Which Mammals Live In Hawaii?


I went to Hawaii a few years ago, and I saw all sorts of animals whilst there.  From cage diving with tiger sharks to the beautiful butterflies in the evening, the islands were teeming with life.  If you are going to Hawaii, then read on, so you know what to expect from the beautiful Pacific islands.

There are 41 species of mammals in the Hawaiian Islands. The Hawaiian monk seal and hoary bat are native to Hawaii. There are four other species of carnivores, seven ungulates, one species of rabbit, four rodents, one wallaby, six species of dolphin, and sixteen different types of whales in Hawaii.

There are many islands in Hawaii.  If you would like to find out which animals you can see on each then the information here should help.

Hawaiian Hoary Bat

The hoary bat is one of two mammals native to the islands of Hawaii. They get their name from their appearance.  The coat is dark brown, with white tips and they are covered in fur apart from the underside of the wings. 

This bat is endemic to the island of Hawaii and is found on the islands of Hawaii and Kauai.  They may also be present in Kahoolawe Island.  They are very rare and are listed as endangered.    

Brush-tailed Rock Wallaby

The brush-tailed rock wallaby is the only marsupial in Hawaii, and one of only nine species of marsupial in North America.  The rock-wallaby can grow up to 58 cm in length, with its tail doubling this size.  They have grey-brown fur and can weigh up to 8 kgs.  

The only place to have a chance to see the only marsupial in Hawaii is in Oahu.  In 1916, a pair escaped leading to a small population of the brush-tailed rock-wallaby living today in Kalihi Valley.

Hawaiian monk seal

The Hawaiian monk seal is the only other mammal that is native to the Hawaiian Islands, and it is one of the two monk seals that are left in the world.  There are approximately 1,400 left and are a conservation reliant endangered species.

Males can weigh up to 400 pounds (180 kg) and 7 feet (2.1 m) in length, while females can weigh up to 600 pounds (270 kg) and 8 feet in length (2.4 km).  

The Hawaiian monk seal can be spotted basking on the beaches of the Leewards islands.  

Northern Elephant Seal

As a result of millions of years of evolutionary adaptation, the Northern Elephant Seal thrives in the Pacific Ocean.  Although not the largest mammal in the ocean, their name is derived from their size and their elephant trunk-like proboscis. 

Males are much larger and can weigh up to 2,300 kg (5,100 lb.) and can grow up to 16 feet.  Females are smaller growing up to 900 kg (1,90 lb.) and up to 5 meters (16 feet) in length. 

These are difficult to spot in Hawaii as they live at sea most of their time, only coming to land to give birth, breed, and molt.  

Indian Grey Mongoose

Although mainly found in West Asia and India, you can see the Indian grey mongoose in the Hawaiian Islands.  Covered in grey hair, the mongoose weighs up to 1.7 kg (2-4lb) with a tail that can equal their body length of 45 cm (17 inches).

It is against Hawaii State law for any person to introduce, keep, or breed any mongoose within the state except by permit due to their status as a pest. 

Seventy-two mongooses were introduced to Hawaii in 1883 by the sugar industry to keep the population of rats in the sugarcane down.  Mongoose is known as a pest as their negative impact outweighs their helpfulness as rat catchers.  You may be able to see the mongoose on all the islands except Lanai and Kauai.

Feral Cat

Domestic cats were introduced to many of the world’s islands, the Hawaiian Islands inclusive, where they mostly became the dominant apex predator in the absence of larger predatory animal species.

The consequences of their release have been particularly devastating for native wildlife. Several studies showed that island where the feral cats have been removed recover several endangered bird species as well as other wildlife. 

Feral Dog

The most popular dog in the Hawaiian history, although now extinct, is the Hawaiian Poi Dog. History has it that the Polynesian people brought the dog along with other domesticated animals and plants stocks when they immigrated into the Hawaiian land.

The dog was fed poi, a native food in the country, from where it got its name. A typical Poi Dog has short legs and a long body with a trademark flat head which is attributed to their diet. The poi dog couldn’t stand the test of time because of their sluggish nature.

Hawaiians only kept them to fuel their traditional beliefs and their bellies. The arrival of the Europeans settlers influenced the government and lifestyle of the Hawaiian people, and that included dumping the tradition of eating feral dogs.

