Weeping crocodile?
Have you ever seen a crocodile in tears? In fairy tales, crocodiles are often portrayed as cunning and fierce animals, so how can they shed tears for their hunters? Therefore, “crocodile’s tears” are often compared to false compassion or false kindness.
In fact, crocodile tears are not a fairy tale scenario, but a natural phenomenon that occurs in the real world. Many crocodiles living in the Amazon rainforest shed tears of compassion when they leave the water or when they are feeding.
The wisdom behind the tears
Scientists have found that there are several reasons for crocodile tears: First, there is a gland called “Harderian gland” on the transient membrane (third eyelid) of reptiles, which can secrete salt-containing fluid to lubricate the eyes. Due to the long time in the water, when the crocodile leaves the water surface, it will secrete fluid because the eyes are too dry, and it looks like the crocodile is in tears.
Secondly, it is possible that the crocodile’s tears flowed into the eyes because the hot air passed through the sinuses and stimulated the tear glands during the feeding process.
Some studies suggest that crocodiles shed tears to eliminate excess salt. However, tears can help crocodiles eliminate a small amount of salt, but the actual salt-removal organ of crocodiles is the salt-secreting gland on the tongue, which is similar in structure to the salt glands of other birds and marine animals.
Moreover, not all crocodiles shed tears. Some crocodiles only spill a little secretion next to their eyelids, which does not constitute the phenomenon of shed tears.
What! How dare the butterfly on the head of the crocodile?
Yet, the magic of nature is not only that. The tears shed by crocodiles not only moisturize the eyes, but also can be used by other creatures.
Insects will suck the tears of crocodiles. Butterflies, bees and moths have been recorded to suck tears from crocodiles and turtles. This behavior is called “Lachryphagy”, where the insects suck the tears to obtain the minerals and amino acids in them. This is a unique sight in tropical rainforests, where it is difficult for insects to get salts and minerals, although these are important elements for metabolism, growth and reproduction. The tears of crocodiles contain the salts and amino acids needed by insects, which attract butterflies and bees to come and feed on them.
Crocodile Syndrome
In medicine, crocodile tears are also essential. “Brugada syndrome (BrS)” is a disease of eating accompanied by tears, which is also called “crocodile tear syndrome” because it resembles the behavior of crocodile tears during eating. The disease was first discovered by the Russian theologian F. A. Bogorad, after whom it was named.
Brugada syndrome(BrS) is caused by abnormal nerve regeneration in the facial nerve during recovery from Bell’s palsy*. The most common manifestations include unilateral reflex tearing during feeding, though bilateral tearing has also been observed in patients.
*Note: Bell’s palsy is a kind of facial muscle paralysis caused by the dysfunction of facial nerves due to an unknown factor or viral infection that impairs the blood circulation supplying nutrients to the facial nerves.
Currently, clinical treatment consists of blocking the adrenergic receptors in the lacrimal gland with guanethidine solution. Oral treatment with Propantheline bromide has also been attempted. Nonetheless, the side effects of these drugs outweigh their effectiveness and are not the preferred treatment. Alternatively, surgery to remove the lid of the lacrimal gland may be an option.
The most widespread treatment for Brugada syndrome(BrS) is the injection of Botox into the lacrimal gland, which works by blocking the transmission of abnormal parasympathetic fibers affecting the gland, and its effects last about 6 months.
Conclusion
“If that the earth could teem with woman’s tears, Each drop she falls would prove a crocodile.”-Shakespeare’s Othello
In fact, the tears of crocodile already appeared in the 17th century literary records. Nowadays, crocodile tears are no longer a spectacle to us. I believe that as long as you are willing to observe, there are surprises everywhere. This is the end of today’s brief introduction. I hope you can have a better understanding of the small creatures around you, and maybe you will find more small animals with blood and tears like humans!
Do you want to know more about animals? You can click the link below!
References:
- Crocodile tears? Don’t be ridiculous! It’s just lubricant – National Geographic (Chinese) 🔗
- Modi P, Arsiwalla T. Crocodile Tears Syndrome. [Updated 2022 May 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: 🔗
- No Faking It, Crocodile Tears Are Real – Science Daily 🔗
- 封面圖片取自pixabay
