Post by rock on Apr 25, 2019 20:07:27 GMT 5
titanoboa
Titanoboa (/tiˌtɑːnoʊˈboʊə/) is an extinct genus of very large snakes that lived in what is now La Guajira in northeastern Colombia. They could grow up to 12.8 m (42 ft) long and reach a weight of 1,135 kg (2,500 lb).[1]
Fossils of Titanoboa have been found in the Cerrejón Formation,[2] and date to around 58 to 60 million years ago. The giant snake lived during the Middle to Late Paleocene epoch,[3] a 10-million-year period immediately following the Cretaceous-Paleogene extinction event.[4]
The only known species is Titanoboa cerrejonensis, the largest snake ever discovered,[3] which supplanted the previous record holder, Gigantophis.
Titanoboa inhabited the first recorded Neotropical forest in the world. It shared its ecosystem with large Crocodylomorpha and large turtles. The paleogeography of the Late Paleocene was a sheltered paralic (coastal) swamp area, sheltered by the emerging later Guajira hills in the west and the slowly rising present-day Serranía del Perijá in the east, with an open connection to the proto-Caribbean in the north.In this environment the tropical aquatic ferns of the genus Salvinia flourished, as evidenced by fossils found in Cerrejón, the Bogotá Formation and the Palermo Formation.
Palaeobiology
While initially thought to have been an apex predator of the Paleocene ecosystem in which it lived, analysis of the cranial elements of Titanoboa possess unique features relative to other boids. These features include high palatal and marginal tooth position counts, low-angled quadrate orientation, and reduced palatine-pterygoid and ptery. This has pointed to the genus being dominantly piscivorous; a trait unique to Titanoboa among all boids.
The size of T. cerrejonensis has also provided clues as to the earth's climate during its existence; because snakes are ectothermic, the discovery implies that the tropics, the creature's habitat, must have been warmer than previously thought, averaging about 32 °C (90 °F)
The warmer climate of the Earth during the time of T. cerrejonensis allowed cold-blooded snakes to attain much larger sizes than modern snakes. Today, larger ectothermic animals are found in the tropics, where it is hottest, and smaller ones are found farther from the equator.
However, other researchers disagree with the above climate estimate. For example, a 2009 study in the journal Nature applying the mathematical model used in the above study to an ancient lizard fossil from temperate Australia predicts that lizards currently living in tropical areas should be capable of reaching 10 to 14 m (33 to 46 ft), which is not the case.[12]
In another critique published in the same journal, Mark Denny, a specialist in biomechanics, noted that the snake was so large and was producing so much metabolic heat that the ambient temperature must have been four to six degrees cooler than the current estimate, or the snake would have overheated.
black rhinoceros
The black rhinoceros or hook-lipped rhinoceros (Diceros bicornis) is a species of rhinoceros, native to eastern and southern Africa including Botswana, Kenya, Malawi, Mozambique, Namibia, South Africa, Swaziland, Tanzania, Zambia, and Zimbabwe. Although the rhinoceros is referred to as black, its colors vary from brown to grey.
The other African rhinoceros is the white rhinoceros (Ceratotherium simum). The word "white" in the name "white rhinoceros" is often said to be a misinterpretation of the Afrikaans word wyd (Dutch wijd) meaning wide, referring to its square upper lip, as opposed to the pointed or hooked lip of the black rhinoceros. These species are now sometimes referred to as the square-lipped (for white) or hook-lipped (for black) rhinoceros.[5]
The species overall is classified as critically endangered (even though the South-western black rhinoceros is classified as vulnerable). Three subspecies have been declared extinct, including the western black rhinoceros, which was declared extinct by the International Union for Conservation of Nature (IUCN) in 2011. The species was first named Rhinoceros bicornis by Carl Linnaeus in the 10th edition of his Systema naturae in 1758. The name means "double-horned rhinoceros". There is some confusion about what exactly Linnaeus conceived under this name as this species was probably based upon the skull of a single-horned Indian rhinoceros (Rhinoceros unicornis), with a second horn artificially added by the collector. Such a skull is known to have existed and Linnaeus even mentioned India as origin of this species. However he also referred to reports from early travellers about a double-horned rhino in Africa and when it emerged that there is only one, single-horned species of rhino in India, "Rhinoceros" bicornis was used to refer to the African rhinos (the white rhino only became recognised in 1812).[8] In 1911 this was formally fixed and the Cape of Good Hope officially declared the type locality of the species.Black rhinoceros are generally thought to be solitary, with the only strong bond between a mother and her calf. In addition, males and females have a consort relationship during mating, also subadults and young adults frequently form loose associations with older individuals of either sex.[33] They are not very territorial and often intersect other rhino territories. Home ranges vary depending on season and the availability of food and water. Generally they have smaller home ranges and larger density in habitats that have plenty of food and water available, and vice versa if resources are not readily available. Sex and age of an individual black rhino influence home range and size, with ranges of females larger than those of males, especially when accompanied by a calf.[34] In the Serengeti home ranges are around 70 to 100 km2 (27 to 39 sq mi), while in the Ngorongoro it is between 2.6 to 58.0 km2 (1.0 to 22.4 sq mi).[33] Black rhinos have also been observed to have a certain area they tend to visit and rest frequently called "houses" which are usually on a high ground level.[citation needed] These "home" ranges can vary from 2.6 km2 to 133 km2 with smaller home ranges having more abundant resources than larger home ranges.
