Fact-checked by Grok 2 weeks ago

Polynesian rat

The Polynesian rat (Rattus exulans), also known as the Pacific rat or kiore, is a small in the family , native to and one of the earliest commensal mammals associated with human expansion across the Pacific. With a head-body length of 11–15 cm, a tail roughly equal in length, and an adult weight of 40–100 g, it has a slender build, coarse reddish-brown to gray-brown fur on the dorsum, lighter gray or white underparts, large ears, and relatively small feet adapted for climbing. Originally distributed across tropical mainland Southeast Asia, including regions like , , and , R. exulans was transported by Austronesian and Polynesian voyagers starting around 3,000–4,000 years ago, reaching remote islands such as those in , , and as a on canoes. This human-mediated dispersal made it the third most widespread globally, after the (Rattus norvegicus) and (Rattus rattus), though it has been largely displaced from some areas by these later introductions. Today, it thrives in diverse habitats including coastal grasslands, scrublands, forests, and agricultural areas, often closely tied to human settlements where it seeks shelter in burrows, tree hollows, or woven grass nests. Ecologically, the Polynesian rat is nocturnal and arboreal, with a confined to small home ranges of a few hundred square meters, though it exhibits opportunistic behaviors like using "husking stations" to process seeds. As an , its diet consists of primarily material—such as fruits, seeds, and roots—with significant animal matter, including like and , small , bird eggs and chicks, and occasionally carrion or human food scraps. occurs year-round in tropical environments, with females reaching at around 2–3 months in the wild (60–70 days in captivity), lasting 21–24 days, litter sizes of 3–8 young on average, and up to 4–6 litters per year depending on conditions, enabling rapid population growth under favorable conditions. Despite its adaptability, R. exulans is best known for its profound negative impacts as an on oceanic islands, where it preys on endemic , reptiles, and seabirds—contributing to the decline or of species like the Stephen Island wren in —and browses native vegetation, altering plant communities. It also serves as a significant agricultural , causing substantial damage to crops such as , , corn, and tropical fruits across and the Pacific. Additionally, its bones preserved in archaeological sites provide valuable genetic and morphological evidence tracing patterns, highlighting its role as a for prehistoric voyaging. A 2025 study suggests Polynesian rats were the primary driver of on Rapa Nui (). Management efforts, including trapping and poisoning, have successfully eradicated populations from numerous small islands, with recent successes as of 2024–2025 including Suwarrow Atoll in the and sites in the , aiding biodiversity restoration.

Taxonomy and nomenclature

Scientific classification

The Polynesian rat is classified in the domain Eukarya, kingdom Animalia, phylum Chordata, class Mammalia, order Rodentia, family Muridae, genus Rattus, and subgenus Rattus. Its binomial name is Rattus exulans (Peale, 1848), originally described as Mus exulans based on specimens from the Pacific region. Genetic studies using mitochondrial DNA (mtDNA) indicate that R. exulans originated in Southeast Asia, with the highest haplotype diversity found in island Southeast Asia, particularly on Flores in Indonesia, suggesting this as a key area of early diversification. Phylogenetic analyses estimate the divergence of R. exulans from other Rattus species at approximately 1.8 million years ago, placing it within the broader Asian clade of the genus alongside relatives such as R. norvegicus, R. rattus, and R. tanezumi. These mtDNA haplogroups, including unique lineages like H35 in ancient Flores samples, further support a Southeast Asian origin and subsequent dispersal via human activity. Cytogenetic analyses reveal a diploid chromosome number of 2n=42 for R. exulans, with a fundamental number (NF) of 58, consisting of metacentric, submetacentric, and acrocentric autosomes, consistent across populations from various localities. Up to 12 subspecies of R. exulans are recognized, formerly treated as separate species in the Concolor-Ephippium Group, reflecting regional morphological variations adapted to island environments. Notable examples include the nominotypical R. e. exulans, distributed across Pacific islands, and R. e. umbrinus, found in New Guinea.

