Birds and reptiles cry similar tears to humans, says new research

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Birds and reptiles cry similar tears to humans, says new research

A researcher collects tears from a turquoise-fronted amazon. Although the tears of mammals like dogs and horses are more similar to humans, there are

 

similar amounts of electrolyte fluid in the tears or birds, reptiles and humans.

 

Birds and reptiles may not resemble humans in many ways, but they cry similar tears.

The composition of human tears is well known, but until now, there was very little research into the composition and structures of tears in reptiles,

 

birds and other mammals.

 

 

A researcher collects tears from a broad-snouted caiman. The team collected tears from captive animals in conservation centers around the world in

 

the least stressful way possible.

 

That lack of research could be considered a crying shame since understanding the makeup of various species' tears can give insight into better eye

 

treatments for both people and animals, as well as improve our understanding of animals' evolutionary adaptations, according to a new study in

 

Frontiers in Veterinary Science.

Researchers in Brazil collected samples of healthy animals' tears from seven species of birds and reptiles, including macaws, hawks, owls and parrots,

 

as well as tortoises, caimans and sea turtles.

 

"It's important to understand healthy animals in order to treat sick animals, because species depend on their vision," said lead study author Arianne

 

Oriá, a professor of clinical veterinary medicine at the Federal University of Bahia in Salvador, Brazil. "Animals are not able to live without vision in the

 

wild. A sea turtle without vision will die."

Humans also need to have what researchers call a healthy "ocular surface" -- the outer layer of the eye, including the cornea, the tears and the edges of

 

the eyelids. Otherwise they will have a lot of discomfort, redness and itching, or possibly even more severe vision problems.

 

The new study found both similarities and differences to human tears that could be key to veterinary treatments and eye disease. Although the tears of

 

mammals like dogs and horses are more similar to humans, there are similar amounts of electrolyte fluid in the tears of birds, reptiles and humans

 

(but birds and reptiles had slightly higher concentrations than humans).

 

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