2-panel image showing two views of the fossil shell of an unidentified snail from the Pleistocene of Oahu. The shell coils in a spiral with spiral lines. The left view shows the spire of the shell, the right view shows the aperture (opening).

Fossils of Hawaiʻi

Page snapshot: Introduction to the fossils of Hawai'i.

Topics covered on this page: Types of Hawaiian fossils; How did organisms colonize Hawai'i?; Hawai'i before humans arrived; Arrival of humans and aftermath; Resources.

Credits: Most of the text of this page comes from "Fossils of the Western US" by Brendan M. Anderson, Alexandra Moore, Gary Lewis, and Warren D. Allmon, chapter 3 in The Teacher-Friendly Guide to the Geology of the Western US, edited by Mark D. Lucas, Robert M. Ross, and Andrielle N. Swaby (published in 2014 by the Paleontological Research Institution; currently out of print). The book was adapted for the web by Elizabeth J. Hermsen and Jonathan R. Hendricks in 2022. Changes include formatting and revisions to the text and images. Credits for individual images are given in figure captions.

Updates: Page last updated June 22, 2022.

Image above: Unidentified gastropod (snail) shell from the Pleistocene of Honolulu County, O'ahu, Hawai'i. Photo of YPM IP 533438 by Jessica Utrup, 2016 (Yale Peabody Museum of Natural History/YPM, CC0 1.0 Universal/Public Domain Dedication, accessed via GBIF.org).

Types of Hawaiian fossils

Most fossils occur in sedimentary rocks, but almost all of Hawai'i consists of igneous rock. Nevertheless, Hawai'i does have a fossil record, and most of these fossils are often found in three unusual geological settings:

  • Inside lava tubes or caves.
  • In limestones formed by the coral reefs surrounding the islands, which, when exposed to the air (when sea level falls or the island is uplifted) can become karst.
  • As charcoalified imprints of trees in or between lava flows.

Photograph of the inside of Nahuku, a lava tube on Hawaii. The lava tube looks like a tunnel with a flat floor. Lights mounted in the tube illuminate the scene and small tree roots hang from the ceiling.

Nāhuku (also called Thurston Lave Tube), a lava tube at Hawai'i Volcanoes National Park, Big Island (Hawai'i), Hawaiian Islands. Photo by J. Wei, NPS (National Park Service/NPS, public domain).


Many of the organic remains described from Hawai'i can be called subfossils. Subfossils are remains or traces of past life that are less than 10,000 years old, which is the standard (though arbitrary) age definition for fossils. In practice, such materials are treated like “true” fossils and provide the same kinds of information.

The fossil record of the Hawaiian Islands preserves a 400,000-year history of island biodiversity. Fossils of plants, birds, fish, terrestrial and marine invertebrates, and a lone native terrestrial mammal paint a picture of surprisingly diverse Hawaiian ecosystems prior to the arrival of the first humans.

Photograph of subfossil bones of the high-billed crow from Oahu. The bones are laying on a white surface, with two additional boxes containing white bones at the right of the image. Bones include skull and limb bones and a sternum. The boxes contain vertebrae and small bones, possibly ribs.

Bones of a high-billed crow (Corvus impluviatus), a bird that was endemic to the Hawaiian Islands but that went extinct after humans arrived. Specimen from the Cenozoic (near-recent) of O'ahu. Photo by Mark Florence (Smithsonian National Museum of Natural History, public domain).

Trace fossils

Trace fossils in Hawai'i are most often represented by the trunks and branches of trees that have been consumed by molten lava. When lava flows through a forested area, the molten liquid chills and solidifies almost instantly when it comes in contact with large vegetation. The lava is still quite hot—enough to ignite and burn the trees, leaving behind a mold of the former tree trunk. Lava flows commonly deflate and subside after solidification, and tree molds can protrude above the frozen surface of the flow, leaving behind “lava trees.”

Photograph of lava engulfing a tree on Hawaii. Red hot lava has surrounded the base of a tree, which has fallen over. The crown of the tree sits on cooled lava to the side of the new lava flow. The leaves of the tree are brown, and the trunk appears to be scorched.

Lava consuming a tree, Hawai'i Volcanoes National Park, Big Island of Hawai'i. Photo by Marius Arigot, NPS (National Park Service/NPS, public domain).

Photograph of a tree mold on Hawaii. The tree mold looks like a cylindrical pit in the ground. The roots of a living tree are growing down the side of the mold. Lichens also line the rocks of the walls of the mold, indicating that it is old.