Black rhinoceros in captivity and reservations sleep patterns have been recently studied to show that males sleep longer on average than females by nearly double the time. Other factors that play a role in their sleeping patterns is the location of where they decide to sleep. Although they do not sleep any longer in captivity, they do sleep at different times due to their location in captivity, or section of the park.
The black rhino has a reputation for being extremely aggressive, and charges readily at perceived threats. They have even been observed to charge tree trunks and termite mounds.[citation needed] Black rhinos will fight each other, and they have the highest rates of mortal combat recorded for any mammal: about 50% of males and 30% of females die from combat-related injuries.[37] Adult rhinos normally have no natural predators, thanks to their imposing size as well as their thick skin and deadly horns.[38] However, adult black rhinos have fallen prey to crocodiles in exceptional circumstances.Calves and, very seldom, small sub-adults may be preyed upon by lions as well.[3]
Black rhinoceros follow the same trails that elephants use to get from foraging areas to water holes. They also use smaller trails when they are browsing. They are very fast and can get up to speeds of 55 kilometres per hour (34 mph) running on their toes.
The black rhinoceros is a herbivorous browser that eats leafy plants, branches, shoots, thorny wood bushes, and fruit.[42] The optimum habitat seems to be one consisting of thick scrub and bushland, often with some woodland, which supports the highest densities. Their diet can reduce the amount of woody plants, which may benefit grazers (who focus on leaves and stems of grass), but not competing browsers (who focus on leaves, stems of trees, shrubs or herbs). It has been known to eat up to 220 species of plants. They have a significantly restricted diet with a preference for a few key plant species and a tendency to select leafy species in the dry season.[43] The plant species they seem to be most attracted to when not in dry season are the woody plants. There are 18 species of woody plants known to the diet of the black rhinoceros, and 11 species that could possibly be a part of their diet too.[44] Black rhinoceros also have a tendency to choose food based on quality over quantity, where researchers find more populations in areas where the food has better quality.[45] In accordance with their feeding habit, adaptations of the chewing apparatus have been described for rhinos. The black rhinoceros has a twophased chewing activity with a cutting ectoloph and more grinding lophs on the lingual side. The black rhinoceros can also be considered a more challenging herbivore to feed in captivity compared to its grazing relatives.[46] It can live up to 5 days without water during drought. Black rhinos live in several habitats including bushlands, Riverine woodland, marshes, and their least favorable, grasslands. Habitat preferences are shown in two ways, the amount of sign found in the different habitats, and the habitat content of home ranges and core areas. Habitat types are also identified based on the composition of dominant plant types in each area. Different subspecies live in different habitats including Vachellia and Senegalia savanna, Euclea bushlands, Albany thickets, and even desert.[33] They browse for food in the morning and evening. They are selective browsers but, studies done in Kenya show that they do add the selection material with availability in order to satisfy their nutritional requirements.[47] In the hottest part of the day they are most inactive- resting, sleeping, and wallowing in mud. Wallowing helps cool down body temperature during the day and protects against parasites. When black rhinos browse they use their lips to strip the branches of their leaves. Competition with elephants is causing the black rhinoceros to shift its diet. The black rhinoceros alters its selectivity with the absence of the elephant.