The dogs that immigrated with the Europeans interbred with the poi dogs, and that was the beginning of their extinction.

So, if you find yourself in Hawaii today, it is not likely that you see a pure breed of the Hawaiian poi dog, even if you see one.

Chital

Also known as the axis deer, the chital is a moderately sized deer.  They are reddish-brown and covered in white spots.  Males have antlers, but females do not.  

The axis deer was introduced to Hawaii as a gift from Hong Kong.  These first deer went to the island of Molokai and then were added to Lanai.  They were also released on the big island, but this caused damage to landscapes. 

They have also been spotted on Maui following the introduction of four axis deer from Hawaii.  The axis deer can be found in Lanai, Maui, Molokai, and Oahu.

Domestic Goat, Feral Goat

Goats can be found all over Hawaii.  Due to the lack of large predators, the goat population has significantly expanded. You can see the domestic goat in Hawaii, Kahoolawe, Kauai, Maui, Molokai, Oahu.

Feral Cattle

The feral cattle you can see in Hawaii are not domesticated or cultivated.  They roamed the forested areas and were introduced at the end of the 18th century.  You can see feral cattle all over the island of Hawaii, but also in Kauai and Molokai.

Feral Pig, Wild Boar

The Wild Boar is not native to Hawaii. The wild pigs that you would find in Hawaii are products of crossbreeding of very bellicose Asian hog species and the huge European pigs.

Feral pigs feed on plants and animals. Only that they tend to eat more than an average human does, this characteristics feature makes them destructive and harmful to the environment. They eat anything in their way. 

The wild boars of Hawaii have caused a severe ecological disaster in the community. The wild hogs eat up the vegetation, uproot growing plants, and tamper with the healthy flora of the soil leaving the lands barren.

There are thousands of feral pigs all over the Hawaiian Islands; Hawaii, Kauai, Maui, Molokai, Niihau, and Oahu.

Mouflon, Feral Sheep

Mouflons are thought to be the progenitor of the domestic sheep breeds we have today. They were first introduced to the Hawaiian community in the late 1700s by the European settlers.

Before their invasion, as the Hawaiian people saw it back then, there were no grazing or browsing mammals in the state. 

Today, they are not commonly seen, but many of them live on the Islands in Hawaii and Lanai. The typical Mouflon sheep have short dark brown or reddish furs with a black streak on its back and white patches on the sides.

The ventral surface of the mammal and the legs are usually white. Some female mouflons have horns like the male ones, while the others do not. In mature rams, the horns are curved in almost one full revolution up to 0.85m in length.

Mule Deer, Black-tail Deer

The Black-tail deer is one of the two kinds of deer of which Hawaii boasts. You can find the other variant which is the axis deer all over Maui, Lanai, and Molokai while the black-tail deer is specific to Kauai. 

The bucks, whose coat color changes by seasons, tend to live the most of their lives in the same areas; they are not known to migrate like some other mammals. That could explain why they are not found on other islands of Hawaii; they settled at Kauai, and they remain there.

African Wild Ass, Feral Donkey

The single-toed African Wild Ass used to cause the Big Island community much havoc before they were taken in for adoption in 2016. The feral donkey is easy to spot in its short, smooth coat which could be as light as grey or dark as brown.

The donkey is usually about 2 meters long and about 1.45 tall at the shoulder level. Just like every other member of the Equidae family, the African wild ass has a long tail which can be about 20 inches long.

Feral European Rabbit

The European rabbit is native to southwestern Europe and northwest Africa. It has, however, been widely introduced elsewhere including Hawaii. When compared with the brown and mountain hare, the European rabbit is smaller and has proportionately shorter legs.

A mature European rabbit can be up to 40cm long, and 1.2 to 2kg heavy. Their sizes, however, vary according to the quality of habitat and food to which the rabbit is exposed. Some rabbits get to feed on rich roots and clovers while some depend on grasses only.

The introduction of these feral rabbits has caused devastating effects on the local biodiversity of Hawaii. The Feral European Rabbits eat out the vegetation leading to a consequent removal of soil insects on which many endemic birds are dependent.

The feral rabbit can be found on Lehua and Manana Island where eradicative measures have been taken.

Black Rat

Ship rats or house rats are known by many to be a nuisance, to farmers most notably, as they consume a wide range of farm produce. The state of Hawaii is not an exception.

