Singapore is home to a plethora of mammals, with the more well known ones being terrestrial mammals like macaques and wild boars. However, did you know that Singapore also harbours a small but substantial number of largely-aquatic mammals?
These mammals that rely largely on water bodies for their lifestyle can be split into two categories – freshwater and marine mammals. Let us dive right into introducing some of these native animals!
Freshwater
You might have seen the news about otter sightings in Singapore – especially those about the Bishan Family! In the 1970s, these adorable critters used to thrive in Singapore but saw their numbers slowly dwindle due to the loss of their habitats due to water pollution and the reclamation of peat swamps and mangroves1.
Fortunately, their populations have risen over the years and are even celebrities of our local parks2! Otters are generally found in mangroves, rivers, and the coast and have a diet comprising fish, crustaceans, and molluscs (although sometimes they can be found touring Singapore).
Singapore is home to two species of otters – the smooth-coated otter (Lutrogale perspicillata), and the Asian small-clawed otter (Aonyx cinerea). The smooth-coated otter is the more commonly-seen species on mainland Singapore, with its ‘Critically Endangered’ dropped in 2021. (It is still endangered though!) They are found in areas such as Pasir Ris Park, Sungei Buloh Wetlands Reserves, Bishan Park, Marina Reservoir, and Punggol Waterway. These critters can be identified by their large size, webbed feet and prominent claws.
However, with every celebrity comes controversy: this species of otters occasionally makes the news for its luxurious appetite. Back in 2015, they were found eating more $80,000 worth of koi from a resort and home in Sentosa3!
On the other hand, their smaller-sized cousins, the Asian small-clawed otter, are found generally on the offshore islands of Pulau Ubin and Pulau Tekong. These elusive creatures possess incompletely webbed feet and smaller claws, hence their name!
Marine
Out on the coasts of mainland Singapore are where a few of our marine friends roam! One such creature is the dugong (Dugong dugon). Commonly found in the Johor Straits, the dugong is a close relative of the manatee.
It uses its fluked tail to propel itself and utilises its thick flippers to steer underwater. Due to seagrass being their primary diet, dugongs have been given the moniker ‘sea cows’ for their grazing habits!
Like all mammals, dugongs require air to breathe. Hence, they need to surface every three minutes to take in air. Interestingly, it is thought that the sighting of dugongs out at sea by sailors inspired mermaid legends of old4!
Other marine mammals that are native to Singapore include the finless porpoise (Neophocaena phocaenoides) and three different species of dolphins. These cetaceans have been spotted in the Johor Straits, Singapore Straits, and at the coasts of a few of the southern islands like St. John’s and Lazarus islands 5. They are opportunistic feeders and mainly feed on fish, crustaceans, and cephalopods.
Finless porpoises are close relatives of dolphins. While they may look similar, they can be differentiated by their lack of a dorsal fin (that’s the one on top!) and beak. They also have a small head and are light grey in colour. They are amazing divers and have been seen to be able to dive for more than four minutes at one go 6!
The dolphins that inhabit Singapore’s waters are the Irrawaddy dolphin (Orcaella brevirostris), Indo-Pacific humpback dolphin (Sousa chinensis), and the Indo-Pacific bottlenose dolphin (Tursiops aduncus).
Out of the three, the Irrawaddy dolphin is the most peculiar looking: it lacks a beak and looks like it has a big smile! Its head is also rounded like a melon and has a dorsal fin which is reduced in size. Its body is dark blue-grey and has a lighter grey underside.
On the other hand, the Indo-Pacific humpback dolphin possesses a distinctive hump on its back. Their juveniles are dark grey in colour. As they mature, their body colour turns into a unique rose-pink hue. Hence, they are sometimes called pink dolphins, which the Singaporean soft drink is named after!
Lastly, the Indo-Pacific bottlenose dolphin is the classic dolphin that one would picture when they think of dolphins. Bottlenose dolphins in general have been popularised by their appearance on the TV and on big screens 7. The Indo-Pacific bottlenose dolphin possesses a longer beak and a more distinctive dorsal fin than other bottlenose dolphins. It also has a dark grey upper side and a light grey underside.
A Pressing Issue
These aquatic mammals are a rare sight to behold and they may get even rarer due to constant anthropogenic extinction pressures. While Singapore’s smooth-coated otter population has been steadily rising, others in the region are facing a different fate. Southeast Asia’s otters have often been a target for poachers to be sold in the pet trade which has resulted in a decline in their populations7.
Marine mammals fare no better. Land reclamation and marine pollution have caused the food sources of the dugongs and dolphins to be depleted. Furthermore, fishing lines and boat propellers are ever-present death traps for them8 9.
Our aquatic counterparts are majestic and incite awe in many. Beyond that, they are also vital parts of our freshwater and marine ecosystems, acting as both predators and prey for larger animals. Hopefully, this article has given you some newfound respect and appreciation for these beautiful and intelligent aquatic beings!
Glossary:
Crustacean – any chiefly aquatic arthropod of the class Crustacea, typically having the body covered with a hard shell or crust, including the lobsters, shrimps, crabs, barnacles, and woodlice.
Cephalopod – any marine mollusc of the class Cephalopoda, characterized by well-developed head and eyes and a ring of sucker-bearing tentacles. The group also includes the octopuses, squids, cuttlefish, and pearly nautilus.
Cetacean – (order: Cetacea) any member of an entirely aquatic group of mammals commonly known as whales, dolphins, and porpoises
Mollusc – any of a large phylum (Mollusca) of invertebrate animals (such as snails, clams, or squids) with a soft unsegmented body usually enclosed in a calcareous shell
Opportunistic feeder – an animal which feeds on a wide variety of prey and is able to adapt to whatever food becomes available
Additional Materials: Here is an amazing flowchart for identifying the four species of marine mammals introduced in this post.