Yahoo Search Busca da Web

  1. Cerca de 17.600 resultados de busca

  1. › wiki › MammalMammal - Wikipedia

    Há 4 dias · A mammal (from Latin mamma 'breast') is a vertebrate animal of the class Mammalia (/ m ə ˈ m eɪ l i. ə /). Mammals are characterized by the presence of milk-producing mammary glands for feeding their young, a neocortex region of the brain, fur or hair , and three middle ear bones .

    • Mammals

      A mammal (from Latin mamma 'breast') is a vertebrate animal...

    • Main Characteristics
    • Main Groups
    • Modes of Life
    • Taxonomy
    • Debate on The Meaning of "Mammalia"
    • Gallery

    Reproductive cycle

    Most marsupial and eutherian mammals have a reproductive cycle known as the oestrous cycle (U.S: estrous cycle). Females are sexually active only during the oestrous stage, when they are 'on heat' for a few days each month. If an ovum is not fertilized, the endometrium (uteruslining) is resorbed. Oestrus cycles may occur once or twice a year, or many times a year. Each group of mammals has its own frequency. Humans and primates, are quite different. They have a menstrual cycle. In this case,...


    One diagnostic feature of mammals is the lower jaw. Unlike earlier forms, it is a single bone, the dentary. This is one feature which can be seen in fossils, or at least those which are complete enough to have the lower jaw. Another diagnostic feature is the ear ossicles. Mammals have three little bones in their inner ear. These ear ossicles are bones which were, long ago, part of the lower jaw in early proto-mammals. There are quite a number of other features in the skull and limbs, so that...

    Neocortex and behavior

    Another diagnostic feature is the neocortex of the brain, which no other vertebrate has. This is involved in the kind of flexible behavior and learning typical of mammals. Reptiles and birds have much of their behavior controlled by "inherited behavior chains", which roughly translates as "instincts". Almost all animals can do some learning, but mammals do far more than other vertebrates. Their behavior is much more flexible than lizards, for example, and that is made possible by their neocor...

    All mammals feed milk to their young, and protect and look after them. The vast majority of mammal species give birth to live young, these are the placental mammals, most of which are classified as Eutheria and a small number are classified as marsupials. Marsupials are mammals with pouches to carry young in, like the kangaroo. There are only five ...

    By number of species, mammals (with 5488 species), are not the most successful vertebrates. Birds, with about 10,000 species have nearly twice as many, and reptiles have just as many as birds.Fish have even more species. There are 27,000 species of fish, of which nearly 26,000 are bony fish. Despite this, many zoologists do regard mammals as a succ...

    The evolutionary relationships among land vertebrates is as follows: 1. Tetrapoda (land vertebrates) 1.1. Amphibia(lay eggs in water) 1.2. Amniota (lay cleidoic eggs) 1.2.1. Sauropsida (all true 'reptiles') 1.2.2. Synapsida (all 'mammal-like amniotes') Pelycosauria Therapsida (in particular, the Cynodontia) Mammalia(bea...

    Because two quite different dates are given in the taxobox, an explanation is needed. Rowe defines mammals as "the taxon originating with the most recent common ancestor of extant (living) Monotremata and Theria". That puts the emphasis heavily on living mammals, where, as Rowe points out, the database of characters is extensive. Kemp explains the ...

  2. › wiki › DolphinDolphin - Wikipedia

    Há 1 dia · Dolphin. A common bottlenose dolphin ( Tursiops truncatus) A dolphin is an aquatic mammal within the infraorder Cetacea. Dolphin species belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins ), Iniidae (the New World river dolphins), Pontoporiidae (the brackish dolphins), and possibly ...

  3. › wiki › ElephantElephant - Wikipedia

    Há 1 dia · Elephants are the largest living land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are the only surviving members of the family Elephantidae and the order Proboscidea; extinct relatives include mammoths and mastodons.

  4. 6 de ago. de 2023 · mammal, (class Mammalia), any member of the group of vertebrate animals in which the young are nourished with milk from special mammary glands of the mother. In addition to these characteristic milk glands, mammals are distinguished by several other unique features.

    • Mammal wikipedia1
    • Mammal wikipedia2
    • Mammal wikipedia3
    • Mammal wikipedia4
    • Mammal wikipedia5
  5. › wiki › CatCat - Wikipedia

    Há 1 dia · The cat (Felis catus) is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of the family.