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Tears are an important protection and lubricant for the eye. They can flush out irritants and keep the eye wet to enhance vision. The eye's lacrimal system evolved to keep the eye surface moist. In aquatic animals, the eye is constantly bathed in water, but land animals are surrounded by air, so their eyes needed a built-in watering system. While most vertebrates are physically capable of producing tears, many scientists say that humans are the only animals that cry emotional tears. Different sources suggest that chimpanzees, elephants, dogs, and bears can shed tears. But we
couldn't find any scientific studies of animal's emotional tears. As Tom Lutz author of Crying: The Natural and Cultural History of Tears notes, it would be impossible to discern if animal tears were purely emotional or caused by eye irritation. However, if you don't consider tears essential to crying, then many animals cry. Studies have found that very young mammals and birds vocalize when they are separated from their mothers. Baby animals can be quite expressive in their distress at being apart from their primary caretakers. Wildlife experts and hunters
both note that the cry of a bear cub separated from its mother sounds very much like a human baby's cry. While these cries don't include tears, they seem to have an emotional element. And despite the old saying, crocodiles don't shed tears.
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