Black rats are found on virtually all the major islands of Hawaii including Ford Island, Hawaii, Kahoolawe, Kauai, Lanai, Maui, Midway, Mokolii, Mokuauia, Mokuoloe, Molokai, Niihau, and Oahu.

The mammals which are also known as roof rats do not only come in black; their coat colors range from black to light brown with lighter underparts. 

Norway rat

The Norway Rat, like the black rat and house rat, can be found all over Hawaii. These little mammals have coarse furs which are usually brown or dark grey with their bellies assuming a lighter color of their coat.

The brown rat is a rather large rodent and can weigh twice as much as a black rat and many times more than a house mouse. The Norway rat is often found digging and burrowing under structures but is quite capable of climbing.

Polynesian Rat, Pacific Rat

Polynesian or Pacific rats are a major agricultural pest throughout Hawaii except at places like Mokolii, Mokuauia, and Mokuoloe. They eat a wide range of agricultural products, but most notably they cause terrible damage to sugarcane fields.

The Polynesian rats are smaller in size and have larger ears and longer snouts when compared to the Black rats and Norway rats.

These rats, including the two species I mentioned earlier, are not protected by any Hawaiian law. You may control them by any means, as long as your methods are consistent with the state’s rules and regulations.

House Mouse

The house mouse, Mus musculus, is one of the few domesticated mammals benefiting from their social interaction with man. The mouse is mostly seen in homes and also in the wild. It is known to carry over 40 deadly diseases, which is a significant threat to human health. 

A house mouse characteristically has a pointed snout, rounded ears, and a long tail. Their hair which covers virtually every part of their body, including the tail, can be of various colors ranging from black to brown to pristine white.

The house mouse is omnivorous and relies basically on the food that remains from humans to survive. They can be seen all over Hawaii; Ford Island, Hawaii, Kahoolawe, Kauai, Kaula, Lanai, Manana Island, Maui, Midway, Mokuoloe, Molokai, Niihau, and Oahu.

Bottlenose Dolphin

Bottlenose dolphins are the most common members of the oceanic dolphin family. These mammals which happen to be very useful to the human race; if they don’t get eaten, then they are performing at aquariums, zoos, or amusement parks.

The dolphin is considered the most intelligent animal of the aquatic environment, a feature which allows them to be trained and used for displays. Man, however, remains their primary predator. 

The bottlenose is mostly seen in shallow waters, less than 500 m deep, around the main Hawaiian Islands. It has been spotted severally in Hawaii, Maui, Lanai, Oahu, Kauai, and Niihau.

Risso’s Dolphin

If you would like more details on the bottlenose dolphin, I have put together 101 facts which you can find here.

The Risso’s dolphin is usually found in the deep waters of Hawaii where they feed nearly exclusively on neritic and squid. The easiest way to identify a Risso’s dolphin is its relatively large anterior body and dorsal fin which tapers posteriorly to its narrow tail.

Another distinct feature is its bulbous head which has a vertical crease on it. An adult Risso’s dolphin is a lot lighter in color, mostly white, than a young one whose skin could be grey or brown.

A study conducted on the Risso’s dolphins in Hawaii showed that they don’t flee from boats as a striped dolphin would. It is, however, difficult to get close to these mammals.

Their social interaction may explain the massive scars seen on their body. Risso’s dolphin is unusually covered with scars even more than the toothed whales whose injuries are a common phenomenon.

Pan tropical Spotted Dolphin

Thanks to the inception of the “dolphin-friendly” tuna capture methods, there are still millions of pan tropical spotted dolphins across the globe.

The species which seemed to be on the verge of extinction in the mid-18th century is now one of the most abundant dolphin species in the world. In Hawaii, pan tropical spotted dolphins are found in shallow waters (<100 m) and also in the deep offshore waters (>4000 m). 

The pan tropical spotted dolphins rely on the epipelagic zone for their food, but may sometime feed on squids and crustaceans. 

Rough-toothed Dolphin

Typically, the rough-toothed dolphins are found in deeper parts of Hawaii, most notably in Oahu, Kauai, and Niihau. Usually, these dolphins move in groups where a group can have up to 100 individuals.

