Whales and dolphins are oceanic wonders, playing a crucial role in marine ecosystems. The nutrients they deposit and circulate help sustain and grow marine life, highlighting their importance in maintaining the ocean's delicate balance.
Sadly, many species face threats everyday due to habitat loss, pollution, and human activities making their populations dwindle, say the experts at Whale and Dolphin Conservation. Numbers for some are now so low that they face extinction. Others are so rarely seen that estimating how many are left alive is difficult.
- Why do whales breach? 6 theories behind their spectacular aerial shows
- Rarest sharks in the world: Before long many of these fascinating creatures could be extinct
In this article, we showcase 10 of the rarest marine mammals, exploring their distinctive characteristics, habitats, and conservation challenges. Due to their scarcity, some of these elusive creatures have rarely been photographed in the wild. Needless to say we have struggled to find images of some.
Rarest whales and dolphins in the world
1. Vaquita
Often referred to as the ‘panda of the sea’ due to the dark rings around their eyes, the little vaquita also has what appear to be black, ‘smiling’ shaped lips.
Unfortunately, the vaquita (Spanish for ‘small cow) doesn’t have much to smile about. In the late 90s there were around 600 individuals but now fewer than 10 remain rendering the species critically endangered, and very close to extinction.
90% of the population was lost between 2011-2016. Found exclusively in the northern part of the Gulf of California, Mexico, vaquitas are victims of accidental catch in illegal fisheries targeting yet another endangered species, a fish known as the totoaba. Smuggled into China, dried totoaba swim bladders, worth more than $10,000 each, are used to make maw, a soup thought to boost fertility.
2. Yangtze River Dolphin (Baiji)
Believed to be functionally extinct, the Yangtze River dolphin was native to China's Yangtze River. Industrial development, habitat degradation, and boat traffic led to its dramatic decline.
Though there have been unconfirmed sightings in recent years, no concrete evidence suggests a viable population remains.
3. Maui’s Dolphin
A subspecies of Hector’s dolphin, Maui’s are the world’s smallest and rarest dolphin and live close to the shore in shallower waters. Found only off the west coast of New Zealand’s North Island, their population is estimated to be fewer than 50 individuals.
They are curious by nature and sometimes quite boisterous, acrobatic, excitable and noisy. Accidental deaths in fishing nets are pushing these dolphins to extinction.
4. North Atlantic Right Whale
Once hunted to near extinction for their oil and baleen, North Atlantic right whales now number fewer than 400. They were given their name because they were relatively easy to hunt - slow moving, often feeding and socialising at the surface, they float when killed.
A coastal species, their range off the eastern seaboard of North America, intersects with intense human activity from shipping and fishing, both of which pose severe risks of vessel strikes and entanglement in fishing gear. Changing climate is adding to the challenge of protecting these whales from harm, as their distribution is shifting with their prey.
5. Rice’s Whale
This sub population of the Byrde’s whale was discovered in 2021. Resident year round in the northern Gulf of Mexico, they have a streamlined body with three ridges in the top of their flat, pointed head.
With an estimated population of fewer than 100 individuals, Rice’s whales are close to being wiped out by threats from oil spills, ship collisions, noise pollution and entanglement in fishing gear.
6. Hector’s Dolphin
The Hector’s dolphin population, endemic to New Zealand is in trouble with only about 15,000 individuals remaining.
Known for their rounded dorsal fins and playful behaviour, they have been reduced to less than 25% of their numbers in the 1970s by incidental capture in fishing nets, which is pushing these tiny dolphins to the brink.
The rare Maui’s dolphin, (see above) is a subspecies of this small marine mammal.
7. Omura’s Whale (Dwarf fin whale)
When it comes to sightings, the Omura’s whale is right up there in the rarity stakes. Very few of these baleen whales have been spotted making estimates of their number tricky.
This long, thin and super-streamlined whale has a distinctive snake-like appearance and, unlike other baleen whales, does not appear to undertake long migrations from one area to another each year.
Scientists know little about the distribution of these whales and the only genetically confirmed population of living whales identified so far by researchers is found off the coast of northwestern Madagascar.
8. Pygmy Right Whale
The pygmy right whale is a mysterious and seldom-seen species found in the Southern Hemisphere. Despite their name, they are not closely related to other right whales.
What is known about their population or behaviour comes mainly from those that die and wash up on the shore. It is not clear how many of these whales roam the ocean but one of the biggest threats to their population is from accidental capture in fishing gear.
9. Spade-Toothed Whale
You know a whale is rare when nearly all the information known about them is from skeletal remains. As such, the spade-toothed beaked whale has the distinction of possibly being the least known of all the world's whales.
Only around six have been reported since the 1870’s and only one complete whale has everbeen fully examined after washing up off the coast of New Zealand in late 2024.
Their elusive nature and deep-ocean habitat in the South Pacific make them very challengingto study. It is hard to know how many exist if they have never been seen alive!
10. Irrawaddy Dolphin
One of the world's weirdest animals, Irrawaddy dolphins inhabit coastal and freshwater regions in South and Southeast Asia. They are grey to slate blue in colour, with a high rounded forehead and no beak, rather similar in appearance to young beluga whale but they are not closely related.
Just like belugas, Irrawaddy dolphins have unusually expressive faces and can squirt water from their mouths into the air. They seem to perform this unusual behaviour when socialising and fishing. But they are in danger of disappearing altogether.
Certain subpopulations, such as those in the Mekong River and Ayeyarwady River, are critically endangered, with fewer than 100 individuals left. Threats include habitat degradation, pollution, and fishing net entanglement.
Why are these whales and dolphins rare?
The rarity of these whales and dolphins highlights the fragile state of marine ecosystems and species. Conservation efforts, including the creation of marine protected areas, transitioning to less damaging fishing practices, and international cooperation, are vital if they are tosurvive.
Raising awareness of their plight and urgently reducing human impacts can help ensure these magnificent marine mammals remain part of our planet’s biodiversity for generations to come.