Titanoboa (/tiˌtɑːnoʊˈboʊə/) is an extinct genus of very large snakes that lived in what is now La Guajira in northeastern Colombia. They could grow up to 12.8 m (42 ft) long and reach a weight of 1,135 kg (2,500 lb).[1]
Fossils of Titanoboa have been found in the Cerrejón Formation,[2] and date to around 58 to 60 million years ago. The giant snake lived during the Middle to Late Paleocene epoch,[3] a 10-million-year period immediately following the Cretaceous-Paleogene extinction event.[4]
The only known species is Titanoboa cerrejonensis, the largest snake ever discovered,[3] which supplanted the previous record holder, Gigantophis.
Titanoboa inhabited the first recorded Neotropical forest in the world. It shared its ecosystem with large Crocodylomorpha and large turtles. The paleogeography of the Late Paleocene was a sheltered paralic (coastal) swamp area, sheltered by the emerging later Guajira hills in the west and the slowly rising present-day Serranía del Perijá in the east, with an open connection to the proto-Caribbean in the north.In this environment the tropical aquatic ferns of the genus Salvinia flourished, as evidenced by fossils found in Cerrejón, the Bogotá Formation and the Palermo Formation.
Palaeobiology
While initially thought to have been an apex predator of the Paleocene ecosystem in which it lived, analysis of the cranial elements of Titanoboa possess unique features relative to other boids. These features include high palatal and marginal tooth position counts, low-angled quadrate orientation, and reduced palatine-pterygoid and ptery. This has pointed to the genus being dominantly piscivorous; a trait unique to Titanoboa among all boids.
The size of T. cerrejonensis has also provided clues as to the earth's climate during its existence; because snakes are ectothermic, the discovery implies that the tropics, the creature's habitat, must have been warmer than previously thought, averaging about 32 °C (90 °F)
The warmer climate of the Earth during the time of T. cerrejonensis allowed cold-blooded snakes to attain much larger sizes than modern snakes. Today, larger ectothermic animals are found in the tropics, where it is hottest, and smaller ones are found farther from the equator.
However, other researchers disagree with the above climate estimate. For example, a 2009 study in the journal Nature applying the mathematical model used in the above study to an ancient lizard fossil from temperate Australia predicts that lizards currently living in tropical areas should be capable of reaching 10 to 14 m (33 to 46 ft), which is not the case.[12]
In another critique published in the same journal, Mark Denny, a specialist in biomechanics, noted that the snake was so large and was producing so much metabolic heat that the ambient temperature must have been four to six degrees cooler than the current estimate, or the snake would have overheated.
black rhinoceros
The black rhinoceros or hook-lipped rhinoceros (Diceros bicornis) is a species of rhinoceros, native to eastern and southern Africa including Botswana, Kenya, Malawi, Mozambique, Namibia, South Africa, Swaziland, Tanzania, Zambia, and Zimbabwe. Although the rhinoceros is referred to as black, its colors vary from brown to grey.
The other African rhinoceros is the white rhinoceros (Ceratotherium simum). The word "white" in the name "white rhinoceros" is often said to be a misinterpretation of the Afrikaans word wyd (Dutch wijd) meaning wide, referring to its square upper lip, as opposed to the pointed or hooked lip of the black rhinoceros. These species are now sometimes referred to as the square-lipped (for white) or hook-lipped (for black) rhinoceros.[5]
The species overall is classified as critically endangered (even though the South-western black rhinoceros is classified as vulnerable). Three subspecies have been declared extinct, including the western black rhinoceros, which was declared extinct by the International Union for Conservation of Nature (IUCN) in 2011. The species was first named Rhinoceros bicornis by Carl Linnaeus in the 10th edition of his Systema naturae in 1758. The name means "double-horned rhinoceros". There is some confusion about what exactly Linnaeus conceived under this name as this species was probably based upon the skull of a single-horned Indian rhinoceros (Rhinoceros unicornis), with a second horn artificially added by the collector. Such a skull is known to have existed and Linnaeus even mentioned India as origin of this species. However he also referred to reports from early travellers about a double-horned rhino in Africa and when it emerged that there is only one, single-horned species of rhino in India, "Rhinoceros" bicornis was used to refer to the African rhinos (the white rhino only became recognised in 1812).[8] In 1911 this was formally fixed and the Cape of Good Hope officially declared the type locality of the species.Black rhinoceros are generally thought to be solitary, with the only strong bond between a mother and her calf. In addition, males and females have a consort relationship during mating, also subadults and young adults frequently form loose associations with older individuals of either sex.[33] They are not very territorial and often intersect other rhino territories. Home ranges vary depending on season and the availability of food and water. Generally they have smaller home ranges and larger density in habitats that have plenty of food and water available, and vice versa if resources are not readily available. Sex and age of an individual black rhino influence home range and size, with ranges of females larger than those of males, especially when accompanied by a calf.[34] In the Serengeti home ranges are around 70 to 100 km2 (27 to 39 sq mi), while in the Ngorongoro it is between 2.6 to 58.0 km2 (1.0 to 22.4 sq mi).[33] Black rhinos have also been observed to have a certain area they tend to visit and rest frequently called "houses" which are usually on a high ground level.[citation needed] These "home" ranges can vary from 2.6 km2 to 133 km2 with smaller home ranges having more abundant resources than larger home ranges.
