A smooth-coated otter grabs its 6-week-old pup in its mouth after swimming practise in a storm drain near Singapore River on Jan. 10, 2019. This family of smooth-coated otters, comprising of three adults and three otter pups, made their home in urban city centre of Singapore. (Xinhua/Then Chih Wey)

A family of smooth-coated otters make their way back to their holt after swimming practise near Singapore River on Jan. 10, 2019. This family of smooth-coated otters, comprising of three adults and three otter pups, made their home in urban city centre of Singapore. (Xinhua/Then Chih Wey)

A trio of 6-week-old smooth-coated otter pups learn to swim in a storm drain near Singapore River on Jan. 10, 2019. This family of smooth-coated otters, comprising of three adults and three otter pups, made their home in urban city centre of Singapore. (Xinhua/Then Chih Wey)

A trio of 6-week-old smooth-coated otter pups learn to swim in a storm drain near Singapore River on Jan. 10, 2019. This family of smooth-coated otters, comprising of three adults and three otter pups, made their home in urban city centre of Singapore. (Xinhua/Then Chih Wey)

A family of smooth-coated otters make their way to a canal to practise swimming near Singapore River on Jan. 10, 2019. This family of smooth-coated otters, comprising of three adults and three otter pups, made their home in urban city centre of Singapore. (Xinhua/Then Chih Wey)

A smooth-coated otter grabs its 6-week-old pup in its mouth after swimming practise in a storm drain near Singapore River on Jan. 10, 2019. This family of smooth-coated otters, comprising of three adults and three otter pups, made their home in urban city centre of Singapore. (Xinhua/Then Chih Wey)

A family of smooth-coated otters make their way to a canal to practise swimming near Singapore River on Jan. 10, 2019. This family of smooth-coated otters, comprising of three adults and three otter pups, made their home in urban city centre of Singapore. (Xinhua/Then Chih Wey)

A smooth-coated otter grabs its 6-week-old pup in its mouth after swimming practise in a storm drain near Singapore River on Jan. 10, 2019. This family of smooth-coated otters, comprising of three adults and three otter pups, made their home in urban city centre of Singapore. (Xinhua/Then Chih Wey)

A 6-week-old smooth-coated otter pup learns to swim in a storm drain near Singapore River on Jan. 10, 2019. This family of smooth-coated otters, comprising of three adults and three otter pups, made their home in urban city centre of Singapore. (Xinhua/Then Chih Wey)

A 6-week-old smooth-coated otter pup learns to swim in a storm drain near Singapore River on Jan. 10, 2019. This family of smooth-coated otters, comprising of three adults and three otter pups, made their home in urban city centre of Singapore. (Xinhua/Then Chih Wey)

A family of smooth-coated otters make their way to a canal to practise swimming near Singapore River on Jan. 10, 2019. This family of smooth-coated otters, comprising of three adults and three otter pups, made their home in urban city centre of Singapore. (Xinhua/Then Chih Wey)

A family of smooth-coated otters make their way to a canal to practise swimming near Singapore River on Jan. 10, 2019. This family of smooth-coated otters, comprising of three adults and three otter pups, made their home in urban city centre of Singapore. (Xinhua/Then Chih Wey)