Hawaiian Monk Seal
Spanning 1,200 nautical miles across the world’s largest ocean, the Pacific – are the rarely visited Northwestern Hawaiian Islands. Located hundreds of miles from the main Hawaiian Islands of Kauai and Nihau, this Hawaiian Archipelogo is comprised of dozens of volcanic remnant islands, atolls and shoals. It may be the last large-scale, predator-dominated and least disturbed coral reef ecosystem on the planet.
Here among these small and isolated land masses is where the Hawaiian Monk Seal lives. Only found in the Hawaiian Archipelgo – Hawaiian monk seals are among the most endangered marine mammals in the world and the rarest pinniped in US waters.
The Hawaiian monk seal is the state mammal of Hawai’i and one of only two mammals endemic to the “Aloha State” (the other being the endangered Hawaiian hoary bat).
With a traditional Hawaiian name meaning “dog who runs in rough water.” Hawaiian monk seals weigh around 375-450 lbs and measure up to 7.5 feet. Females are typically larger than males. They are silvery-gray in color with a lighter, cream colored underside and have large black eyes.
Hawaiian monk seals spend two-thirds of their time out at sea. They prey upon creatures that live along the sea floor including a variety of fish, crustaceans and cephalopods. They seem to prefer creatures that hide under rocks or the sand.
While they typically hunt close to the shoreline, they have been known to dive more than 1,500 feet below the surface and can hold their breath for up to 20 minutes.
When they do come ashore it’s usually to rest or give birth. Once a year, they molt, or shed their upper layer of skin and fur, on sand, corals or volcanic shorelines.
Hawaiian monk seals are mostly solitary, coming together during breeding season. The main breeding populations are found at the northern-most coral atoll in the world – the Kure Atoll, as well as the Midway Islands, Pearl and Hermes Reef, and the French Frigate Shoals, a location also used as a nesting site by the Hawaiian Green Sea Turtles.
Mating occurs underwater. Gestation lasts up to 11 months and females give birth to a single pup. Pups are born with a fine coat of black hair known as “lanugo”, which they will molt around the time they are weaned.
They nurse for about 39 days, during this time the mother stays ashore and goes without eating. Some females monk seals have even been known to foster other pups.
When the pup is weaned, the mother will return to the sea and the young seal will be left to learn how to hunt on its own. Typically theycan live 25-30 years, although few make it that long…
The Hawaiian monk seals is one of three monk seals species, along with the Mediterranean and Caribbean monk seal. Sadly, the Caribbean monk seal was believed to have gone extinct in the 1970’s. It is estimated there may be fewer than 1,000 Hawaiian monk seals remaining.
While the Hawaiian monk seal’s main natural predator is the tiger shark, these seals face many more dangers. Pup mortality, predation, disease, aggressive male seals, habitat loss, interactions with human activities and entanglement are all threats to their survival.
Hawaiian monk seals, especially young ones, become entangled more than any other pinniped species.
Although commercial fishing fleets are prohibited from operating in Hawaiian monk seal habitat, the ocean is still haunted by discarded fishing gear. “Ghost nets” drift in from faraway places, trapping marine life like fish, turtles and seals as they go.
While humans may be the monk seals greatest threat, we can also be their greatest hope.
In September of 2014, the Marine Mammal Center (based in California) opened a new hospital for Hawaiian monk seals in Kailua-Kona on the Big Island. The facility is called Ke Kai Ola, meaning “the healing sea.”
Currently, the Minnesota Zoo is the only place outside of Hawai’i where you can say “aloha” to Hawaiian monk seals in person. The seals were rescued and deemed non-releasable then given a new home at the zoo where they help educate the public about the plight of these endangered Hawaiian natives in the wild.
Nene (Hawaiian Goose)
Located in the middle of the Pacific Ocean, lies the island state of Hawai’i. Comprised of eight main islands and dozens of atolls and shoals – these remote volcanic land masses are home to some of the world’s rarest and unique animal species.
Due to the isolated habitats and human encroachment, many of the endemic animals are now endangered. More than 25% of the endangered species found in the United States are native to the Hawaiian Archipelago.
Birds make up the largest portion of these protected animals and one species is designated as the Hawaiian State bird – the Nene – or Hawaiian Goose.
The local name, Nene, is derived from the sounds they make. Nene were once widely distributed among the main Hawaiian islands; although they are capable of flight, their wings are reduced in size, and they do not migrate or even travel between islands.
Hawaiian geese have a black face and crown and cream-colored cheeks. The neck is pale grayish streaked with black and has a narrow dark ring at the base. The body plumage and folded wings are gray-brown. The bill, legs and feet are black. Both sexes are similar in appearance, but males typically are larger.
Unlike all other geese, the Nene’s feet are not completely webbed. The longer toes and extra padding helps them move around on the rugged, rocky terrain of Hawaii’s lava fields where they are often found.
Though classified as waterfowl, the Hawaiian Goose is not dependent n freshwater or open bodies of water and they rarely swim. They are herbivores – browsing and grazing on leaves and seeds of grasses and sedges, flowers, and various fruits. They get most of their hydration from the fruits and berries they consume but they will drink water when available.
