that prevents the black widow from getting caught in its own web. Adult male and female black widows live solitary lives, meeting only to breed. The female black widow lays approximately 200 eggs. The eggs incubate for some 20 days in a small, round papery sac that’s attached to the mother’s web. After hatching, the baby spiders stay in the cocoon for up to one month. Three species of poisonous North American spiders carry the common name black widow under the genus Latrodectus. Each species occupies a distinct region of North America, as their names suggest: Eastern black widows (L. mactans), northern black widows (L. variolus), and western black widows (L. hesperus). These three species have very similar physical and behavioral characteristics. The name “black widow” comes from the female’s habit of eating the male after mating.
The female black widow is approximately 1.5 inches (38 millimeters) long. The male is about half the female’s size.
The black widow is prey for birds and other spiders. Although poisonous, the black widow is not considered aggressive unless threatened. In fact, the male black widow is reclusive and hardly ever seen by humans. While the black widow’s poison is rarely fatal to humans, it can cause severe pain and nausea.
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