Birds, a subgroup of Reptiles, are the last living examples of Dinosaurs. Birds live worldwide and range in size from the 5 cm bee hummingbird to the 2.75 m ostrich. They rank as the class of tetrapods with the most living species, at ten thousand. Birds are the closest living relatives of crocodilians, the fossil record indicates that birds evolved from feathered ancestors within the theropod group of saurischian dinosaurs. True birds first appeared during the Cretaceous period, around 100 million years ago, especially those in the southern continents, survived this event and migrated to other parts of the world while diversifying during periods of global cooling. Primitive bird-like dinosaurs that lie outside class Aves proper, in the broader group Avialae, have been found dating back to the mid-Jurassic period, around 170 million years ago. Birds have wings which are more or less developed depending on the species, the digestive and respiratory systems of birds are uniquely adapted for flight.
Some bird species of aquatic environments, particularly seabirds and some waterbirds, have evolved for swimming. Many species annually migrate great distances, Birds are social, communicating with visual signals and bird songs, and participating in such social behaviours as cooperative breeding and hunting and mobbing of predators. The vast majority of species are socially monogamous, usually for one breeding season at a time, sometimes for years. Other species have breeding systems that are polygynous or, Birds produce offspring by laying eggs which are fertilised through sexual reproduction. They are usually laid in a nest and incubated by the parents, most birds have an extended period of parental care after hatching. Some birds, such as hens, lay eggs even when not fertilised, songbirds and other species are popular as pets. Guano is harvested for use as a fertiliser, Birds prominently figure throughout human culture. About 120–130 species have become extinct due to human activity since the 17th century, human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them.
Recreational birdwatching is an important part of the ecotourism industry, the first classification of birds was developed by Francis Willughby and John Ray in their 1676 volume Ornithologiae. Carl Linnaeus modified that work in 1758 to devise the taxonomic classification system currently in use, Birds are categorised as the biological class Aves in Linnaean taxonomy. Phylogenetic taxonomy places Aves in the dinosaur clade Theropoda, Aves and a sister group, the clade Crocodilia, contain the only living representatives of the reptile clade Archosauria
A parakeet is any one of a large number of small to medium-sized species of parrot, in multiple genera, that generally have long tail feathers. Older spellings still sometimes encountered are paroquet or paraquet, the name parakeet is derived from the French perroquet. It is however a false cognate as perroquet means parrot in French, the Australian budgerigar, known as budgie or English parakeet or keet, Melopsittacus undulatus, is probably the most common parakeet. It was first described by zoologists in 1891 and it is the most popular species of parakeet kept as a pet in North America and Europe. The term grass parakeet refers to a number of small Australian parakeets native to grasslands such as the Neophema genus. The Australian rosellas are parakeets, many of the smaller, long-tailed species of lories may be referred to as lorikeets. The vernacular name ringnecked parakeet refers to a species of the Psittacula genus native to Africa and Asia that is popular as a pet and has become feral in many cities outside its natural range.
In aviculture, the term conure is used for small to medium-sized parakeets of the genera Aratinga, and a few genera of the tribe Arini. As they are not all from one genus, taxonomists tend to avoid the term, other South American species commonly called parakeets include the genus Brotogeris parakeets, the monk parakeet, and lineolated parakeets, although lineolateds have short tails. A larger species may be referred to as parrot or parakeet interchangeably, for example, Alexandrine parrot and Alexandrine parakeet are two common names for the same species, Psittacula eupatria, which is one of the largest species normally referred to as a parakeet. Many different species of parakeets are bred and sold commercially as pets, budgerigars are great companions for any age and can be easily trained if bonded very closely with pet parent. Parakeets often breed more readily in groups, there can be conflicts between breeding pairs and individuals especially if space is limited, parakeets produce about six to eight eggs if the parakeet successfully lays eggs
The white-nosed coati, known as the coatimundi, is a species of coati and a member of the family Procyonidae. Local names include pizote and tejón, males are much larger than females, and small females weigh as little as 2.5 kg and large males as much as 12.2 kg. On average, the length is about 110 cm, about half of that being the tail length. White-nosed coatis inhabit wooded areas of the Americas and they are found at any altitude from sea level to 3,000 m, and from as far north as southeastern Arizona and New Mexico, through Mexico and Central America, to far northwestern Colombia. There has been confusion over its southern range limit, but specimen records from most of Colombia. They are smaller than white-nosed coatis from the adjacent mainland, the level of other differences support its status as a subspecies rather than separate species. White-nosed coatis have found in the U. S. state of Florida. It is unknown precisely when introduction occurred, a specimen in the Florida Museum of Natural History, labeled an escaped captive.
