Tears for a crocodile

Abstract

In October 2015, I made the acquaintance of a lonesome crocodile living in a small river in Khao Yai National Park, Thailand. When we met, it was doing some very serious resting (Figure 1). So deep did its slumber seem that you might have been forgiven for believing you could walk right up to it without it ever knowing. I decided to keep a safe distance, however, having heard that crocodiles might be unihemispheric sleepers, and therefore might “keep one eye open” when they take a siesta! Moreover, although its eyes seemed to shed no tears, I was not about to trust in the old idea that a crocodile who wants to eat you weeps before striking. And I'm pretty certain I would not have been persuaded to decide differently had I known at the time that some actually might… A Burton The idea that crocodiles cry in order to catch sympathetic humans goes back a long way. For example, in 1590, in his epic poem The Faerie Queene, Edmund Spenser tells us that the crocodile weeps woeful, tender tears in order to lure and gobble up anyone so foolish as to be taken in and offer consolation. And during a (damningly slave-trading) voyage to the Caribbean in 1565, commanded by Sir John Hawkins, gentleman adventurer John Sparke recorded that whenever the local crocodiles were hungry they would cry and sob “like a Christian body” to provoke the approach of unwary comforters, and then snatch them up – see Richard Hakluyt's 1589 collative work republished in The Principal Navigations, Voyages, Traffiques and Discoveries of the English Nation, Volume XV (1890; Edinburgh: E & G Goldsmid). In earlier times, however, it was thought that crocodiles only cried after they grabbed you. In his 13th-century work De proprietatibus rerum, Franciscan monk Bartholomaeus Anglicus noted an ancient belief that if a crocodile came upon someone at the water's edge it would certainly try to catch him, but would weep over his dead body before tucking in. And around 400 CE, St Asterius wrote that a crocodile weeps when all that is left is his victim's bony head, but only because his meal is finished – see Ad Vingerhoets’ Why Only Humans Weep: Unravelling the Mysteries of Tears (2013; Oxford, UK: Oxford University Press). But while “crocodile tears” forever became a metaphor for hypocrisy, by the early 1700s the idea that crocodiles actually cried was already fading, and in 1924 it was roundly declared a myth during a reading of George Lindsay Johnson's ophthalmological research at the Royal Society in London (doi.org/10.1098/rstb.1927.0007). And yet, by the time I met my crocodile, scientists had, unbeknownst to me, reported the filming of captive crocodilians indeed producing lunchtime tears (BioScience 2007; 57: 615–17)! Of the two common caimans (Caiman crocodilus), two Yacare caimans (Caiman yacare), and three American alligators (Alligator mississippiensis) examined, all but one Yacare and one common caiman produced moisture and even bubbles in their eyes just before, during, or after they ate. Upon learning this in 2020, I turned quickly to the internet and watched loads of close-up videos of crocodilians in rivers, lakes, and ponds, or on their banks, doing dinner. There was even excellent footage of my very own Khao Yai crocodile munching on a deer (https://bit.ly/35PGOOS). But for the life of me I could see no tears. When I consulted crocodile expert Adam Britton (Charles Darwin University; Darwin, Australia) he confirmed that these secretions are indeed produced, but he pointed out that the animals in the BioScience paper were all fed on dry land, and that “if the crocodile has a wet head, typically if it's in the water or at the water's edge, you wouldn't see [tears] at all”. There was my problem. But since we normally see crocs around water, this raises an interesting question: without film or magnifying technology, how on Earth did observers who lived hundreds of years ago notice this phenomenon? My reading rekindled my interest in that lone Thai crocodile, and in its enigmatic history. No one knows where it came from; no crocodiles had previously been recorded in the park. Did it get there itself or did someone drop it off in the river? No one knew its sex either – determinations usually require an internal examination. Even its species was a mystery since no one ever found any scats for DNA analysis. After making some inquiries, however, I received a kind letter from Ronglarp Sukmasuang of Kasetsart University (Bangkok, Thailand) whose conservation work includes crocodile reintroductions, and he assured me that his colleague Panya Yongprapakorn had confirmed it to be a male Siamese crocodile (Crocodylus siamensis), a very rare creature indeed. Only some 500 may be left across Southeast Asia. Sadly, he also told me that he had not seen the animal for a very long time, adding heart-rending weight to rumors I had read about its death. I felt a little tear welling up. Adrian Burton