Common names and etymology

The Polynesian rat (Rattus exulans) is commonly known as the Polynesian rat, Pacific rat, or little rat in English; kiore in ; and rat polynésien in . These names reflect its close association with settlements across the Pacific islands. Regional variations abound in indigenous languages, with numerous distinct names recorded in Polynesian tongues. For instance, it is called ʻiole in and imoa or rat des cocotiers in Tahitian, highlighting its integration into local cultures as a familiar commensal . The etymology of the binomial name underscores its migratory history. The genus Rattus derives from Latin for "rat," while the specific epithet exulans comes from the Latin exul, meaning "exile" or "wanderer," alluding to the species' extensive dispersal as a human companion far from its Southeast Asian origins. The vernacular "Polynesian" emphasizes its human-mediated spread by Polynesian voyagers across Oceania, distinguishing it from other rat species. Historically, the species was first formally described as Mus exulans by American naturalist Titian R. Peale in 1848, based on specimens collected from in the during the U.S. Exploring Expedition. Prior to scientific documentation, Polynesian oral traditions reference the rat as a voyage companion, carried aboard canoes during ancient seafaring migrations and valued in some narratives as a food source or cultural symbol.

Physical characteristics

Morphology

The Polynesian rat (Rattus exulans) exhibits a slender body build characteristic of many small rodents, featuring a pointed muzzle, large rounded ears, and relatively delicate limbs adapted for agility in varied terrains. Its fur is coarse, with spiny guard hairs, typically ranging from ruddy-brown to grey-brown on the surface, while the ventral pelage is lighter, appearing whitish or pale grey. The is a prominent feature, measuring approximately 100-130% of the head-body length, covered in fine, prominent scaly rings and sparsely haired, often appearing uniformly dark with subtle dorsal-ventral shading. Hind feet are five-toed with sharp claws, featuring a distinctive dark band along the outer edge near the ankle contrasting with the otherwise pale coloration, which aids in species identification. The follows the typical formula of 1/1, 0/0, 0/0, 3/3, with robust, continuously growing incisors that enable gnawing on diverse materials. Sexual dimorphism is minimal, with adult males generally slightly larger than females due to prolonged post-pubescent growth in linear dimensions and body mass; females possess eight mammary glands, fewer than the ten in the ship rat (R. rattus) or twelve in the Norway rat (R. norvegicus). Compared to these congeners, R. exulans is notably smaller overall, with a more gracile and proportionally shorter relative to body size, lacking the denser tail pelage sometimes observed in ship rats.

Size and variation

The Polynesian rat () displays notable intraspecific variation in body size, influenced by environmental and genetic factors across its range. Adult individuals typically measure 110–180 mm in head-body length, with tail lengths of 110–210 mm, often equaling or slightly exceeding the head-body measurement, and weights ranging from 35 to 180 g, though averages fall between 40 and 80 g in most populations. Sexual dimorphism is minimal, with males slightly larger than females on average, but age-related differences are more pronounced; juveniles generally weigh under 50 g at , while is attained at approximately 60–80 g in body weight, corresponding to about 2–3 months of age. size also varies with latitude, with individuals from cooler climates exhibiting larger skulls. In isolated island populations, insular is evident, following the island rule where reduced predation and limited dispersal lead to larger body and sizes; for instance, specimens from remote Pacific atolls can be more than twice as large as forms (relative body size indices reaching 2.07 times the Southeast Asian baseline). On Henderson , rats exhibit near-double dimensions (relative size index of 1.92), reflecting to seabird-rich environments. Size variation is primarily driven by resource availability, such as abundant or coconuts on low-lying islands, and low predation pressure from mammalian competitors, which allow for greater growth; (mtDNA) analyses of isolated populations reveal , including distinct haplogroups that support local adaptations in body size and shape during prehistoric human-mediated dispersals.

Distribution and habitat

Native range

The Polynesian rat (Rattus exulans) is native to tropical and subtropical regions of , spanning and island Southeast Asia, with core populations in areas such as , the Moluccas, and ; it was absent from prior to human-mediated introductions. Genetic analyses of across potential native sites reveal the highest lineage diversity in island Southeast Asia, particularly in the Indo-Malayan region of eastern , supporting an origin there rather than on the mainland. Specifically, diversity peaks on in the (haplotype diversity = 0.89, nucleotide diversity = 0.19%), with ancestral lineages absent elsewhere, indicating this as the likely homeland. Fossil and subfossil evidence confirms a historical extent in dating back at least 2,000 years, including remains from Upper levels in Liang Luar Cave on (dated 2011 ± 114 BP and 1241 ± 29 BP), though earlier Pleistocene fossils are lacking in sites across , , and . These findings align with patterns pointing to an Indo-Malayan cradle, from which the species naturally dispersed within but did not cross major barriers without assistance. In its native habitats, the Polynesian rat occupies lowland forests, coastal zones, scrublands, and agricultural edges, favoring areas with good ground cover, well-drained soils, and adequate food resources, typically below 1,000 meters elevation. Pre-human distribution was constrained by oceanic barriers around island and arid deserts to the south, preventing unaided expansion to or remote Pacific archipelagos.