The breeding season of wild Nene in Hawaii generally begins in October and ends in February. This tends to corresponds more or less with the wet winter season in Hawaii, when most plant growth occurs.
Mates are together for life. Nests are built on the ground using variety of habitat types and elevations often on the sides of volcanoes. Nests are bowl-shaped lined with vegetation and down, usually hidden under shrubs. Females lay 2-5 eggs per nest.
Goslings are raised by both parents. Fledging occurs at 10-12 weeks after hatching. Adults molt following the breeding season when they are flightless for 4-6 weeks, generally gaining flight feathers at same time as their offspring.
The Hawaiian goose is among the most isolated, sedentary and threatened of all waterfowl. It is the sixth most endangered waterfowl species worldwide. Hunting, egg collecting and predation by introduced mongooses, cats, pigs, dogs and rats contributed to the historic decline of this species.
The Nene is the only surviving goose of the nine that were originally native to the islands. The other eight and a total of 32 bird species have gone extinct since the late 1700s.
Today, the nene is the world’s rarest goose. Its total population was estimated at around 25,000 birds before Captain James Cook “discovered” Hawaii in the 1770s. But by the 1950s only about 30 were left, all of which were on the “Big Island” of Hawaii.
The Hawaiian goose was declared endangered in 1967, captive breeding programs in both Hawaii and England allowed the release of over 2000 birds back into their native habitat. However, due to the earlier introduction of domestic animals plus an invasive mongoose population this first reintroduction program was not very successful. Fortunately due to perseverance, education and ongoing conservation efforts, the reintroduction of the Nene across 5 of the main Hawiian Islands, including Oahu, has finally taken hold and the Hawaiian Goose native population is on the rise. The Nene remain protected today.
One of the most widely recognized and beloved fish found on the Hawaiian reef is the small, angular triggerfish known traditionally as the humuhumunukunukuapua’a (who-moo-who-moo-noo-koo-noo-koo-ah-pooah-ah). Often referred to as humuhumu or simply humu for short.
Also known as the Hawaiian or reef triggerfish, they reach lengths up to 10 inches and are recognizable by their blue markings over their pointed, narrow mouth, a black band on their side and two distinct yellow triangle markings toward their tail fin. – The are one of nearly 40 triggerfish species found in the world’s oceans. The local name humuhumu is often used as a general name for both the reef triggerfish and the less common relative, the lagoon or Picasso triggerfish.
Like all triggerfish, humus can move each eye independently, which may help them keep a watch on approaching predators. They can also control the pigment of their scales to adjust their colors from a plain, drab look when threatened (which may help them blend into the sandy bottom) to bright and vibrant colors for which they are known.
When threatened, the humu may dive into a crevice in the reef, then wedge itself in by erecting the large dorsal spine on its head. The spine is locked into place by a second, smaller spine behind it that can only be unlocked by the fish itself. Another spine on the fish’s belly also extends to help wedge the fish securely into its shelter.
Triggerfish also use this wedging behavior at night while resting, often using the same spot each evening. Humuhumus may also be seen resting on their side.
The Humuhumu’s other defense mechanism is to make grunting noises that sound like a pig when fleeing from predators, which is believed to possibly be a warning call for other nearby humus as well.
The unique shape of the snout and the closeness of the fish’s teeth make the grunting sound possible. The mouth is very wide and the space inside is full of air, allowing it to produce the sound.
In addition, the air is used to blow jets of water from its mouth. These jets uncover organisms in the sand that may be eaten. Triggerfish are often seen spitting sand out of their mouths with the intention of sifting through the material in search these edible organisms. Humus feeds on algae and reef invertebrates, including snails, worms, brittlestars, sea urchins, and small crustaceans.
This behavior of rooting through the sand or rocks for food and making grunting noises when alarmed represented pig-like habits to early Hawaiians and is what gave the fish its local name: humuhumunukunukuapua’a. Roughly translated it means “the fish with the pig like snout” or “fish that snorts like a pig.”
Humuhumus are very territorial and are usually found alone rather than in schools like many reef fish species. In fact they can be quite aggressive toward their own species and even other fish of similar size. Humus have even been known to nip at swimmers who get too close.
The humuhumu is not highly valued as food, although it is edible and was recognized as such by early Hawaiians. The humus were also dried and used a cooking fuel. More importantly, both triggerfish species know as humuhumunukunukuāpua‘a were used as substitutes for pigs in some religious ceremonies.
The humuhumu is the official state fish of Hawai’i – a title given permanently in 2006. Despite this designation, humuhumus are not endangered like the state mammal – the Hawaiian Monk Seal or the Nene Goose, the state bird. In fact the humu is not found exclusively in Hawaiian waters but is also distributed across much of the south Pacific as well as the Indian Ocean to the coast of Africa and even into the Red Sea.
However, for the people of Hawai’i, the adored humuhumu has been featured in both art and music as it seems to capture the spirit of Hawaii—fiercely independent, stunningly beautiful, and unique.
Special thanks to the following organizations for their education, research and conservation programs that provided information for this episode:
Cornell Lab of Ornithology
Haleakalā National Park
Marine Mammal Center
Papahanaumokuakea Marine National Monument
University of Hawai’i / Waikiki Aquarium
University of Michigan’s Animal Diversity Web
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