There are several documented cases of coatis escaping captivity, and since the 1970s there have been a number of sightings. These reports have occurred over an area of southern Florida. They are omnivores, preferring small vertebrates, carrion, insects and they can climb trees easily, where the tail is used for balance, but they are most often on the ground foraging. Their predators include boas, hunting cats, and Tayras and they readily adapt to human presence, like raccoons, they will raid campsites and trash receptacles. They can be tamed easily, and have been verified experimentally to be quite intelligent, while the raccoon and ringtail are nocturnal, coatis are active by day, retiring during the night to a specific tree and descending at dawn to begin their daily search for food. However, their habits are adjustable, and in areas where they are hunted by humans for food, or where they raid human settlements for their own food, adult males are solitary, but females and sexually immature males form social groups.
They use many vocal signals to communicate with one another, and spend time grooming themselves and each other with their teeth, during foraging times, the young cubs are left with a pair of babysitters, similar to meerkats. The young males and even some females tend to play-fight, many of the coatis will have short fights over food. Smithsonian Institution – North American Mammals, Nasua narica Smithsonian Wild, Nasua narica
A rip current, often referred to simply as a rip, or by the misnomer rip tide, is a specific kind of water current which can occur near beaches with breaking waves. Rip currents can be hazardous to people in the water, because of these factors, rips are the leading cause of rescues by lifeguards at beaches, and in the US rips are the cause of an average of 46 deaths by drowning per year. A rip current is not the thing as undertow, although some people use the latter term incorrectly when they mean a rip current. Contrary to popular belief, neither rip nor undertow can pull a person down, a rip simply carries floating objects, including people, out beyond the zone of the breaking waves. When there is an area which is slightly deeper or a break in an offshore bar or reef, this can allow water to flow offshore more easily. When the water in the rip current reaches outside of the lines of breaking waves, the flow disperses sideways, loses power, and dissipates in what is known as the head of the rip.
Rip currents can occur on a gently shelving shore where breaking waves approach near perpendicular to the average shoreline and they can form at the coasts of oceans and large lakes when there are waves with sufficient energy. The location of rip currents can be difficult to predict, while some tend to recur always in the same place, others can appear and disappear suddenly at various locations along the beach. This will depend on the topography and the direction of the waves. Rip currents can occur wherever there is strong longshore variability in wave breaking. Rip currents are quite narrow, but tend to be more common and faster, when. Local underwater topography makes some more likely to have rip currents. A fairly common misconception is that rip currents can pull a swimmer down and this is not true, and in reality a rip current is strongest close to the surface, as the flow near the bottom is slowed by friction. A more detailed description involves radiation stress and this is the force exerted on the water column by the presence of the wave.
As a wave shoals and increases in height prior to breaking, to balance this, the local mean surface level drops — this is known as setdown. As the wave breaks and continues to reduce in height, the stress decreases. To balance this force, the mean surface increases—this is known as setup, as a wave propagates over a sandbar with a gap, the wave breaks on the bar, leading to setup. However, the part of the wave propagates over the gap does not break
A national park is a park in use for conservation purposes. Often it is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns, although individual nations designate their own national parks differently, there is a common idea, the conservation of wild nature for posterity and as a symbol of national pride. An international organization, the International Union for Conservation of Nature, although Yellowstone was not officially termed a national park in its establishing law, it was always termed such in practice and is widely held to be the first and oldest national park in the world. The first area to use national park in its legislation was the USs Mackinac Island. Australias Royal National Park, established in 1879, was the third official national park. In 1895 ownership of Mackinac Island was transferred to the State of Michigan as a state park, as a result, Australias Royal National Park is by some considerations the second oldest national park now in existence.