Tree mold, Hawai'i Volcanoes National Park, Big Island of Hawai'i. Photo by National Park Service/NPS (public domain).

Marine fossils

Marine fossils in Hawai‘i are not widespread, but can be very abundant where they do occur, along the coasts of Kaua'i, O'ahu, Molokai, Lanai, and Maui. All are found in limestones formed by uplifted Pleistocene or Holocene coral reefs and can be studied either from coastal outcrops or from cores taken by ship. More than 150 species of mollusks (bivalves and gastropods) have been reported in these reef limestones, together with numerous fossil corals.

Photograph of two fossil Hawaiian top snail shells from Oahu. The shells are pinkish in color and have horizontal grooves. The apertures (openings) can be seen, although in one shell the aperture appears to be filled with sediment.

Fossil Hawaiian top shells (Turbo sandwicensis) from O'ahu, age not specified. Photo by David Eickhoff (flickr, Creative Commons Attribution 2.0 Generic license, image cropped).

How did organisms colonize Hawai'i?

As the most isolated archipelago in the world, the Hawaiian Islands were colonized by a relatively small number of species that could successfully disperse across the ocean by flying, floating, or being blown by wind. Most plants arrived as seeds carried by migratory birds, either carried in the birds' stomachs or stuck to their feathers or skin. A smaller number of organisms drifted on air or floated on plant matter in ocean currents.

Organisms that survived the voyage to Hawai'i and reproduced in their new environment were able to move into new ecological niches because there were few competitors for resources. The lack of competition gave rise to an adaptive radiation of species. An adaptive radiation is the creation of multiple new species from a colonizing ancestor. Long distance travel coupled with subsequent species radiation have given Hawai'i a very unusual and highly endemic group of organisms.

The long distance and duration of the trip to Hawai'i favored certain types of organisms and selected strongly against others. Thus, there are no native Hawaiian terrestrial reptiles and amphibians. There is only one terrestrial mammal, the 'ōpe'ape'a or Hawaiian hoary bat. In contrast, there are many native species of birds, terrestrial invertebrates, and plants. Even in the marine realm, the abundance of species is skewed toward those that could travel across the open ocean, and a similar adaptive radiation occurred following the arrival of early nearshore reef species. 

Photograph of a Hawaiian hoary bat. The bat is being held in a human hand and has its face toward the camera. Its mouth is slightly open, showing four pointed teeth in the front.
Photograph of a nene, or Hawaiian goose. The goose is shown in side view. It has a relatively short neck and long legs. Its face, the top of its head are black, and the back of its neck are black, whereas the rest of its head and neck and off-white. Its body is white and gray. 

A nēnē or Hawaiian goose (Branta sandvicensis), Kilauea Point National Wildlife Refuge, Kaua'i. Photo by Jörg Hempel (Wikimedia Commons, Creative Commons Attribution 3.0 Germany license, image cropped).

2-panel image showing view of both sides of eight land snail shells in the genus Endodonta from the Pleistocene of Oahu. The shells are very small (less than one half centimeter), coil in more or less a single plane, and are off-white in color with faint stripes on one side.

Shells of the land snail Endodonta, a genus of snails found only in Hawai'i. These specimens are from the Pleistocene of Honolulu County, O'ahu. Photo of YPM IP 533448 by Jessica Utrup, 2016 (Yale Peabody Museum of Natural History/YPM, CC0 1.0 Universal/Public Domain Dedication, accessed via GBIF.org).

Photograph of silversword plants growing in a barren landscape with mountains in the background. Each silversword has a cluster of silvery-green, lanceolate leaves at its base from which a stalk of large, nodding flowers emerges.

'Ahinahina or silverswords (Argyroxiphium) at Haleakala National Park, Maui. Scientists think that the silverswords descended from a California tarweed that reached the Hawaiian Islands over 5 million years ago. Photo by A. Rulison, NPS (National Park Service, public domain).

Hawai'i before humans arrived

Before the introduction of continental species by humans, Hawaiian terrestrial ecosystems lacked grazing mammals and were inhabited by large and often flightless grazing ducks and geese. The top predators were raptors (predatory birds). Plants lost certain defenses needed to guard against large grazing mammals. Carnivorous caterpillars (Eupithecia monticolens) evolved in Hawaiian forests. Nectar-sipping Hawaiian birds like the 'i'iwi (Vestiaria coccinea) coevolved with flowering plants and served as pollinators for some of them, like the endemic lobeliads and the 'ōhi'a lehua (Metrosideros polymorpha).

