Aves or Birds is just one of the classes of the bigger Kingdom Animalia . The birds share some characteristics with another closely related class – Reptiles
Birds are vertebrates – they have an inner skeleton that contains a spine , limbs , and a skull ; Birds are endothermic – they maintain constant body temperature by themselves, without depending on outside factors; Birds are bipedal (i.e., they move on two limbs when they are on the ground); The upper limbs of birds have evolved into specialized structures – wings, that allow flight; The body of the most bird is spindle-shaped (to make the flight more comfortable and more effective); The birds’ bones are hollow inside to lower the overall weight of the body; The body is covered with unique structures – feathers . Only legs are covered with scales ; The birds have a heart with 4 chambers – this way, the oxygen-rich and oxygen-poor blood is divided correctly, which helps with maintaining constant temperatures The birds have a complex nervous system There are two sexes in birds: male and female ; Fertilization in birds is internal. As a result of fertilization, a closed-off, waterproof egg is formed. The eggs develop outside the body, usually under the care of both parents or sometimes only one. If we want to define birds strictly, we would say they are warm-blooded, bipedal vertebrate animals with forelimbs evolved into wings, covered in feathers, and with a beak instead of a mouth.
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Most birds diet on insects, seeds, flowers, berries, while others (large birds) feed on mammals & reptiles. Find what do birds eat by types.
