It is 6.15am and I am crouching on the grass in the dark, metres away from a hideout belonging to Singapore's famous Bishan otters.
For the past half-hour, the area has been peaceful, interrupted only by the call of a koel bird, joggers and the occasional vehicle.
But there is excitement in the air because somewhere inside the otters' den, known as a holt, are 16 members of Singapore's largest otter romp. The group ranges from five-month-olds to an adult that is about seven years old.
The otter family is presumably asleep, but should stir any minute. Waiting in the darkness with me are nature enthusiasts Bernard Seah, 50, and Max Khoo, 26, whom I have joined for a morning of otterwatching.
We know we are in the right place because Mr Seah, an amateur wildlife photographer, spotted some clues here during a recce.
"I could see very wet, fresh spraint last night," he says, referring to otter dung. "Like humans, one of them came out in the middle of the night to do its business."
Spraint is a fishy smelling mixture of otter faeces and a jelly-like secretion whose scent helps the creatures mark their territory.
What you can ask your kids when otter-watching
• How many otters can you spot?
• What do you think otters eat?
• How are the otters interacting with one another?
• Why do you think they roll on the grass or sand sometimes?
• Why do you think it might be a bad idea to get too close to the otters?
• What are some of the differences between an otter and monitor lizard when they are swimming?
Minutes later, Mr Seah, who came armed with a head torch and a hand-held flashlight, shines a red light at the area outside the holt, whose location cannot be made public as this might attract poachers.
We spot something - eyeshine, from the first otter out. Minutes later, more gleaming pairs of eyes follow. We hear high-pitched squeaks as the otters "chat" and spraint on the grass.
Then it is time for a dip in the Kallang River and the first catch of the day. The otter family travels together and as they swim, their bodies move up and down in an undulating motion known as periscoping. (Monitor lizards, by contrast, move their tails laterally, or side to side.)
We are hot on their heels. Mr Seah whizzes ahead on his e-scooter, leaving me and Mr Khoo to brisk-walk down paths near the waterway to the creatures.
How to spot otters
• Try your luck at Kallang River and Marina Bay. The Bishan family of otters has a large feeding range which spans these areas. In the same morning, they might be spotted swimming in Whampoa River - a stone's throw from Boon Keng MRT station-as well as the Kallang River near Kallang MRT station, for example.
• Have an early start - before 7am - if you want to spot the otters as they head out to fish.
• A bicycle or an e-scooter might make it easier to keep up with the otters when they swim.
• Wear comfortable shoes, stay hydrated and do not feed the otters or try to touch or chase them. They are wild animals and may bite if they feel threatened.
There are more than 10 smooth-coated otter families in Singapore, in areas such as Sungei Buloh, Pasir Ris, Marina Bay and Changi, where they occupy mangroves, coasts, reservoirs, rivers and canals. The otters on the mainland are smooth-coated, while Pulau Ubin and Pulau Tekong have smooth-coated otters as well as small-clawed ones - the smallest otter species in the world.
Singapore has about 80 smooth-coated otters, also known as Lutrogale perspicillata - one of 13 otter species in the world. The population here is stable, but the species is critically endangered due to shrinking habitats and human disturbance in other countries, says Mr Khoo, a conservation manager at NParks.
Native to Singapore, the species was not seen here between the 1970s and 1990s, but made a comeback in 1998, thanks to an abundance of clean water, fish and naturalised habitats along waterways.
For the next few hours, we follow the otters as they swim along Kallang River and Whampoa River, getting their paws on tilapia, catfish and eel. "No Fishing," says a nearby sign - not that it matters when you are a web-footed carnivore at the top of the food chain.
One otter tries to snatch a fish from another. Others engage in playfighting. Meanwhile, an older otter teaches younger ones to fish. When it gets too tiring to tread water while chomping fish, some otters carry the food to a ledge to eat.
By now - it is 7.15am - they have attracted a captive audience of schoolchildren and residents.
Mr Seah says of the Bishan otters: "If you watch them over a period of time, you notice that each otter has its own character."
One of them is a straggler, for example, and another a fun-loving character that rolls on its back a lot.