Introduced range and invasion history

The Polynesian rat (Rattus exulans) was introduced to Pacific islands through human-mediated dispersal by Polynesian voyagers, who transported the species via canoes as a commensal or potential source during their expansions across approximately 3,000 to 1,000 years ago. Archaeological from rat bones in early Lapita cultural sites confirms this timeline, with remains dated to around 3,500–3,000 BP in regions such as the and , including a specific site in at approximately 2,800 BP. These findings indicate that the rat accompanied the initial Austronesian migrations from into , serving as a proxy for patterns. Further spread occurred with subsequent Polynesian colonizations, reaching around 1,700–1,200 BP (circa 250–750 AD) and approximately 800 BP (circa 1200 AD) via Māori voyagers. In , rat-gnawed seeds and bones from lowland sites align with the estimated arrival of Polynesian settlers around 400 AD, while in , ancient DNA from rat remains corroborates the late 13th-century introduction. The species also dispersed to other remote islands, such as Rapa Nui (), between 1190 and 1290 CE, again tied to human voyaging. Today, the introduced range of the Polynesian rat is widespread across , , and , encompassing thousands of tropical and subtropical islands where it has established persistent populations. Invasion vectors remain predominantly , driven historically by deliberate or accidental transport during voyages and , and in modern contexts by stowaways in cargo shipments; the species lacks the ability for natural overwater dispersal due to limited swimming capabilities.

Biology and behavior

Reproduction and life cycle

The Polynesian rat (Rattus exulans) exhibits a high reproductive rate that varies by environmental conditions, breeding year-round in tropical regions with peaks during wet seasons or periods of abundant . Reproductive parameters vary with environmental conditions, such as abundance and , leading to higher rates in resource-rich tropical areas. In subtropical areas like parts of , reproduction is seasonal, occurring primarily from May to August with no breeding from to . Females are polyestrous and capable of multiple cycles annually, influenced by resource availability such as diet. Litters typically contain 3–11 young, with averages reported from 4 in field studies to 6–8 in some datasheets, and females produce 4-6 litters per year under optimal conditions. lasts 21-24 days, though it may extend by 3-7 days during concurrent . Newborns are altricial, born hairless with eyes closed, and require intensive early . They open their eyes around 2 weeks and are weaned at 3-4 weeks. is reached at 60–70 days in captivity but 8–12 months in the wild. In the wild, lifespan averages 1-2 years, though individuals may survive up to 18 months; in captivity, it extends to 4-5 years. This species' population dynamics feature a high reproductive potential, with females achieving an annual net reproductive rate supporting rapid growth under favorable conditions. Growth is density-dependent, regulated primarily through juvenile dispersal rather than reduced fecundity. Parental care is minimal, with females providing nursing for approximately 3 weeks post-birth and no involvement from males.

Diet and foraging

The Polynesian rat (Rattus exulans) is an omnivorous with a highly variable that reflects opportunistic feeding strategies adapted to island environments. Dietary composition varies by habitat; in native Hawaiian forests, dominate at approximately 83% of relative abundance, while fruits and seeds comprise about 10%, and other around 7%. In agricultural settings, such as fields, plant material can constitute up to 70% of the by volume. Preferred foods highlight the species' adaptability to Pacific island and . It readily consumes seeds and fruits from native and introduced plants, including fleshy varieties like (), passion fruit (), and (), as well as coconut husks (Cocos nucifera). Animal components feature prominently in the form of such as larvae, earthworms, spiders, slugs, and snails, which occur in over 95% of stomach samples. The rats also target eggs and occasionally scavenge carrion opportunistically, enhancing dietary diversity in coastal or seabird-colonized areas. Foraging occurs primarily at night, with individuals remaining close to burrows—typically within 30-50 meters—and focusing on ground-level searches in understory vegetation or crop edges. They cache excess food, such as seeds, in burrows to sustain periods of scarcity, and adult daily intake ranges from 3-5 grams, scaling with body size and energy needs. In human-modified landscapes, they exploit crops like taro (Colocasia esculenta) and yams (Dioscorea spp.), integrating these into their diet alongside native resources. Seasonal variations influence dietary emphasis, with greater reliance on invertebrates during lean winter periods (up to 98% occurrence) and increased herbivory on fruits and vegetation in summer fruiting seasons. These shifts underscore the species' flexibility in resource-poor island ecosystems. Digestively, the Polynesian rat possesses a cecum that facilitates hindgut fermentation of fibrous plant material, breaking down cellulose via microbial action for nutrient extraction. Gut transit is rapid, with stomach-to-cecum passage occurring in 4-6 hours, enabling efficient processing of diverse, often low-quality foods.

