The excitement amongst the students was almost palpable on that bracing winter morning.
Our time for the class nature trip was almost coming to an end, but this day was going to feature our final stop — a captivating destination by all accounts — that promised close glimpses of the wild that many of us had only hitherto read in books or perhaps seen in nature documentaries on television.
The previous night, we — a gaggle of nearly 50 teenaged boys from a boarding school, three supervising teachers, and two hostel wardens — had a gathering during which we were told a little bit of what we could expect at the destination, which was revealed to be the Bhagabatpur Crocodile Sanctuary, the only crocodile conservation project in our state of West Bengal in East India.
Located on the banks of the tidal estuarine river Saptamukhi, the sanctuary at Bhagabatpur is a part of the UNESCO World Heritage Site Sundarban National Park, the magnificent mangrove forest-rich area at the Ganges delta upon the Bay of Bengal. Sundarban (pronounced soonder-, meaning beautiful, and -bun, meaning forest) represents an active delta and unique coastal ecosystem, home to diverse flora and fauna, including birds, aquatic animals, and reptiles. Many of its inhabitants, considered endangered, have been included in the International Union for Conservation of Nature and Natural Resources (IUCN) Red List of Threatened Species.
Thanks to conservation efforts by a variety of stakeholders such as the Bhagabatpur Sanctuary, saltwater crocodile numbers have rebounded so significantly that IUCN has moved their conservation status to “least concern”.
Two crocodilian varieties found in South Asia, the vulnerable Mugger or Marsh crocodile (Crocodylus palustris) and the critically endangered Gharial (Gavialis gangeticus), are currently considered under threat due to habitat loss and illegal killing for their skin. The saltwater crocodile (Crocodylus porosus), which typically inhabit inland lakes, brackish mangrove swamps, and marshes, as well as coastal and tidal areas of rivers, was once also considered endangered in the eighties. Thanks to conservation efforts by a variety of stakeholders such as the Bhagabatpur Sanctuary, their numbers have rebounded so significantly that IUCN has moved their conservation status to “least concern.” Saltwater crocodiles are large, heavy reptiles; males grow up to 20 feet and can exceed 2000 pounds while females are half as long but only a fourth or fifth in weight. They are the apex predators of their habitat; they eat everything they can grab with their cavernous mouths and sharp, peg-like teeth— varieties of fish, crustaceans, other reptiles, birds, and even mammals like monkeys, deer, water buffalo, and humans if such prey is unfortunate enough to be close by and unaware.
Imagine the effect that information had on our impressionable young minds! It was terrifying and we couldn’t wait to witness these aquatic carnivores in all their glory.
Right after our early morning ablutions, we were picked up in separate transport vehicles and brought to the Namkhana ferry station. At that time, the State-run ferry service used to run between Namkhana and Bhagabatpur Sanctuary only once a day, leaving the jetty at 7:30 in the morning and returning by early afternoon. Thankfully, our school authorities had made prior arrangements; we piled on to a couple of rented motor launches and were merrily on our way cutting through tranquil riverine waters. It would take us about two and a half hours to reach, and we were already famished: floating on river water with high salinity content perhaps has that effect on people? Who knows. But we were promised a hot mid-morning lunch once we reached our destination.
Upon disembarking from the launch at the sanctuary stop, we walked up a paved, stepped landing onto dry land. Some of those steps are likely submerged when the tide comes in because there was green, mossy outgrowth on the ones closer to the water; also, on both sides of the landing, there were these uniformly thick, grey, muddy sedimentary deposits that are peculiar to the coastal wetlands of this area. I spied some small crustaceans burrowing themselves in the mud; they could have been mud crabs or shrimps, but before I could get a closer look, I succumbed to pangs of hunger and ran up—for lunch had been announced.
The Bhagabatpur Crocodile Project was initiated in 1976 as an effort to preserve the saltwater crocodiles of South Asia in the unique ecosystem of the Sundarbans. In conjunction with governmental authorities and experts from other parts of the world, the program aimed to train staff members on techniques of capturing and releasing crocodiles, as well as collecting crocodile eggs to nurture them under more hospitable conditions. Staff members were also tasked to conduct a periodic census of the estuarine crocodile populations and teach residents of the same habitat as these predators how to avoid being caught and eaten.
