|
Tana River Mangabey
The Tana River mangabey (''Cercocebus galeritus'') is a highly endangered species of primate in the family Cercopithecidae. Some authorities have included the taxa ''agilis'' and '' sanjei'' as subspecies of this species, while others award these full species status. It is endemic to riverine forest patches along the lower Tana River in southeastern Kenya. It is threatened by habitat loss and degradation, which has increased in recent years. This species was, together with the equally endangered Tana River red colobus, the main reason for the creation of the Tana River Primate Reserve in 1978, but human encroachment within this reserve continues. Recently, it has been suggested that 20,000 hectares of the Tana River Delta should be transformed into sugarcane plantations, but this has, temporarily at least, been stopped by the High Court of Kenya. Physical description The Tana River mangabey is a medium-sized primate with a long semi-prehensile tail, yellow-brown coat, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelm Peters
Wilhelm Karl Hartwich (or Hartwig) Peters (22 April 1815 in Koldenbüttel – 20 April 1883) was a German natural history, naturalist and explorer. He was assistant to the anatomist Johannes Peter Müller and later became curator of the Natural History Museum, Berlin, Berlin Zoological Museum. Encouraged by Müller and the explorer Alexander von Humboldt, Peters travelled to Mozambique via Angola in September 1842, exploring the coastal region and the Zambesi River. He returned to Berlin with an enormous collection of natural history specimens, which he then described in ''Naturwissenschaftliche Reise nach Mossambique... in den Jahren 1842 bis 1848 ausgeführt'' (1852–1882). The work was comprehensive in its coverage, dealing with mammals, birds, reptiles, amphibians, river fish, insects and botany. He replaced Martin Lichtenstein as curator of the museum in 1858, and in the same year he was elected a foreign member of the Royal Swedish Academy of Sciences. In a few years, he g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dental Morphology
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology (that is, the relationship between the shape and form of the tooth in question and its inferred function) of the teeth of an animal. Animals whose teeth are all of the same type, such as most non-mammalian vertebrates, are said to have ''homodont'' dentition, whereas those whose teeth differ morphologically are said to have ''heterodont'' dentition. The dentition of animals with two successions of teeth (deciduous, permanent) is referred to as ''diphyodont'', while the dentition of animals with only one set of teeth throughout life is ''monophyodont''. The dentition of animals in which the teeth are continuously discarded and replaced throughout life is termed ''polyphyodont''. The dentition of animals in which the teeth are set in socke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gestation Period
In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus, and ends once it leaves the uterus. Fertilization and implantation During copulation, the male inseminates the female. The spermatozoon fertilizes an ovum or various ova in the uterus or fallopian tubes, and this results in one or multiple zygotes. Sometimes, a zygote can be created by humans outside of the animal's body in the artificial process of in-vitro fertilization. After fertilization, the newly formed zygote then begins to divide through mitosis, forming an embryo, which implants in the female's endometrium. At this time, the embryo usually consists of 50 cells. Development After implantation A blastocele is a small cavity on the center of the embryo, and the developing embryonary cells will grow around it. Then, a flat layer cell forms on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most animals and some plants. Differences may include secondary sex characteristics, size, weight, colour, markings, or behavioural or cognitive traits. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is ''monomorphism'', which is when both biological sexes are phenotypically indistinguishable from each other. Overview Ornamentation and coloration Common and easily identified types of dimorphism consist of ornamentation and coloration, though not always apparent. A difference in coloration of sexes within a given species is called sexual dichromatism, which is commonly seen in many species of birds and reptiles. Sexual selection leads to the exaggerated dim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polygyny
Polygyny (; from Neoclassical Greek πολυγυνία (); ) is the most common and accepted form of polygamy around the world, entailing the marriage of a man with several women. Incidence Polygyny is more widespread in Africa than in any other continent. Some scholars see the slave trade's impact on the male-to-female sex ratio as a key factor in the emergence and fortification of polygynous practices in regions of Africa. Polygyny is most common in a region known as the "polygamy belt" in West Africa and Central Africa, with the countries estimated to have the highest polygamy prevalence in the world being Burkina Faso, Mali, Gambia, Niger and Nigeria. In the region of sub-Saharan Africa, polygyny is common and deeply rooted in the culture, with 11% of the population of sub-Saharan Africa living in such marriages (25% of the Muslim population and 3% of the Christian population, as of 2019). Polygyny is especially widespread in West Africa, with the countries estimated to h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nile Crocodile
The Nile crocodile (''Crocodylus niloticus'') is a large crocodilian native to freshwater habitats in Africa, where it is present in 26 countries. It is widely distributed throughout sub-Saharan Africa, occurring mostly in the central, eastern, and southern regions of the continent, and lives in different types of aquatic environments such as lakes, rivers, swamps, and marshlands. In West Africa, it occurs along with two other crocodilians. Although capable of living in saline environments, this species is rarely found in saltwater, but occasionally inhabits deltas and brackish lakes. The range of this species once stretched northward throughout the Nile, as far north as the Nile Delta. On average, the adult male Nile crocodile is between in length and weighs including stomach stones. However, specimens exceeding in length and weighing up to have been recorded. It is the largest freshwater predator in Africa, and may be considered the second-largest extant reptile in the w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Martial Eagle