Social and movement patterns

The Polynesian rat ( exulans) typically exhibits a that is largely solitary or characterized by loose family groups, with evidence of in captive settings where females often dominate males and defend specific nest areas. In wild populations, breeding males maintain larger home ranges than females, averaging 0.43 acres (approximately 1,740 ) compared to 0.20 acres (approximately 810 ), suggesting territorial primarily in males, while female ranges may overlap. Aggressive interactions, such as chasing and biting, occur to reinforce dominance but appear limited in low-density wild conditions, with no observed submissive postures or territorial marking via ventral glands. Activity patterns are strictly nocturnal, with individuals remaining relatively sedentary and confining most movements to within 30–50 m of burrows, though males travel farther than females. Mean distances between captures indicate daily ranges of approximately 25–38 m, with no significant seasonal variation except during peaks in certain months. Communication involves ultrasonic vocalizations as part of a basic repertoire shared among species, along with behaviors like nosing for individual recognition and aggressive postures such as side-rising during encounters. Scent marking via contributes to signaling, particularly in reproductive contexts. Dispersal is minimal in isolated island populations, where individuals show restricted movements and limited emigration, likely due to habitat constraints. The species does not undergo true ; however, activity and body condition, including fat deposits, are reduced during non-breeding seasons such as winter or dry periods on tropical islands.

Ecological impacts

Predation on wildlife

The Polynesian rat (Rattus exulans), also known as the Pacific rat or kiore, exerts significant predatory pressure on native in island ecosystems, particularly targeting ground-nesting birds such as , shearwaters, and rails, along with their eggs and chicks, as well as like , snails, and . This predation is facilitated by the rat's adept climbing abilities, allowing access to burrows and low nests, and its keen for detecting prey, with a heightened preference for protein-rich foods like eggs and chicks during breeding seasons when nutritional demands increase. In Pacific island habitats, R. exulans predation has contributed to high chick mortality rates, often exceeding 80% on infested islands without control measures; for instance, fledging success for Cook's (Pterodroma cookii) on islands improved from 5-8% to 54-88% following rat eradications, indicating that rats alone can cause over 90% mortality in vulnerable populations. Case studies underscore these impacts: the species has been implicated in the local or total of at least 23 species in , including 10 like the gray-faced (Pterodroma gouldi) and 13 terrestrial birds such as the bush (Xenicus longipes), with predation rates documented at up to several chicks per per night in dense colonies. Similarly, in , R. exulans contributed to broader declines in lowland forest through egg and chick predation. Predation extends to invertebrates, where R. exulans depletes populations of snails, , and critical to food webs. Skinks and other also suffer, with dietary analyses on islands like Lady Alice, , showing skinks comprising part of the rat's diet alongside and wētā. Ecological models and eradication outcomes reveal that R. exulans presence correlates with 30-50% or greater declines in native on small islands, as evidenced by post-removal recoveries in fledging rates and invertebrate abundances that restore pre-invasion levels, highlighting the rat's role in driving cascading losses across trophic levels.

