40 Fun Facts About Irrawaddy Dolphin

Irrawaddy dolphins are famous for which unusual habit at the surface, which may help herd fish?

Spit streams of water is the Irrawaddy dolphin's party trick, with jets reaching up to 1.5 meters. The squirting may herd fish, or simply clear water swallowed during a catch.

The small Irrawaddy dolphin is widely described as a close relative of which much larger ocean giant?

Killer whale is the surprise: early genetic studies paired the two, though newer work places the slow, shy Irrawaddy dolphin nearer the pilot whales.

The Irrawaddy dolphin's bulging forehead and blunt face make it look most like which Arctic whale?

Beluga is the lookalike, thanks to the same rounded head and stubby snout. Scientists once even placed the two animals in the same family before genetics separated them.

How do cast-net fishers on the Ayeyarwady River traditionally call Irrawaddy dolphins to help them catch fish?

Tap a stick on the boat and willing dolphins answer, herding a shoal toward the net in a tightening half-circle. Their reward is the fish that slip out as the net comes up.

Many Cambodian villagers along the Mekong River traditionally believe that Irrawaddy dolphins are what?

Reincarnated ancestors is how many river communities see the dolphins. The belief has helped people and dolphins live side by side peacefully for generations.

The Irrawaddy dolphin is named after a great river that runs the length of which Southeast Asian country?

Myanmar is split from north to south by the Irrawaddy, now officially spelled Ayeyarwady. The dolphin kept the old spelling, though most of its kind live far from that river.

The Irrawaddy dolphin stands out from most other dolphins because it lacks which familiar feature?

A long beak is missing from the Irrawaddy dolphin, whose forehead bulges out over a blunt mouth instead. Its species name, brevirostris, is Latin for short-beaked.

Some villagers in Cambodia claim Irrawaddy dolphins have protected people from attacks by which river animals?

Crocodiles are the attackers in these tales, which also tell of dolphins rescuing villagers in trouble in the river. Such stories help explain why many river people refuse to harm them.

Many Irrawaddy dolphins live in the Sundarbans, a tiger-haunted delta that is the world's largest what?

Mangrove forest covers about 10,000 square kilometers of the Sundarbans, a tidal maze of channels. That blend of river water and seawater is just what Irrawaddy dolphins favor.

Irrawaddy dolphins make clicks, creaks and buzzes at about 60 kilohertz, sounds thought to be used for what?

Echolocation lets the dolphins find fish in muddy water where eyes are little use. They read the echoes of their own clicks, pitched far too high for people to hear.

Across the Irrawaddy dolphin's range, what is the main cause of death, blamed for most dolphins found dead?

Drowning in gillnets tops the list, because a dolphin snared in the mesh cannot surface to breathe. On one Indonesian river, nets are linked to about 70% of dolphin deaths.

A few Irrawaddy dolphins cling on in Songkhla Lake, the largest natural lake in which country?

Thailand's Songkhla Lake is really a lagoon complex, joined to the sea by a narrow strait. By 2022 surveys had found just 14 dolphins there, prompting talk of artificial breeding.

On parts of the Mekong River, Irrawaddy dolphins have been killed by fishers using what instead of nets?

Explosives thrown into the water kill fish wholesale, and dolphins swimming nearby die with them. The noise of the blasts is itself thought to be dangerous to the dolphins.

Which international organization set up the Cambodian Mekong Dolphin Conservation Project for Irrawaddy dolphins?

WWF set the project up in 2005 with the Cambodian government and local communities. River guards now patrol a protected stretch of the Mekong to keep the dolphins safe.

Observations of captive Irrawaddy dolphins suggest they often take food into the mouth using which method?

Suction pulls prey straight into the mouth, a handy trick for an animal with a short, blunt face. The menu covers fish, squid, octopus, cuttlefish and crustaceans.

Unlike most dolphins, the Irrawaddy dolphin has visible skin creases because which body part is so flexible?

Its neck bends freely, which leaves visible creases behind the head. When scouting, an Irrawaddy dolphin lifts its head out of the water and rotates to look around.

The death of a lone male in 2022 left the Irrawaddy dolphin extinct in which country along the Mekong River?

Laos lost its last known dolphin when a 25-year-old male from the pool on the Cambodian border was found dead. The tiny group there had been shrinking for years.

The river behind the Irrawaddy dolphin's name is thought to be named after the god Indra's mount, which animal?

Elephant: the river's name is thought to come from Airavati, the elephant ridden by Indra, since elephants were a common symbol for water. So the dolphin is, in a roundabout way, named after one.

Studies found that noisy high-speed vessels make Irrawaddy dolphins do what for significantly longer than usual?

Stay underwater is the dolphins' answer to engine noise, with dives lasting significantly longer when fast boats pass. They also changed direction whenever large vessels came near.

Biologists call the Irrawaddy dolphin a euryhaline species because it can tolerate a wide range of what?

Salt levels barely matter to this dolphin, which is at home on sea coasts, in estuaries and far up great rivers. Such adaptable animals are typical of places where the mix keeps changing.