The martial eagle (''Polemaetus bellicosus'') is a large eagle native to sub-Saharan Africa.Ferguson-Lees & Christie, ''Raptors of the World''. Houghton Mifflin Company (2001), . It is the only member of the genus ''Polemaetus''. A species of the booted eagle subfamily (Aquilinae), it has feathering over its tarsus. One of the largest and most powerful species of booted eagle, it is a fairly opportunistic predator that varies its prey selection between mammals, birds and reptiles. It is one of few eagle species known to hunt primarily from a high soar, by stooping on its quarry.Steyn, P. (1983). ''Birds of prey of southern Africa: Their identification and life histories''. Croom Helm, Beckenham (UK). 1983. An inhabitant of wooded belts of otherwise open savanna, this species has shown a precipitous decline in the last few centuries due to a variety of factors. The martial eagle is one of the most persecuted bird species in the world. Due to its habit of taking livestock and re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crowned Eagle
The crowned eagle, also known as the African crowned eagle or the crowned hawk-eagle (''Stephanoaetus coronatus''), is a large bird of prey found in sub-Saharan Africa; in Southern Africa it is restricted to eastern areas.Sinclair & Ryan (2003). ''Birds of Africa south of the Sahara''. Its preferred habitats are principally riparian woodlands and various forests. The crowned eagle is the only extant member of the genus ''Stephanoaetus''. A second species, the Malagasy crowned eagle (''Stephanoaetus mahery'') became extinct after humans settled on Madagascar.Goodman, Steven M. (1994). Proceedings of the Biological Society of Washington 107(3): 421–428 ISSN 0006-324''Description of a new species of subfossil eagle from Madagascar: ''Stephanoaetus'' (Aves: Falconiformes) From The Deposits Of Ampasambazimba''. At least 90 percent of the diet is mammalian; the usual prey taken by populations shows pronounced regional differences. Throughout its range the principal prey items are s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Python Sebae
The Central African rock python (''Python sebae'') is a species of large constrictor snake in the family Pythonidae. The species is native to sub-Saharan Africa. It is one of 11 living species in the genus ''Python''. Africa's largest snake and one of the eight largest snake species in the world (along with the green anaconda, reticulated python, Burmese python, Southern African rock python, Indian python, yellow anaconda and Australian scrub python), specimens may approach or exceed . The southern species is generally smaller than its northern relative but in general, the African Rock Python is regarded as the longest species of snake in the world. The snake is found in a variety of habitats, from forests to near deserts, although usually near sources of water. The snake becomes dormant during the dry season. The Central African rock python kills its prey by constriction and often eats animals up to the size of antelope, occasionally even crocodiles. The snake reproduces by egg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foraging
Foraging is searching for wild food resources. It affects an animal's Fitness (biology), fitness because it plays an important role in an animal's ability to survive and reproduce. Optimal foraging theory, Foraging theory is a branch of behavioral ecology that studies the foraging behavior of animals in response to the environment where the animal lives. Behavioral ecologists use economic models and categories to understand foraging; many of these models are a type of optimal model. Thus foraging theory is discussed in terms of optimizing a payoff from a foraging decision. The payoff for many of these models is the amount of energy an animal receives per unit time, more specifically, the highest ratio of energetic gain to cost while foraging. Foraging theory predicts that the decisions that maximize energy per unit time and thus deliver the highest payoff will be selected for and persist. Key words used to describe foraging behavior include ''resources'', the elements necessary fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Display (zoology)
Display behaviour is a set of ritualized behaviours that enable an animal to communicate to other animals (typically of the same species) about specific stimuli. These ritualized behaviours can be visual however many animals depend on a mixture of visual, audio, tactical and/or chemical signals as well. Evolution has tailored these stereotyped behaviours to allow animals to communicate both conspecifically and interspecifically which allows for a broader connection in different niches in an ecosystem. It is connected to sexual selection and survival of the species in various ways. Typically, display behaviour is used for courtship between two animals and to signal to the female that a viable male is ready to mate. In other instances, species may exhibit territorial display behaviour, in order to preserve a foraging or hunting territory for its family or group. A third form is exhibited by tournament species in which males will fight in order to gain the 'right' to breed. Animals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dry Season
The dry season is a yearly period of low rainfall, especially in the tropics. The weather in the tropics is dominated by the tropical rain belt, which moves from the northern to the southern tropics and back over the course of the year. The temperate counterpart to the tropical dry season is summer or winter. Rain belt The tropical rain belt lies in the southern hemisphere roughly from October to March; during that time the northern tropics have a dry season with sparser precipitation, and days are typically sunny throughout. From April to September, the rain belt lies in the northern hemisphere, and the southern tropics have their dry season. Under the Köppen climate classification, for tropical climates, a dry season month is defined as a month when average precipitation is below . The rain belt reaches roughly as far north as the Tropic of Cancer and as far south as the Tropic of Capricorn. Near these latitudes, there is one wet season and one dry season annually. At the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_in_flight.jpg "Click for more on -> Martial Eagle")
_immature.jpg "Click for more on -> Crowned Eagle")