Black rhinoceros in captivity and reservations sleep patterns have been recently studied to show that males sleep longer on average than females by nearly double the time. Other factors that play a role in their sleeping patterns is the location of where they decide to sleep. Although they do not sleep any longer in captivity, they do sleep at different times due to their location in captivity, or section of the park.
The black rhino has a reputation for being extremely aggressive, and charges readily at perceived threats. They have even been observed to charge tree trunks and termite mounds.[citation needed] Black rhinos will fight each other, and they have the highest rates of mortal combat recorded for any mammal: about 50% of males and 30% of females die from combat-related injuries.[37] Adult rhinos normally have no natural predators, thanks to their imposing size as well as their thick skin and deadly horns.[38] However, adult black rhinos have fallen prey to crocodiles in exceptional circumstances.Calves and, very seldom, small sub-adults may be preyed upon by lions as well.[3]
Black rhinoceros follow the same trails that elephants use to get from foraging areas to water holes. They also use smaller trails when they are browsing. They are very fast and can get up to speeds of 55 kilometres per hour (34 mph) running on their toes.
The black rhinoceros is a herbivorous browser that eats leafy plants, branches, shoots, thorny wood bushes, and fruit.[42] The optimum habitat seems to be one consisting of thick scrub and bushland, often with some woodland, which supports the highest densities. Their diet can reduce the amount of woody plants, which may benefit grazers (who focus on leaves and stems of grass), but not competing browsers (who focus on leaves, stems of trees, shrubs or herbs). It has been known to eat up to 220 species of plants. They have a significantly restricted diet with a preference for a few key plant species and a tendency to select leafy species in the dry season.[43] The plant species they seem to be most attracted to when not in dry season are the woody plants. There are 18 species of woody plants known to the diet of the black rhinoceros, and 11 species that could possibly be a part of their diet too.[44] Black rhinoceros also have a tendency to choose food based on quality over quantity, where researchers find more populations in areas where the food has better quality.[45] In accordance with their feeding habit, adaptations of the chewing apparatus have been described for rhinos. The black rhinoceros has a twophased chewing activity with a cutting ectoloph and more grinding lophs on the lingual side. The black rhinoceros can also be considered a more challenging herbivore to feed in captivity compared to its grazing relatives.[46] It can live up to 5 days without water during drought. Black rhinos live in several habitats including bushlands, Riverine woodland, marshes, and their least favorable, grasslands. Habitat preferences are shown in two ways, the amount of sign found in the different habitats, and the habitat content of home ranges and core areas. Habitat types are also identified based on the composition of dominant plant types in each area. Different subspecies live in different habitats including Vachellia and Senegalia savanna, Euclea bushlands, Albany thickets, and even desert.[33] They browse for food in the morning and evening. They are selective browsers but, studies done in Kenya show that they do add the selection material with availability in order to satisfy their nutritional requirements.[47] In the hottest part of the day they are most inactive- resting, sleeping, and wallowing in mud. Wallowing helps cool down body temperature during the day and protects against parasites. When black rhinos browse they use their lips to strip the branches of their leaves. Competition with elephants is causing the black rhinoceros to shift its diet. The black rhinoceros alters its selectivity with the absence of the elephant.