An 1879 report said fishers who believed their own Irrawaddy dolphin had filled a rival's nets often did what?

Sued for a share is what plaintiffs did in native courts, claiming a cut of the fish their dolphin had helped drive into a rival's net. Villages each claimed particular dolphins as their own.

In one Indonesian folk tale, Irrawaddy dolphins began as hungry children who ate what in a shaman's hut?

Pot of rice, in a legend told along Indonesia's Mahakam River: lost children ate one cooking in a shaman's hut, grew unbearably hot, leapt into the river and became dolphins.

Which British anatomist, who coined the word Dinosauria, described the Irrawaddy dolphin for science?

Richard Owen described the species in 1866 from a specimen found years earlier in an Indian harbor. He was also the driving force behind London's Natural History Museum.

Which dolphin, named a separate species in 2005, is the Irrawaddy dolphin's only fellow member of genus Orcaella?

Australian snubfin dolphin groups were long assumed to be Irrawaddy dolphins, until skull, color and DNA differences split them off. It was the first new dolphin species named in 56 years.

The Irrawaddy dolphin's range runs from the Philippines and Indonesia west as far as which body of water?

Bay of Bengal coasts mark the western edge of a range that hugs shorelines and river mouths all the way. Reported sightings in Chinese waters have been judged unreliable.

Which treaty moved the Irrawaddy dolphin to its strictest list, Appendix I, banning all commercial trade?

CITES made the move in 2004, placing the dolphin among the species judged to be threatened with extinction. Appendix I is the highest level of protection the treaty offers.

Which lagoon in India's Odisha state is famous for Irrawaddy dolphins that tourists watch from Satapada village?

Chilika Lake counts the Irrawaddy dolphin as its flagship species, with well over 100 in residence. Numbers rose after a new mouth to the sea was opened in 2000, bringing back fish, prawns and crabs.

The Mahakam River, home to a few dozen endangered Irrawaddy dolphins, flows across which large island?

Borneo's Mahakam shelters only about 70 of the dolphins, known locally as pesut. Heavy fishing and boat traffic make the river a dangerous home.

In 2009 researchers announced a find of nearly 6,000 Irrawaddy dolphins in the waters of which country?

Bangladesh turned out to hold far more Irrawaddy dolphins than anywhere else: before that count, the largest known populations numbered in the low hundreds or fewer.

Irrawaddy dolphins often rise upright to poke their heads out and look around, a behavior called what?

Spyhopping lets a dolphin check its surroundings above the waterline, slowly and under control. Captive Irrawaddy dolphins have even been trained to do it on command.

The Irrawaddy dolphin's bulging forehead holds a mass of fatty tissue, found in all toothed whales, called what?

Melon is the name for the rounded lump, which is thought to focus the sounds a toothed whale sends out. The Irrawaddy dolphin's is large, giving its head a globe-like shape.

Irrawaddy dolphins became popular in dolphin shows partly because, unlike most dolphins, they can be kept in what?

Freshwater tanks spare a venue the high cost of running a seawater system, which made the species a tempting catch. By 2002 Asia had more than 80 dolphinariums.

Decades ago, hunters along the Mekong River killed Irrawaddy dolphins chiefly for what?

Their oil was the prize: in the 1970s many Irrawaddy dolphins along the Mekong were slaughtered for it. Intensive net fishing soon took over as the bigger threat.

Malampaya Sound, where a colony of Irrawaddy dolphins was discovered in 1986, lies on which Philippine island?

Palawan's Malampaya Sound has a shallow, brackish inner basin that suits the dolphins. Their numbers there fell from 77 to about 35 in under three decades.

Which Cambodian town on the Mekong River counts its nearby Irrawaddy dolphins as its main tourist attraction?

Kratie lies just south of a stretch of river that is home to the rare dolphins, and boat trips to watch them are the town's big draw.

An Irrawaddy dolphin surfaces with a gentle roll and lifts which body part clear only before going deep?

Its tail fluke stays hidden during ordinary breaths and rises clear of the water only at the start of a long descent. A typical one lasts around two minutes.

Conservationists warn that building what on the Mekong River could doom its remaining Irrawaddy dolphins?

Hydropower dams are the fear, because the dolphins are so few and their range so narrow that a single project could critically endanger a whole population.

Irrawaddy dolphins have no distinctive markings, just a paler belly beneath a back of which color?

Slate gray to slate blue covers the back and sides, while the shape of the small dorsal fin differs from one dolphin to the next.

The Irrawaddy dolphin's U-shaped blowhole is described as unusual among dolphins because it opens in which direction?

Toward the front is the odd answer, and the blowhole also sits to the left of the body's midline. The forward-facing opening is one of the quirks that sets the species apart.

The specimen behind the first description of the Irrawaddy dolphin was found in the harbor of which Indian city?

Visakhapatnam, a port on India's east coast, yielded the animal in 1852, fourteen years before the species was described. The dolphin's story began far from the river it is named after.