In addition to extinct species, many species of living plants and animals found in the fossil record no longer grow at low elevation; rather, they are found only in high-elevation refuges in remote parts of the islands.

Photograph showing an 'i'iwi, a red bird with black wings and a curved beak, in a 'ohi'a lehua tree, a type of tree with small leaves are clusters of red flowers.

An 'i'iwi, a type of Hawaiian honeycreeper, on a 'ōhi'a lehua tree in Hakalau Forest National Wildlife Refuge, Big Island of Hawai'i. Photo by USFWS-Pacific Region (flickr, Creative Commons Attribution-NonCommercial 2.0 Generic license, image resized).

Photograph of a koli'i tree on Oahu. The tree has pink flowers that occur in rows on horizontal branches that radiate from the central trunk of the plant. The leaves are elongated and strap-shaped.

Curved flowers of koli'i (Trematolobelia kaalae) a lobeliad that grows in the Wai'anae Mountains, O'ahu. These flowers are presumably adapted for pollination by birds with curved beaks, although this has not been established with certainty. Photo by David Eickhoff (flickr, Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Generic license, image cropped).

Ulupau Crater

The oldest terrestrial fossils in Hawai'i are found in lake sediments at the bottom of Ulupau crater on O'ahu. This fossil occurrence is an unusual one for Hawai'i and does not fall into one of the three more common modes of preservation described above. The island does not have many lakes, as its base is made up of porous lava. Eleven species of extinct birds have been identified there, dating to 400,000 years ago.

Makauwahi Cave

The richest fossil site in the islands is Makauwahi Cave on Kaua'i. Makauwahi is a karstic cave system in limestone containing a sinkhole lake in which sediments have accumulated over the last 10,000 years, providing excellent preservation. The hundreds of fossil organisms identified at Makauwahi include more than 40 species of birds (half of which are now extinct), 15 or more species of native land snails (all now extinct), and scores of endemic plants. One of the most curious species of bird is the Kaua'i mole duck (Talpanas lippa), which had unusually small eyes but very large nerve passages to its bill. Paleontologists believe that the mole duck was nearly blind; it may have inhabited caves or was perhaps a nocturnal feeder.

Photograph of Makauwahi Cave in Kauai. The photo shows a hill with an exposed limestone cliff face. At the base of the cliff is a roughly rectangular cave entrance. Three palm trees stand in front of the cave.
Photograph of an excavation pit at Makauwahi Cave, Kauai. The photo shows a rectangular, water-filled hole surrounded by earth walls that are stained green near the waterline. Aquatic plants float on the water in the pit.

Arrival of humans & aftermath

Arrival of Polynesians

Radiocarbon dating of specimens at Makauwahi Cave documents the arrival of humans and the continental species they introduced, as well as the relationship between these new arrivals and the native organisms. Human-caused extinctions began about 1000 years ago, after Polynesians settled in Hawai'i. Lowland birds, along with large flightless geese and ducks, were among the earliest extinctions. These species disappear from sedimentary layers shortly after the appearance of fossils of human-introduced Polynesian rats (Rattus exulans) and other evidence of human habitation. Early settlers also introduced dogs and pigs to the Hawaiian Islands. 

Photograph of a Polynesian rat take on Maui. The rat is a small rodent with medium-brown fur, black eyes, and pink paws.

A Polynesian rat (Rattus exulans) in Haleakala National Park, Maui, 2014. Photo byForest & Kim Starr (Wikimedia Commons, Creative Commons Attribution 3.0 United States license, image cropped and resized).

Photograph of a feral pig on Maui. The pig is covered in off-white hair with black spots.

A feral pig (Sus scrofa) in Keālia Pond National Wildlife Refuge, Maui, 2019. Pigs were first introduced to Hawai'i by Polynesian settlers, and today's feral pigs are thought to be descendants of these early pigs. Photo by Anita Gould (flickr, Creative Commons Attribution-NonCommercial 2.0 Generic license, image cropped and resized).

Photograph of the bones of an O'ahu moa nalo, a type of flightless duck. The bones are sitting on a blue cloth background. One bone appears to be the top park of the beak; it is gray in color and has a serrated edge. The other bone might be a sternum; it is off-white in color and relatively flat.

