Why bat an eyelid at Batagur? Batagur’s the Best Beast Because....

Aside from having a completely made-up name* which sounds tough like a boxing dog's growl,  what is so outstanding about this group of turtles of the genus Batagur? I know I'm not the only one that thinks they're wonderful, they have a set of characteristics which make them remarkable to anyone. Firstly, their physical attributes make them impressive, to herpetologist and lay person alike. Aside from being physically spectacular, biological studies have shown Batagur turtles to display some marvelous adaptations to their lifestyle. Lastly, their chosen ecosystems and attributes of their tissues and eggs have made them of conservation interest, leading them to dubious distinction of being among the most represented genera of turtles threatened with extinction. 

Dr Shailendra Singh, one of India's leading conservationists is a fan: "I like all large river turtles, and Batagur is my favorite genus of them.  Males in nuptial colors are unmatched! I believe Batagur needs a lot of our support to survive well into future. Of the genus, the Painted Terrapin (Batagur borneoensis), is my favorite turtle." (Gray, 2017). 

To look at, your average female Batagur is gorgeous in her olive-brown colouring and impressive size: they can get over 60cm in shell length and over 30kg. 

Batagur turtles are biologically very interesting. Several species of Batagur inhabit estuaries (See Table below), where salt water mixes with freshwater and concentrations can vary from completely fresh to the same concentration as sea water. They have been found happily swimming out to sea but have no physiological way to deal with the salt water, unlike sea turtles with their salt glands. Estuaries are a challenging place to live but those animals with the ability to cope are rewarded with the high fertility. 

These estuary dwellers cope with salt water my means of their relatively impermeable skin, adjusting drinking behaviour, and the output of their kidneys. Studies have found that estuarine Batagur will stop drinking water when placed in sea water and can survive in it for up to two weeks (Dunson and Moll, 1980). Kidney output will also shut down when the animal is in sea water, retaining the maximum water in their system until such a time that they encounter fresh water to drink. 

Table: Batagur species classified according to their habitat 

Estuary dwellers	River Dwellers
B. affinis (Cambodia, Malaysia, Thailand, Singapore, Indonesia)	B. dhongoka (India)
B. baska (India, Bangladesh, Myanmar)	B. kachuga (India)
B. borneoensis (Indonesia, Malaysia)	B. trivittata (Myanmar)

 

Batagurs have sturdy shells. Yes, turtle shells are generally quite solid but Batagurs, females in particular, take it to the next level. Female Batagur are on average larger than males, to allow them to contain the large mass of eggs upon laying. While they are still strong and swift swimmers, this does limit their speed and ability to evade such predators as estuarine crocodiles. In much of their range, they also cohabit with Tigers, which females may encounter when they come onto land to nest. The shell of a Batagur can reach several centimeters thick and possesses thick reinforcing buttresses about the shell openings. The reinforcement that this creates aids the turtles ability to withstand the crushing forces of some of the most impressive predators around.  

Withstanding the pestering and attacks of smaller, more agile carnivores, is another matter. I have spoken to fishermen that report otters in their river system in Cambodia harassing and injuring large Batagurs and even removing the turtles’ feet.  

 

 

But how does this stack up against other animals deemed by experts to be number 1? 

Steve Platt has done a lot of work on Batagur and other varied species throughout the Americas and Asia but his interests as a naturalist are varied. I was sure that he would agree that Batagur was the best, but Morelet’s crocodile, Crocodylus moreletii was his selection.  
"...I'd say Morelets crocodile because I studied them for my dissertation.... Crocodilians in general have always held me spell bound. Large (most of them) apex aquatic predators that live in fascinating habitats (wetlands).” 

Some herpetologists who have had little or no contact with Batagur understandably choose other species as their stand-out species. Tim McCormack cites Cuora mouhotii as the coolest species, mainly as he spent a lot of time studying them and getting to know their behaviour and their very individual personalities intimately. McCormack also says he likes underdogs, perhaps meaning that these are cool because they’re not cool? Their individual personalities were also pointed out by Doug Hendrie, who founded the turtle rescue centre in Cuc Phuong, Vietnam (as well as being a leader in turtle conservation in the region). As they are native to the area, they were some of the first animals in the centre. While all of the turtles in the centre had individual numbers within their species, C. mouhotii were also identified by names as they displayed such individuality. 
Lonnie McCaskill is a herpetologist that has worked throughout the world. He thinks the Cane turtle, Vijayachelys silvatica is the coolest as it’s relatively unknown. It also stands out to him as it’s an endemic that has a limited habitat, specialised diet, and small niche. Indeed, after their discovery and description of two animals in 1912, it was seventy years until another was seen.  

Other herpetologists don’t even consider their study animal the coolest! For one, Dr Kate Hodges completed her PhD on the Broad-shelled longneck turtle, Chelodina expansa extensively but the animals that blow her mind are the velvet worms (Onychophora) due to their unlikely predatory habits and the awesome glue that they shoot. 

Dr Anna MacDonald is the Project Manager of the Oz Mammals Genomics Initiative, among other things, and has named bandicoots as the cream of the crop. While Dr MacDonald is a genomics expert who has conducted field and lab work with many mammal species, she cited the bandicoot’s digging prowess that makes them ecosystem engineers and also their undisputed cuteness: 

“Bandicoots [are the coolest] because they’re tiny little digging ecosystem engineers and also they’re very bandicute!” 

So, while many would disagree with me, claiming that Velvet worms, Bandicoots, or Morelet’s crocodile is the coolest species, it is my subjective truth that Batagur are the coolest of all organisms. Batagur, with sufficient populations, will nest en masse and still disguise their nests well with their plastra (lower shell). They will plunge into sea water although they’re not particularly specialized for that medium. They happily live in the fresh water and evidence is emerging that they come onto land more than was previously thought. Adults can withstand the bite of some of the strongest jaws in the world. They are beautiful, resilient, tasty, and have been brought to extremely low population levels by the actions of humans but still bewitch and amaze.
    
    

*Batagur has no known etymology but appears to have been created on a whim by J. E. Gray. 

Sources:

• Davenport, J. & Wong, T. M. 1986. Observations on the water economy of the estuarine turtles Batagur baska (Gray) and Callagur borneoensis (Schlegel and Muller). Comparative Biochemistry and Physiology 84: 703–707.
• Dunson, W. A. and E. O. Moll. 1980. Osmoregulation in sea water of hatchling Emydid turtles, Callagur borneoensis, from a Malaysian Sea Beach. Journal of Herpetology 14(1): 31-36.  
• Gray, J. 2017. Faces of the TSA vol 4. Dr Shailendra                                                                 Singh. http://turtlesurvival.nonprofitsoapbox.com/blog?start=80#.XyIoqp4zY2w.            accessed 30/7/20

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