Expert: Jonathan Wright - 4/9/2006

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Dear Questioner

Thanks for your questions.

Your first question is quite controversial. Many people believe that humans are the only animals to show emotions such as sadness, but many scientists believe that other animals show these emotions. There are many cases of Indian elephants crying and producing salt tears, as do humans. Jeffrey Masson and Susan McCarthy wrote ‘When Elephants Weep', which mentions several accounts of animals showing various emotions.

http://www.animalsvoice.com/PAGES/writes/editorial/essays/aniemot/lambert_elepha... mentions elephants crying and showing other emotions.

http://www.asa.org.za/animals/info/causes/entertainment/babyelephants/elephantdi... says that elephants cry salt water tears when they are under severe stress. Elephant keepers told Charles Darwin that their elephants shed tears.

http://www.aquaticape.org/tears.html discusses Elaine Morgan's aquatic ape theory. This is the idea that humans went through an aquatic phase in their evolution. Many scientists also believe that elephants went through a similar phase and that shedding salt tears is a way of balancing the concentration of salt within the body. The website says that the lachrymal glands cannot concentrate enough sodium in order to excrete it. It seems that sodium occurs at the same level in tears as in plasma, but the concentration of potassium is 4 times higher in tears as it is in plasma and the manganese concentration may be 30 times higher in emotional tears as it is in plasma. Emotional tears may contain a higher concentration of protein than is found in irritant tears. Crying may help to eliminate prolactin, ACTH, Leucine-Encephalin and manganese.

Florence Lambert (http://members.aol.com/nonverbal3/cry.htm) says that William Frey discovered that emotional tears contain the neurotransmitters leucine-enkephalin (this is an endorphin or natural opiate-like substance used to relive pain) and prolactin (which the pituitary glands releases when the animal is in emotional stress). The site suggests that tears may help the body to alleviate stress and to cleanse itself of toxins.

http://www.wisegeek.com/do-animals-cry.htm says that most vertebrates can produce tears to keep their eyes healthy. The lachrymal system contains tissues that make water, including tears. Land mammals evolved tears to replace the water surrounding the eyes of aquatic animals. Tears clean dirt away from the cornea and keep it moist. Tears contain high levels of nutrients and their anti-bacterial properties help to fight infections. The salt in tears helps create an osmotic balance within the eye.

I'm sorry if this is somewhat confusing, but I've tried to strike a balance between the lobby that elephants only cry because their eyes are irritated and those people who say that elephants cry because they are expressing their emotions. Whatever the situation, elephants shed tears due to the stimulation of the lachrymal glands to secrete water. Tears are used to cleanse the eye and/or to release various chemicals to benefit the elephant.

Your second question is much simpler. Elephants eat grass, as well as edible parts of trees and shrubs, including leaves, fruits, flower buds and the woody branches, roots and bark. African elephants prefer eating grass in the rainy season, but also eat herbs and fruit. Asian elephants eat mostly bamboos and other grasses, palms, fruit, stems, climbers and other forest plants. They may eat bananas, paddy, sugar cane and other cultivated crops.

I hope this helps.

All the best

Jonathan