The largest national park in the meeting the IUCN definition is the Northeast Greenland National Park. According to the IUCN,6,555 national parks worldwide met its criteria in 2006, IUCN is still discussing the parameters of defining a national park. National parks are almost always open to visitors, in 1971, these criteria were further expanded upon leading to more clear and defined benchmarks to evaluate a national park. In 1810, the English poet William Wordsworth described the Lake District as a sort of property, in which every man has a right and interest who has an eye to perceive. It was known as Hot Springs Reservation, but no authority was established. Federal control of the area was not clearly established until 1877, John Muir is today referred to as the Father of the National Parks due to his work in Yosemite. He published two articles in The Century Magazine, which formed the base for the subsequent legislation. President Abraham Lincoln signed an Act of Congress on July 1,1864, ceding the Yosemite Valley, according to this bill, private ownership of the land in this area was no longer possible.
The state of California was designated to manage the park for use, resort. Leases were permitted for up to ten years and the proceeds were to be used for conservation, a public discussion followed this first legislation of its kind and there was a heated debate over whether the government had the right to create parks. The perceived mismanagement of Yosemite by the Californian state was the reason why Yellowstone at its establishment six years was put under national control, in 1872, Yellowstone National Park was established as the United States first national park, being the worlds first national park. In some European countries, national protection and nature reserves already existed, such as Drachenfels, Yellowstone was part of a federally governed territory
Hoffmann's two-toed sloth
Hoffmanns two-toed sloth is a species of sloth from Central and South America. It is a solitary, largely nocturnal and arboreal animal, found in mature and secondary rainforests, the common name commemorates the German naturalist Karl Hoffmann. Hoffmanns two-toed sloth is a heavily built animal with shaggy fur and slow, the fore feet have only two toes, each ending with long, curved claws, although three clawed toes are on each of the hind feet. The wrist of the sloth has developed some specific traits due to their slow, Hoffmanns two-toed sloth is, much easier to confuse with the related Linnaeuss two-toed sloth, which it closely resembles. Adults range from 54 to 72 cm in length. Although they do have stubby tails, just 1.5 to 3 cm long, the claws are 5 to 6.5 cm long. Females are larger on average than males, although with considerable overlap in size and their fur is tan to light brown in colour, being lighter on the face, but usually has a greenish tinge because of the presence of algae living in the hairs.
Its karyotype has 2n = 49–51 and FN =61, Hoffmanns two-toed sloth inhabits tropical forests from sea level to 3,300 m above sea level. It is found in the rainforest canopy in two regions of Central and South America, separated by the Andes. One population is found from eastern Honduras in the north to western Ecuador in the south, and the other in eastern Peru, western Brazil, based on cytochrome c oxidase subunit I sequences, a divergence date of about 7 million years between these populations has been suggested. A study of sloths on Barro Colorado Island indicated that the Hoffmanns two-toed sloths there were almost exclusively nocturnal, the authors attributed this in part to competition with the brown-throated sloth. They often move slowly through the canopy for about eight hours each night and they move only very slowly, typically at around 0.14 m/s, although they can move up to 50% faster when excited. They are solitary in the wild, aside from mothers with young, the name sloth means lazy, but the slow movements of this animal are actually an adaptation for surviving on a low-energy diet of leaves.
These sloths have half the rate of a typical mammal of the same size. Sloths have very poor eyesight and hearing, and rely almost entirely on their senses of touch and this species often exhibits exaggerated wobbling of the head. Another trait of this sloth is it often spits when the mouth opens, the saliva often accumulates on the lower lip, giving the creature a comical appearance. Two-toed sloths hang from branches, suspended by their huge. The clinging behaviour is an action, and sloths are found still hanging from trees after they die
Snorkeling is the practice of swimming on or through a body of water while equipped with a diving mask, a shaped breathing tube called a snorkel, and usually swimfins. In cooler waters, a wetsuit may be worn, use of this equipment allows the snorkeler to observe underwater attractions for extended periods with relatively little effort and to breathe while face-down at the surface. Snorkeling is a recreational activity, particularly at tropical resort locations. The primary appeal is the opportunity to observe life in a natural setting without the complicated equipment. It appeals to all ages because of how little there is. It is the basis of the two disciplines of the underwater sport of finswimming. Snorkeling is mentioned by Aristotle in his Parts of Animals and he refers to divers using instruments for respiration resembling the elephants trunk. The snorkel may be an item or may be integrated with a full-face snorkelling mask. The integrated system is suitable for surface snorkelling, but the separate snorkel may be used for free-diving.