Habitat alteration and competition

The Polynesian rat (Rattus exulans) significantly alters island habitats through intensive , consuming a substantial portion of native seeds and hindering regeneration. On Rapa Nui (), recent modeling indicates that introduced Polynesian rats could have destroyed up to 95% of palm seeds (Paschalococos disperta), which were large and energy-rich, making them particularly vulnerable; a single breeding pair could expand to 11.2 million individuals within 47 years, rapidly overwhelming seed production and contributing to the collapse of palm populations, though human land clearance via fire accelerated the overall process. Earlier analyses of archaeological evidence, however, suggest rat predation on palm nuts was limited, with fewer than 10% showing gnaw marks, positioning rats as a secondary factor relative to human activities in the woodland's demise. This seed consumption disrupts native recruitment, particularly for trees in tropical s. Beyond direct consumption, Polynesian rats engage in competitive interactions that displace , exacerbating shifts. On Pacific islands, these rats compete with ground-foraging and remaining native for and seeds, reducing access to shared resources and contributing to declines in ; for instance, they outcompete endemic species in nutrient-poor environments, leading to localized extinctions of smaller vertebrates. Fecal deposits from high-density populations enrich soil nutrients locally, shifting microbial communities and facilitating the growth of non-native vegetation that thrives in disturbed conditions. On coral atolls like those in , such as Tetiaroa, Polynesian rats reduce native seedling recruitment by consuming fruits, seeds, and young shoots of species like Pisonia grandis and Pandanus tectorius, with post-eradication monitoring showing increases in some transects (e.g., Pisonia seedlings rising from ~380 to over 1,000 per transect); additionally, rats inadvertently disperse seeds of invasive plants like coconut (Cocos nucifera) through caching and defecation, enhancing their proliferation. These alterations culminate in long-term trophic cascades that reshape island ecosystems. By preying on seabird eggs and chicks, Polynesian rats reduce seabird populations, diminishing marine-derived nutrient inputs to soils and triggering declines in invertebrate abundance—eight of 19 orders were less prevalent on rat-invaded islands off New Zealand—which in turn lowers ecosystem complexity and indirectly impairs pollination services reliant on insect pollinators. This cascade effect propagates to vegetation, as reduced insect-mediated pollination limits plant reproduction, compounding the habitat degradation initiated by seed predation and competition.

Human interactions and conservation

Cultural and historical role

The Polynesian rat (Rattus exulans), known as kiore in , accompanied Polynesian voyagers as inadvertent stowaways on their seafaring canoes during the of the Pacific islands, serving as a commensal that arrived simultaneously with s. Archaeological from rat bones and gnawed in early settlements confirms this co-dispersal, with dates indicating arrival around 1025–1120 AD in the as part of the broader eastward expansion from central . These rats, unable to swim long distances independently, relied on human transport, highlighting their role in tracing prehistoric human across remote archipelagos. In traditional Māori society, kiore were valued as a high-protein food source and delicacy, particularly during late autumn and winter when they were in prime condition for hunting. Hunters used snares made from mānuka bark fibers to capture them, after which the rats were skinned, roasted over open fires, or cooked in hāngī earth ovens—where food is steamed using heated stones covered with leaves and earth for insulation—providing a reliable, portable protein in pre-European diets. This culinary use persisted in Polynesian cultures, underscoring the rat's practical significance beyond mere survival. Symbolically, the Polynesian rat featured in lore as a clever figure linked to and survival. In other myths, rats appeared as entities or omens, with taboos surrounding their consumption or representation; for instance, in tales like "Pikoi the Rat-Killer," rat deities wield bows and arrows, embodying cunning and familial protection, while shape-shifting rats in warned of impending events or enforced moral lessons. Archaeological analysis of Polynesian rat remains has provided key insights into human settlement timelines, with rat-gnawed seeds and bones from middens subjected to accelerator mass spectrometry (AMS) radiocarbon dating on collagen to establish precise arrival dates. On Easter Island (Rapa Nui), for example, gnawed seeds dated to around 1200 AD confirm the rats' introduction by Polynesian colonists, correlating directly with the onset of human activity and environmental changes. These methods leverage the rats' short lifespan and rapid reproduction to mark the immediate footprint of voyagers without relying solely on human artifacts. In contemporary contexts, the Polynesian rat is often perceived as an invasive pest threatening native in conservation efforts, yet it retains cultural heritage value among New Zealand (tribes), who advocate for managed harvesting to honor traditional practices. Initiatives on islands like Slipper Island explore sustainable cultural harvests, balancing ecological management with rights under the , ensuring the kiore's historical role is preserved amid modern conflicts.