"They are also very tightly knit as a family - they help one another," Mr Seah adds. "The (term) is cooperative breeding: When mum and dad have different sets of litter, the older ones look after the younger ones. Just watching that, you gain a lot of respect for the animal."
Mr Seah, who also works as a master of ceremonies, made headlines last year when the Bishan otters photobombed a picture he was taking of a British couple's marriage proposal at Marina Reservoir.
Otters are monogamous. The Bishan family is particularly tight-knit.
The romp's former alpha male, dubbed "Bishan dad" by otter-lovers, made headlines when he died last May at age seven or eight.
But the mother of the family found a new mate soon enough.
"Within 24 hours, a new male tried to jump into the family - he was likely an outsider," Mr Seah says. "Judging from the body language of the rest of the family, they weren't very receptive of him. They kind of chased him away, but it wasn't with full aggression. In about a week, he seemed to be accepted."
Mr Khoo and Mr Seah are members of Otter Working Group, which includes academics, otter enthusiasts and government and non-governmental agencies. Mr Khoo, in particular, is fascinated by how the smooth-coated otters in Singapore have adapted to the urban environment.
Smooth-coated otters in Singapore have resting sites and holts in man-made structures, such as gaps under bridges and urban waterways, according to a paper he co-wrote with National University of Singapore biology lecturer N. Sivasothi.
Mr Khoo adds that these otters are perhaps more used to humans in Singapore than in other countries.
"(Lecturer) Siva would always tell me stories of how he would find otters in the dark in Malaysia... There are many things you have to look out for in the wild. You must not let them smell you - you cannot be (upwind). I guess I have it slightly easier by having the otters right in front of me."
Why are the Bishan otters so popular? Mr Khoo says this family has been closely watched over the past few years, which means people have been able to form a continuous narrative of their escapades.
"People are able to tell a good story - where they were born, how the pups grew up, how they spent their time in Bishan River and moved to Marina Bay, how they interacted and fought battles with other groups to stay dominant."
The Bishan otters, as their name suggests, did not always occupy the Marina territory. They won their stripes after clashing with the Marina otters in savage fights. Their cousins in Sungei Buloh, no less faint of heart, went viral last year after teasing a crocodile.
They have garnered a following. In 2016, the Bishan otters pipped Singlish to win a vote by Straits Times readers for the icon that best represented Singapore. That same year, a retiree jumped into a canal to save a six-week-old pup from drowning after it fell off a ledge.
Still, there are Singaporeans who mistake otters for other semi-aquatic mammals, Mr Khoo says. As we speak, a Kallang resident approaches Mr Seah and asks him if the animals in the water are seals.
Later, trailing the otters, we arrive at a grassy area next to Whampoa River where the otters have resumed their fish-catching and feasting.
In a sudden burst of enthusiasm, they climb up the embankment, race past us and roll around on the grass, the river water spraying off their shiny bodies in the rising sun. They do this to maintain the insulating properties of their fur.
We shadow the creatures, excited to get a closer view. Perhaps a little too excited - later, Mr Khoo informs me I have stepped in a mound of fresh spraint.
About an hour later, when the otters swim downriver, we find a monitor lizard on a concrete platform near the water. The alert otters scamper up the grassy embankment and start squeaking. Several minutes later, they are no longer bothered and start to roll around.
"The monitor lizard felt they were a threat and it was swinging its tail, but the otters were just curious," says Mr Seah.
We were lucky to encounter the otters that day, but it can take hours to spot a wild otter - if at all. Unsurprising, given how the Bishan otters have a feeding range of around 12km, along the Kallang River from Bishan to Marina Barrage.
"People think, 'If I go to Bishan or Marina Bay, I can definitely see them," says Mr Khoo. "But you have to put in the legwork and effort to travel around and find them."
After 10am, the otters have swum farther south and scampered up and off an embankment on the other side of the river.
Later, they will have a siesta, fish again in the afternoon and maybe even swim to Kallang Wave Mall before bedtime at around 7pm.
For us humans, it has been a rejuvenating morning of otter therapy.
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