These mammals are quite easy to differentiate from the other members of the dolphin family. They have a characteristic conical head and a long and slender nose where other dolphins have more bulging forehead and shorter muzzle.

An average rough-toothed dolphin is taller than an average human; their height ranges from 2.09m to 2.83m.

Spinner Dolphin

The spinner dolphin is famous for its beautiful acrobatic displays in which it spins along a longitudinal axis as it jumps into the air. In Hawaiian waters, spinner dolphins top the list of the most populous delphinid species.

The small-sized dolphins (129–235 cm long) are usually found along the leeward coasts of all the major islands in the state. Some studies have also reported to see them around several of the atolls of the main island chain. 

These dolphins get their food from the nutrient-rich mesopelagic community. These are known to seek out shallow coves daily to rest and hide from predation.

Striped Dolphin

The major recognizable factor of the striped dolphins is their stripes. A dark grey or blue stripe runs from the whale’s beak, over the eye and downwards across its side to the underpart of the body.

Another more colored line extends from under the eye to the pectoral flipper. These relatively small mammals have a colorful and streamlined body which adds to their beauty.

They live in the waters off Hawaii and other parts of the United States such as the west coast, the northwestern Atlantic, and in the Gulf of Mexico. These mammals, however, are not found in the boreal waters and colder region of Alaska.

Blue Whale

The Blue Whale is one of the most rarely seen large whales off Hawaii. However, history has it that the whales have been sighted severally during winter.

A typical blue whale has a long and slender body that can be of shades of bluish-grey dorsally which becomes lighter ventrally. There are lots of myths and legends about the blue whale, some of which are true.

The whale remains the largest animal on the earth’s surface with a body length of about 29.9 m and a maximum recorded weight of 173 tons. 

If you would like more details on the blue whale, I have written an article with 101 facts, which you can find here.

Blainville’s Beaked Whale

Blainville’s beaked whales are found in both tropical and temperate water. These huge mammals have been spotted severally off Oahu and the coast of Hawaii. The whales are known to be deep divers reaching as far as a depth of 1,000 fathoms.

This behavior makes it quite challenging to study the morphological features of a live beaked whale. For many decades, the skeletal remains of Blainville’s beaked whales are a significant way to identify them as living species.

The most striking diagnostic features of M. densirostris are the density and shape of the mandible as well as the position of the two mandibular teeth. The female dense-beaked whale, however, doesn’t have erupting teeth. The bulges on the jaw are present regardless.

Cuvier’s Beaked Whale

The Cuvier’s Beaked whale has a nose which resembles that of a bottlenose’s dolphin. Its other characteristic features include a forehead that gently slopes to a slight beak and two teeth that is only obvious in a closed mouth.

The beaked whales are famous for diving the deepest out of marine mammals.

Based on a study, the Cuvier’s beaked whales are the seventh-most frequently seen of the toothed whale species in Hawaii even though they prefer preferring deep pelagic waters (>1000m).

Common Minke Whale

The common minke whale is one of the two species of the minke whales which are generally considered the second smallest baleen whales.

Reports say the maximum length of a male and female common minke whale varies from 8.8 to 9.8m and 9.1 to 10.7m respectively. Both sexes typically weigh between 4–5 tons, but a maximum weight of 10 tons is achievable.

The common minke whales are present in the Northwestern Hawaiian Islands, and their major distinguishing feature is a white band on each flipper.

The color of their body can be black or dark-gray dorsally and white underneath. There have been sightings of the common minke whales near Kauai and Oahu.

False Killer Whale

The False Killer Whale population on the Hawaiian Islands is said to be on the list of endangered sea mammals. There are two groups of Hawaiian False Killer Whales; there is the “insular” population, found nearer the islands and a broader community that lives in offshore waters.

The former has decimated over the decades and is said to have less than 150 individuals, while the latter which are genetically separated are rarely or never be seen by visitors.

Closer to the shore of the major Hawaiian Islands, these mammals are found to be very predatory and enjoy the yumminess of the yellowfin tuna. They are also inhabitants of the blue waters between Maui and Lanai.

Fin Whale

The Fin Whale is one of the largest earth mammals rivaled only by the blue whale. It is called the Fin back whale because of its prominent dorsal fin which lies in the posterior one-third of it back.