Subfossil bones of the O'ahu moa nalo (Thambetochen xanion), a flightless duck, Barbers Point sinkholes, O'ahu. This bird went extinct between the arrival of Polynesians and the later arrival of Europeans on the Hawaiian Islands. Photo by David Eickhoff (Wikimedia Commons, Creative Commons Attribution 2.0 Generic license, image cropped and resized).

Photographs of two claws of a land crab from the island of Maui. These claws date to before humans settled the Hawaiian Islands.

Claws of the land crab Geograpsus severnsi from Pu'u Naio Cave, Maui. Remains of Geograpsus severnsi have been found on Kaua'i and Maui, but the crabs vanished following human settlement of the islands. Scale bars = 1 centimeter (about 0.4 inches). Source: Images from Figure 1 in G. Paulay and J. Starmer (2011) PLoS ONE 6(5): e19916 (Creative Commons Attribution license, images cropped and reconfigured).

Late 1700s to today

Europeans first arrived in the Hawaiian Islands in the 1770s, and extinctions began accelerating soon thereafter. The extinction rate continues to increase even today. Factors include clearing of land for development and agriculture, the spread of diseases (for example, Avian malaria and Rapid 'Ōhi'a Death), and the impacts of introduced species like feral cats and pigs, mongooses, disease-carrying mosquitoes, and the aggressive tree miconia (Miconia calvescens).

Hawai'i’s highly diverse prehuman landscape is now completely transformed, with the decline or extirpation of most native species and their replacement with a small number of introduced species. For example, more than half of Kaua'i’s 140 historically described native bird species are now extinct. 

Photograph of a mongoose on O'ahu. The moongoose is brown with brown eyes and a brown nose. It has a long body, short legs, a long, bushy tail, and short, rounded ears. 

A mongoose (Herpestes javanicus) on O'ahu, 2016. Mongooses were imported to Hawai'i in 1883 and released to control rats in sugar cane plantations. Photo by Tony Hisgett (flickr, Creative Commons Attribution 2.0 Generic license, image cropped).

Photograph of land snail shells of the species Carelia cochlea from Kauai. The shells range from dark pink to orangish in color and are elongated in shape. Five shells are shown in the image, four in a line with their spires pointing upward, and one underneath with the tip of its spire pointed to the right.

Shells of Carelia cochlea, a land snail found only on Kaua'i. This species probably went extinct in the 1800s. Photo by David Eickhoff (flickr, Creative Commons Attribution 2.0 Generic license, image cropped).

2-Panel figure showing illustrations of extinct Hawaiian honeyeaters. Panel 1: Illustration of two Kaua'i 'ō'ō birds sitting on branches in a tree with orange flowers. The birds are black with brownish underbellies. Their beaks are nearly straight, showing only a slight downward curve. Panel 2: Illustration of a black mamo bird sitting on the branch of a tree with yellow flowers. The bird is mostly black, except for some yellow feathers on the edges of its wings. It has a black beak that curves strongly downward. 

Extinct Hawaiian honeyeaters. Left: Kaua'i 'ō'ō (Moho braccatus). This entire genus of birds (the 'ō'ō, genus Moho) is extinct, with different species disappearing between the 1830s and the 1980s. The Kaua'i 'ō'ō was the longest to survive, dying out around 1987. Right: Black mamo (Drepanis funerea). This species lived on Moloka'i and went extinct around 1907. Left and right paintings by John Gerrard Keulemans (via Wikimedia Commons, public domain).

Photograph of a Huelo Islet, a rocking islet jutting out of the water off the coast of Moloka'i. The top of the islet is covered with palm trees.

Loulu lelo or Moloka'i fan palm (Pritchardia hillebrandii) is one of about 19 species of loulu (Pritchardia, a group of palms) unique to the Hawaiian Islands. Feeding by goats, pigs, and rats has significantly reduced the wild populations of these palms. The palms above are growing on Huelo Islet (off Moloka'i), one of two islets with a remaining wild loulu lelo population. Photo by Forest Starr and Kim Starr (flickr, Creative Commons Attribution 2.0 Generic license, image cropped and resized).


Resources from the Paleontological Research Institution

Digital Atlas of Ancient Life Virtual Collection: https://www.digitalatlasofancientlife.org/vc/ (Virtual fossil collection featuring 3D models of fossil specimens sorted by group)

Digital Encyclopedia of Ancient Life: https://www.digitalatlasofancientlife.org/learn/

Earth@Home: Quick guide to common fossils: https://earthathome.org/quick-faqs/quick-guide-common-fossils/

Go to a list of resources about the fossils of the Hawai'i

Go to a list of general resources about fossils