Control and eradication efforts

Control and eradication efforts for the Polynesian rat ( exulans) focus on island-based operations in the Pacific, where the species is a widespread invasive. Primary methods include the use of second-generation anticoagulants like , delivered via hand- or aerial-broadcast bait (often by or ) at rates of 10–84 kg/ha to achieve comprehensive coverage. Bait stations containing diphacinone or are deployed for targeted in accessible areas, while snap traps and live traps supplement efforts for and cleanup phases. These approaches are typically followed by ecosystem restoration, such as replanting native vegetation, to facilitate recovery of colonies and other native . Aerial broadcasting has proven effective on remote, rugged terrain, as demonstrated in operations across and . Successes have been notable since the 1990s, with eradications confirmed on over 70 islands in French Pacific territories alone, including 56% of 25 monitored operations in French Polynesia and 90% in New Caledonia and Wallis. Examples include Lehua Island (Hawaii, 154 ha), declared Polynesian rat-free in 2021 after aerial brodifacoum application, resulting in a 10-fold increase in native seabird burrow occupancy within two years. Similarly, Motu Reiono (French Polynesia, 22 ha) achieved eradication in 2018 using optimized bait placement, saving significant resources while confirming no rats after 18 months of monitoring. These efforts have led to broader ecological recoveries, such as enhanced breeding success for species like the Tuamotu sandpiper (Prosobonia cancellata) on rat-free atolls. Globally, over 500 rodent eradications have occurred, many targeting Polynesian rats in the Pacific, contributing to the restoration of island biodiversity. Key challenges stem from the species' rapid reproduction—females can produce up to six litters per year with 3–6 young each—requiring 100% mortality for full eradication, as even one surviving pregnant female can repopulate an island within a year. Reinvasion risks are high via swimming (up to 500–1,000 m) or human-mediated transport from nearby infested sites, necessitating ongoing . Non-target impacts include secondary poisoning of seabirds and from bait or rodent carcasses, as observed in post-operation where residues persisted in ecosystems for years. Failure rates on tropical islands reach 10–44%, often due to incomplete bait uptake by crabs or uneven . Integrated approaches combine and with preventive measures like strict protocols at ports and airports to block new introductions, alongside modifications such as clearing dense to expose rats. Genetic monitoring using aids early detection of survivors or reinvaders. Costs vary by island size and logistics, ranging from approximately $1 million for small sites like to $2–5 million for larger atolls like Tetiaroa, covering , , and multi-year . International initiatives, led by the IUCN Species Survival Commission's Invasive Species Specialist Group and organizations like Island Conservation, provide best-practice guidelines emphasizing multi-stakeholder planning and . These programs have facilitated over 800 global eradication attempts since 1960. Future tools, including CRISPR-based drives to induce or population suppression, remain experimental but show promise in lab trials on rats, potentially enabling mainland applications beyond islands.