Saltwater crocodiles, we learned, are strong swimmers. Their eyes, ears, and nostrils, placed high on their flat head and elongated snout, are perfectly positioned to remain over the water surface as they remain submerged, and their airway anatomy and lungs allow them to remain underwater holding their breath for up to nearly two hours—which helps them ambush their prey stealthily. Operating in land, air, or water, they swallow small prey whole; larger victims are either dragged into the water and drowned or crushed. To tear off manageable chunks of meat from large prey, they bite into the flesh and do a whole-body spin, appropriately known as a “death roll.” Like vultures on land, these crocodiles are perfectly content to scavenge on carcasses of dead animals, thereby keeping the rivers clean. They also have no qualms about swimming out to the salty sea and snatching marine animals, such as sea turtles and small sharks, if they fancy an occasional munch. How do they withstand the increased salinity of seawater? It appears that around their eyes, these ‘salties’ conveniently have specialized salt glands which are capable of excreting the excess salt with their tears. I had chortled: crocodile tears, anyone?!
Saltwater crocodiles have extremely strong jaw muscles to chomp down on food; aided by a second jaw joint, one snap of their jaw can produce an impressive 16,000 Newtons of force. (In case you were wondering, the human jaw generates about 1,300 Newtons.) Interestingly, their muscles to open the jaw are small and weak. The project staff, conservationists, and veterinarians take advantage of this fortuitous fact to securely shut the jaws with rope or sticky tape, or press down with hands, whenever they want to move these reptiles or treat them for medical conditions.
In the hot tropical summers, saltwater crocodiles must remain underwater or skulk under shade; in the winter, they emerge from the water and bask in the warmth of sunlight—which was an additional reason for our class trip to Bhagabatpur being arranged in cooler weather.
Like other reptiles, these crocodiles are cold-blooded or “poikilothermic” animals, incapable of regulating their own body temperatures in absence of an external heat source. In the hot tropical summers, they must remain underwater or skulk under shade; in the winter, they emerge from the water and bask in the warmth of sunlight—which was an additional reason for our class trip to Bhagabatpur being arranged in cooler weather. The external temperatures have further significance for the crocodiles. In early summer, female crocodiles make nests using dry leaves, branches, in addition to grass, and lay eggs inside, where those incubate for about 90 days before hatching. The gender of the hatchling depends on the temperature at which the eggs are incubating; male croc babies only hatch between a sweet spot of 30–32.5 degrees Celsius!
At the sanctuary, the authorities had been worried about downward trends in annual crocodile births due to natural, environmental hazards to the eggs, as well as the maintenance of a healthy ratio of male and female crocodiles. This concern led to the genesis of an artificial breeding program, in which trained project personnel collect the laid eggs after methodically testing the temperature of the nest, replicate the same conditions in enclosed spaces and leave the eggs inside.
Around 2013—I found out years later—the sanctuary had run into a spot of trouble, with higher than usual hatchling deaths in the breeding program. The Forest Department of the state of West Bengal, which has administrative authority over the Sunderbans, had called in a team of experts to advise on the creation of an ideal hatching environment and the use of modern scientific techniques to improve the survival of crocodile hatchlings.
These experts trained project personnel in the field for a year, and by early 2015, the hatchling survival had gone up to around seven out of every ten eggs. The sanctuary was also able to release nearly 75 adolescent crocs into the wild. Nonetheless, Anirban Chaudhuri, a wildlife consultant in herpetology and one of the experts, had voiced concerns about the future. “Since global warming is resulting in an increase of temperature, maintaining the sex ratio of crocodiles is a challenge for us,” Chaudhuri told the Indian daily The Hindu at that time.