Fin whales belong to the parvorder of baleen whales. They feed by filtering small schooling fish, squids, and crustaceans from the waters. The fin whales were hunted mainly in the 21st with over 725,000 captures in the Southern Hemisphere alone.

A moratorium was placed on these mammals to reduce whaling activities and consequently conserve the species. 

Researchers have documented more sightings of fin whales than blue whales in Hawaiian waters, most notably around Lanai and Kona.

Short-finned Pilot Whale

Short-finned Pilot Whales are large exotic species of the Delphinidae family second in size only to the Killer whale. Their name “pilot whale” is attributed to a significant characteristic behavior of the whales in which a leader whale leads a pod or group.

The short-finned population in Hawai’i are entirely genetically different from the other groups in the Pacific waters. Plot whales move in groups of about 25 to 50 individuals where one mature male pilots eight or more adult females. 

Short-finned pilot whales can be easily identified with their low and falcate dorsal fins as their name implies. The dorsal fins vary in size and shape depending on the age and sex of the whales.

Another noticeable feature is a relatively large bulbous head which is more prominent in the adult male population.

Pygmy Killer Whale

The Pygmy killer whale is so-called because of its similar characteristics with the killer whale. The skin of these mammals is dark grey or black on the cape, which changes abruptly to light grey on the sides.

They can be easily confused with Melon Headed whales because of their round bulbous heads.

Pygmy killer whales are seen and observed several times a year within Hawaiian waters. The Hawaiian population of the Pygmy Killer Whale (unlike pygmy killer whales anywhere else in the world) seems to be “regular” inhabitants of the coastline.

These whales remain isolated in one area and don’t venture out to the open ocean. They are usually not found father than 10 miles away from the Hawaii shores.

Sperm Whale

Sperm whales are the largest toothed whales, and the Hawaiian Islands seem to have them in abundance. Back in the 19th century, the Hawaiian waters was a marked whaling ground for sperm whales.

These mammals aren’t big for nothing whales as they boast of the largest and most complex brain on the earth’s surface encased in a humongous head.

These animals, however, have very narrow lower jaws which house a set of teeth. The baleen whales don’t do much with their teeth as they are filter feeders. Their primary preys are giant squids and fishes.

Sperm whales prefer deeper depths, which is their primary feeding zone and can dive as deep as 3000ft. Recorded sounds confirm the presence of the sperm whales in Oahu over the years. There is about 7,082 Sperm whale abundance in Hawaii with the figures peaking during spring. 

Pygmy Sperm Whale

The Pygmy Sperm whales are one of the three existing sperm whales. They are rarely seen at sea and most of what of the documentation about them came from studying stranded specimens.

In Hawaii, the pygmy sperm whale is less encountered than the other extant sperm whales. It is quite safe to say these whales are smaller versions of the sperm whales. They, however, have their differences. From the cephalic region, the head is blunt and relatively smaller.

Pygmy sperm whales have their mouth on the underside of their body like the sperm whales, but their dentition is a lot different. They have fewer and smaller teeth whose edges are sharp and curvy. Talking about their method feeding, unlike the sperm whales, they are suction feeders.

Dwarf Sperm Whale

Dwarf sperm whales live mostly offshore; they have been spotted severally in the deep waters off of the Lanai and Kona coastlines.

They are deep-divers which explains why they are rarely seen above water except on rare occasions when they are logging or lying motionlessly on the water surface.

Besides their choice of the aquatic habitat which makes them difficult to find, this species has a characteristic small body size and a high tendency to dodge vessels. An adult dwarf sperm whale is up to 2.7 m long and may weigh about 272 kg, while at birth, their length is about 1m.

Eden’s Whale

The Eden’s whale is a smaller form of the Bryde’s whale, Balaenoptera brydei, and it is commonly found in the Northwestern Hawaiian Island and the Indo-Pacific.

Not much is known about Eden’s whale. They are often seen in groups of 10 to 20 individuals during food hunts. Majorly, they feed on fish, but they also eat invertebrates via active lunge feeding.

If you would like more details about whales, I have written an article on the ten largest whales in North America. You can find it here.

Bryan Harding

Bryan has spent his whole life around animals. While loving all animals, Bryan is especially fond of mammals and has studied and worked with them around the world. Not only does Bryan share his knowledge and experience with our readers, but he also serves as owner, editor, and publisher of North American Mammals.

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