References

  1. [1]
    GISD
    ### Summary of Polynesian Rat (Rattus exulans) - IUCN GISD
  2. [2]
    None
    ### Summary of Rattus exulans (Polynesian Rat) from Witmer et al. 2018, UNL Digital Commons
  3. [3]
    Polynesian Rat - Rattus exulans - Ecology Asia
    Rattus exulans (Polynesian Rat, Pacific Rat) is a commensal species, closely associated with man: it is commonly found in the vicinity of houses, farms and ...Missing: scientific biology
  4. [4]
    Invasive rats on tropical islands: Their population biology and ...
    exulans have been incrementally introduced to islands as humans have explored the world's oceans. They have caused serious deleterious effects through predation ...
  5. [5]
    Rattus exulans (Pacific rat) | CABI Compendium
    May 15, 2014 · The Pacific rat, R. exulans, is an major agricultural and environmentalpest in parts of Southeast Asia and the Pacific.
  6. [6]
    micro-evolution in Polynesian rats highlights body size changes as ...
    Apr 28, 2020 · The Polynesian rat (Rattus exulans) is an excellent proxy species because of its wide geographic and temporal distribution: its native and ...<|control11|><|separator|>
  7. [7]
    Rattus exulans - Global Invasive Species Database
    Oct 4, 2010 · The Pacific rat (Rattus exulans) is the smallest of the three rats (Rattus rattus, R. norvegicus and R. exulans) closely associated with humans.
  8. [8]
    Rattus exulans - Pacific Rat - Cook Islands Biodiversity
    COMMON NAMES: Pacific Rat, Polynesian Rat ; TRADITIONAL NAMES: Kiore / Kiore Toka (RR), Kiore (MG AT MK MT AK TW), Rat (PL), Kiole (TS PK NS); Other Polynesian - ...
  9. [9]
    Polynesian rat - Wiktionary, the free dictionary
    Synonyms: kiore, Maori rat, Pacific rat. Translations. ±Rattus exulans. [Select preferred languages] [Clear all]. Dutch: Polynesische rat (nl); Hawaiian: ʻiole ...
  10. [10]
    Rattus exulans (Peale, 1848) - GBIF
    Rattus exulans (Peale, 1848) ; Dataset; GBIF Backbone Taxonomy ; Rank; SPECIES ; Published in; Mammalia in Repts. U.S. Expl. Surv. vol.8 p.47 ...
  11. [11]
    Rattus exulans (Peale, 1848) - Plazi TreatmentBank
    Nov 23, 2024 · Taxonomy. Mus exulans Peale, 1848 ,. Tahiti Island (France), Society Islands. Rattus exulans is in the exulans species group, which is sister to ...
  12. [12]
    [PDF] The Polynesian Society
    Oct 11, 2025 · The Māori story of the kiore (Polynesian rat, Rattus exulans) and the pōwhaitere (parakeet, Cyanoramphus sp.) differs from the previous two.<|control11|><|separator|>
  13. [13]
    Managing for cultural harvest of a valued introduced species, the ...
    Aug 3, 2021 · Although relationships with kiore are recorded in oral tradition ... Population ecology of Polynesian rat, Rattus exulans, on Kure Atoll, Hawaii.
  14. [14]
    Rattus exulans (Polynesian rat) - Animal Diversity Web
    Class, Mammalia mammals ; Order, Rodentia rodents ; Family, Muridae Old World mice and rats, gerbils, whistling rats, and relatives ; Genus, Rattus New Guinea rats.
  15. [15]
    Steven Miller - New Zealand Rattus spp. Identification Table
    Rattus spp. Identification Details ; Tail, Slightly shorter or longer than HBL; Thin and uniformly dark all over. Much longer than HBL; Uniformly dark all over.
  16. [16]
    Dental Anatomy of Rodents
    Dental Formula for Mice and Rats. Permanent, 1 0 0 3 1 0 0 3, = 8. Maxillary Arcade. Maxillary Arcade (lateral liew). Mandibular Arcade. Mandibular Arcade ( ...Missing: exulans | Show results with:exulans
  17. [17]
    Growth and Development of Rattus exulans | Journal of Mammalogy
    Abstract. Growth and development were studied in the Polynesian rat, Rattus exulans, at Kure Atoll, Hawaii, and in the laboratory. Reproduction is seasonal.<|separator|>
  18. [18]
    [PDF] Population Ecology of the Polynesian Rat, Rattus exulam, on Kure ...
    ABSTRACT: A population of the Polynesian rat, Rattus exulans, was studied at. Green Island, Kure Atoll, in the northwestern Hawaiian Islands from September.
  19. [19]
    Changing Invaders: trends of gigantism in insular introduced rats
    Here, I present data from an ubiquitous invasive species, the Polynesian rat (Rattus exulans), which provides an excellent proxy to measure and model ...
  20. [20]
    Changing invaders: trends of gigantism in insular introduced rats
    Mar 14, 2018 · The dispersal of the Polynesian rat (Rattus exulans) has been facilitated by humans since prehistoric times. Populations in Oceania were ...
  21. [21]
    micro-evolution in Polynesian rats highlights body size changes as ...
    Apr 28, 2020 · The Polynesian rat (Rattus exulans) is an excellent proxy species because of its wide geographic and temporal distribution: its native and ...<|control11|><|separator|>
  22. [22]
    Molecular Genetic Evidence for the Place of Origin of the Pacific Rat ...