It is used for breathing air from above the surface when the wearers mouth and nose are submerged. The snorkel may have a piece of rubber or a clip that attaches the snorkel to the outside of the strap of the diving mask. An alternative technique is fitting the snorkel between the mask-strap and the head, but this practice may increase the chance that the mask leaks, the optimum design length of the snorkel tube is at most 40 centimeters. A longer tube would not allow breathing when snorkelling deeper, since it would place the lungs in deeper water where the water pressure is higher. The lungs would be unable to inflate when the snorkeler inhales, the pressure difference across the tissues in the lungs, between the blood capillaries and air spaces would increase the risk of pulmonary edema. The greater the volume of the tube, and the smaller the tidal volume of breathing, a smaller diameter tube reduces the dead volume, but increases resistance to airflow and so increases the work of breathing.
Occasional exhalation through the nose while snorkeling will slightly reduce the buildup of carbon dioxide, the simplest type of snorkel is a plain tube that is allowed to flood when underwater. The displacement method expels water by filling the snorkel with air, it is a technique that takes practice but clears the snorkel with less effort, clearing splash water while at the surface requires blast clearing. Some snorkels have a sump at the lowest point to allow a volume of water to remain in the snorkel without being inhaled when the snorkeler breathes
Dolphins are a widely distributed and diverse group of aquatic mammals. They are a grouping within the order Cetacea, excluding whales and porpoises. The dolphins comprise the extant families Delphinidae, Platanistidae and Pontoporiidae, there are 40 extant species of dolphins. Dolphins, alongside other cetaceans, belong to the clade Cetartiodactyla with even-toed ungulates and their closest living relatives are the hippopotamuses, having diverged about 40 million years ago. Dolphins range in size from the 1.7 m long and 50 kg Mauis dolphin to the 9.5 m and 10 t killer whale, several species exhibit sexual dimorphism, in that the males are larger than females. They have streamlined bodies and two limbs that are modified into flippers, though not quite as flexible as seals, some dolphins can travel at 55.5 km/h. Dolphins use their conical shaped teeth to capture fast moving prey and they have well-developed hearing which is adapted for both air and water and is so well developed that some can survive even if they are blind.
Some species are adapted for diving to great depths. They have a layer of fat, or blubber, under the skin to keep warm in the cold water, although dolphins are widespread, most species prefer the warmer waters of the tropic zones, but some, like the right whale dolphin, prefer colder climates. Dolphins feed largely on fish and squid, but a few, like the killer whale, feed on large mammals, male dolphins typically mate with multiple females every year, but females only mate every two to three years. Calves are typically born in the spring and summer months and females bear all the responsibility for raising them, mothers of some species fast and nurse their young for a relatively long period of time. Dolphins produce a variety of vocalizations, usually in the form of clicks, Dolphins are sometimes hunted in places like Japan, in an activity known as dolphin drive hunting. Besides drive hunting, they face threats from bycatch, habitat loss. Dolphins have been depicted in cultures worldwide. Dolphins occasionally feature in literature and film, as in the film series Free Willy, Dolphins are sometimes kept in captivity and trained to perform tricks, but breeding success has been poor and the animals often die within a few months of capture.
