From an anatomical point of view, we’re pretty different from birds and reptiles, but it turns out that our tears share remarkable similarities.
Tears are not simply made up of water, but contain other substances like sodium, calcium, urea, chloride and proteins. While tears play an important role in eye health, until now they had only been analysed in a few mammal species. A team led by Prof Arianne Oriá, from Brazil’s Federal University of Bahia, wanted to get a better picture of how tears work in other animals, so they studied various reptile and bird species, including macaws, owls, hawks, a type of parrot, caimans, tortoises and sea turtles.
“Although birds and reptiles have different structures that are responsible for tear production, some components of this fluid are present…