“Since global warming is resulting in an increase of temperature, maintaining the sex ratio of crocodiles is a challenge for us.” — Anirban Chaudhuri, a wildlife consultant in herpetology
The timing of our visit wasn’t appropriate to witness the hatchings, but the sanctuary guides, who were showing us around in small groups, took us to see photos they had taken using croc cams, closed-circuit outdoor cameras strategically placed to follow the movements of the reptiles. The guides described how, close to the hatching time, the babies make a “croc-croc” noise to call the mother from inside the eggs; how the personnel assists the hatching by breaking open the partially cracked shells; how the hatchlings derive nutrition for a week from yolk material they ingest during the emergence; and how they are hand-fed with minnows and insects until such time as they are able to grab their food on their own.
The enclosed hatcheries were not open to visitors at that time, but we caught glimpses of the inside through a window that prominently featured crocodile eggs collected by the project personnel to be hatched in carefully controlled environments.
Hatchlings are fed crabs, shrimp, or fish once every other day. The sanctuary maintains a separate open-air enclosure for young crocs for each of their first four years in life. Young crocs usually get a fish-based diet, and the older crocs are treated to meat or chicken once a week. By the time they are about four years old, crocs are safely released in the river far away from localities; the number can vary from tens to hundreds, depending on how many eggs successfully survive the incubation, hatching, and growth.
It was afternoon and time for us to wrap up the day’s trip. On the way out, we were brought to an enclosed area where the wall reached chest height. We peeked in to find a deeper area surrounding a pool of muddy water of uncertain depth, where a sloped embankment, containing the same grey mud we had seen on our way in, gradually receded into the water. The embankment was sparsely littered with what seemed, from our distance, to be young crocs, pale yellow with dark stripes and spots, lazing around taking in the afternoon sun.
Some of us noticed an object that appeared to be embedded in the mud, halfway between the enclosing wall and the water’s edge; it was caked in mud and vaguely shaped like a crocodile—although we couldn’t tell how long—with the familiar dark, scaly, pock-marked appearance from what we could make out. It even had an extended angular end pointing towards us with a crenelated presentation. We decided it must be a tree trunk of some sort, sculpted into a rough crocodilian shape as a showpiece for the croc pool, and were all properly impressed.
About ten feet ahead of us, a classmate got overenthusiastic. The walls of all the enclosures carry warnings painted in big bold letters at regular intervals, urging visitors not to lean over the wall, throw rocks, or poke at the crocs. My smart friend, completely ignoring the words of caution, did exactly that. He tried to lean over the wall and poke at the structure with a long tree branch he had picked up nearby.
In the next few seconds, several things transpired. With a blood-curdling yell, a sanctuary guide, who happened to be close by, yanked our guy out from the wall’s vicinity with such force that the latter fell. The man looked terribly angry. “Have you taken leave of your senses?” he shouted. “Do you have any idea what was about to happen?”
Within a fraction of a second, the trunk came alive. The tail whipped against the mud providing a fulcrum on which the rest of the body pivoted, a huge maw opened and caught the stone in mid-air, and then the entire body glided down into the water with barely a splash.
As the rest of us, including the teachers, made a beeline for the scene of some unknown crime, we were confused about the whole affair. When we gathered around, the man, still visibly upset, picked up a smallish boulder — about the size of a Cornish hen — and commanded: “Watch!” He tossed the stone in the air over the tail-like end of the tree trunk we were admiring. Within a fraction of a second, the trunk came alive. The tail whipped against the mud providing a fulcrum on which the rest of the body pivoted, a huge maw opened and caught the stone in mid-air, and then the entire body glided down into the water with barely a splash. All of us trembled at the scene.
“That would have been you,” said the guide.
This may have been a fully adult saltwater crocodile nearing its date of release — perhaps a little older than the three-year-old whippersnappers who were placed in the same enclosure? I don’t know. But ordinarily lethargic, the crocs are capable of extreme agility and explosive bursts of speed when hunting prey.
None of us spoke much as we filed out of the Bhagabatpur crocodile sanctuary’s gates onto the launches waiting at the jetty. As the riverbank started to fade away, leaving our senses saturated with the burbling of brackish water around the motor launch and the steady hum of its engine, we were probably happy and a whole lot relieved to put some distance between our scared little hearts and the call of the wild.