The most common dolphins kept are killer whales and bottlenose dolphins, the name is originally from Greek δελφίς, which was related to the Greek δελφύς, womb. The animals name can therefore be interpreted as meaning a fish with a womb, the name was transmitted via the Latin delphinus, which in Medieval Latin became dolfinus and in Old French daulphin, which reintroduced the ph into the word. The term mereswine has historically been used, the term dolphin can be used to refer to, under the parvorder Odontoceti, all the species in the family Delphinidae and the river dolphin families Iniidae, Pontoporiidae and Platanistidae
Potoos are a group of near passerine birds related to the nightjars and frogmouths. They are sometimes called poor-me-ones, after their haunting calls, there are seven species in one genus, Nyctibius, in tropical Central and South America. These are nocturnal insectivores which lack the bristles around the mouth found in the true nightjars and they hunt from a perch like a shrike or flycatcher. During the day they perch upright on tree stumps, camouflaged to look like part of the stump, the single spotted egg is laid directly on the top of a stump. The potoos are today an exclusively New World family, but they apparently had a more widespread distribution in the past. Fossil remains of potoos dating from the Oligocene and Eocene have been found in France, a complete skeleton of the genus Paraprefica has been found in Messel, Germany. It had skull and leg features similar to those of modern potoos, a 1996 study of the mitochondrial DNA of the potoos supported the monophyly of the family although it did not support the previous assumption that it was closely related to the oilbirds.
The study found a deal of genetic divergence between the species, suggesting that these species are themselves very old. The level of divergence is the highest of any genus of birds and this raises the possibility that there are several cryptic species to be discovered. For example, the northern potoo was for a time considered to be the same species as the common potoo. In spite of there is no morphological way to separate the two species. The potoos are a conservative family in appearance, with all the species closely resembling one another. Potoos range from 21–58 cm in length and they resemble upright sitting nightjars, a closely related family. They resemble the frogmouths of Australasia, that are stockier and have heavier bills. They have proportionally large heads for their size and long wings. The large head is dominated by a broad bill and enormous eyes. In the treatment of the family in the Handbook of the Birds of the World, Cohn-Haft describes the potoos as little more than a flying mouth, the bill, while large and broad, is short, barely projecting past the face.
It is delicate, but has a tooth on the cutting edge of the upper mandible that may assist in foraging
The mantled howler, or golden-mantled howling monkey, is a species of howler monkey, a type of New World monkey, from Central and South America. It is one of the species most often seen and heard in the wild in Central America. It takes its name from the long guard hairs on its sides. The mantled howler is one of the largest Central American monkeys and it is the only Central American monkey that eats large quantities of leaves, it has several adaptations to this folivorous diet. Since leaves are difficult to digest and provide less energy than most foods, the male mantled howler has an enlarged hyoid bone, a hollow bone near the vocal cords, which amplifies the calls made by the male, and is the reason for the name howler. Howling allows the monkeys to locate each other without expending energy on moving or risking physical confrontation, the mantled howler lives in groups that can have over 40 members, although groups are usually smaller. Most mantled howlers of both sexes are evicted from the group they were born in upon reaching maturity, resulting in most adult group members being unrelated.
The most dominant male, the male, gets preference for food and resting places. The mantled howler is important to the rainforest ecology as a seed disperser, although it is affected by deforestation, it is able to adapt better than other species, due to its ability to feed on abundant leaves and its ability to live in a limited amount of space. The mantled howler belongs to the New World monkey family Atelidae and it is a member of the subfamily Alouattinae and genus Alouatta, the subfamily and genus containing all the howler monkeys. The species name is A. palliata, a pallium was a cloak or mantle worn by ancient Greeks and this refers to the long guard hairs, known as a mantle, on its sides. Two additional subspecies of the mantled howler are sometimes recognised, but these are generally recognised as subspecies of the Coiba Island howler. However, mitochondrial DNA testing of their status has been inconclusive, Azuero howler, Alouatta palliata trabeata, in Panama, Alouatta palliata coibensis, the mantled howlers appearance is similar to other howler monkeys of the genus Alouatta except for coloration.
The mantled howler is primarily black except for a fringe of yellow or golden brown hairs on the flanks of the body earning the common name mantled howler monkey. When the males reach maturity, the scrotum turns white, females are between 481 and 632 mm in body length, excluding tail, and males are between 508 and 675 mm. The prehensile tail is between 545 and 655 mm long, adult females generally weigh between 3.1 and 7.6 kg, while males typically weigh between 4.5 and 9.8 kg. Average body weights can vary significantly between monkey populations in different locations, the brain of an adult mantled howler is about 55.1 g, which is smaller than that of several smaller monkey species, such as the white-headed capuchin. The mantled howler shares several adaptations with other species of monkey that allow it to pursue a folivorous diet, that is