    Mar 17, 2014 · We conducted a mitochondrial DNA phylogeographic survey of R. exulans diversity across the potential natural range in mainland and Island Southeast Asia
  23. [23]
    Molecular Genetic Evidence for the Place of Origin of the Pacific Rat ...
    We conducted a mitochondrial DNA phylogeographic survey of R. exulans diversity across the potential natural range in mainland and Island Southeast Asia
  24. [24]
    Rattus exulans - Global Invasive Species Database
    Oct 4, 2010 · Rattus exulans is recognised as a predator of native insects, lizards and birds, a browser of native flora and an agricultural pest.
  25. [25]
    [PDF] Polynesian Rats - UNL Digital Commons
    The Polynesian rat is not present in the mainland United. States. Habitat. In Hawaii, Polynesian rats are most common below 2,500 feet (750 m) elevation, ...
  26. [26]
    [PDF] Abundance and Diets of Rats in Two Native Hawaiian Forests1
    Black rats ate more fruits, seeds, and other vegetation than did Polynesian rats. More information about the life history, ecology. and behavior of rats in ...Missing: sources | Show results with:sources
  27. [27]
    [PDF] Dietary niche differentiation among three species of invasive rodents ...
    Nov 29, 2012 · Identifying items in stomachs of introduced rodents helps determine rodents' trophic positions and species most at risk of consumption. In the ...
  28. [28]
    [PDF] DNA metabarcoding reveals diet composition of invasive rats and ...
    Identifying the composition of invasive rodent diets can clarify complex interac- tions with native and introduced species and help conservation practitioners ...
  29. [29]
    [PDF] Rat-Feeding Injury to Plants in Hawai'i - CTAHR
    Jun 7, 2012 · The Polynesian rat causes significant damage to sugarcane, pineapple, macadamia nuts (Macadamia integrifolia), coconuts (Cocos nucifera), ...Missing: taro | Show results with:taro<|control11|><|separator|>
  30. [30]
    Dietary shift of an invasive predator: rats, seabirds and sea turtles
    Dec 6, 2007 · Our results suggest a heavy predatory impact on seabirds, which could constitute as much as 24% of the rat diet.Missing: Polynesian pandanus carrion
  31. [31]
    [PDF] Reassessing the Role of Polynesian Rats (Rattus exulans) in Rapa ...
    Jun 8, 2025 · Henderson Island mortality ranges from 0.352 to 0.950 within a single season, potentially strongly regulating population growth rate (Oppel et ...
  32. [32]
    Rat Study Offers Clues to Island Ecology - Archaeology Magazine
    Jun 7, 2018 · ... plants, such as breadfruit, yam, and taro, in the rats' diets. Levels of nitrogen isotopes provide evidence of the balance of land-based and ...Missing: seasonal | Show results with:seasonal
  33. [33]
    Acidic fermentation in the caecum increases absorption of calcium ...
    Mar 9, 2007 · An analysis of intestinal calcium transport across the rat intestine. American Journal of Physiology 250, G561–G569.Google ScholarPubMed.
  34. [34]
    Adaptation of hydrogen analysis to measure stomach to caecum ...
    Excreted hydrogen analysis was used to measure stomach to caecum transit time of the head of a test meal in 120 rats fed by gavage.Missing: exulans | Show results with:exulans
  35. [35]
    https://pacificrimconservation.org/wp-content/uploads/2023/09/s10530-023-03159-4.pdf
  36. [36]
    Population Ecology of the Polynesian Rat, Rattus exulans, on Kure ...
    Title: Population Ecology of the Polynesian Rat, Rattus exulans, on Kure Atoll, Hawaii. Authors: Wirtz, William O. II. LC Subject Headings: Polynesian rat.Missing: regional names Tahiti Maori
  37. [37]
    [PDF] lessons from Pacific rat (Rattus exulans) removals on New Zealand ...
    Dec 2, 2008 · All of them were within or less than the body weight (100–180 g) of ship rats (Innes. 2005). Other species appeared unaffected and some.
  38. [38]
    Rattus exulans and the catastrophic disappearance of Hawai'i's ...
    Aug 5, 2025 · An entire issue of Biological Invasions was devoted to the impacts of rats on island populations -see Drake and Hunt (2009) and the other papers ...
  39. [39]
    https://archaeology.org/news/2018/06/07/180607-polynesia-rat-diets/
  40. [40]
    https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/acidic-fermentation-in-the-caecum-increases-absorption-of-calcium-and-magnesium-in-the-large-intestine-of-the-rat/D78E5E94C26E01A30B307C518A466CF2
  41. [41]
    https://pubmed.ncbi.nlm.nih.gov/3653753/
  42. [42]
    Report Invasive rat drives complete collapse of native small mammal ...
    Jul 11, 2022 · Our results suggest that insular forest fragments are highly susceptible to rapid species loss, particularly due to the competitive nature of Rattus.
  43. [43]
    [PDF] Pacific Rat Risk Assessment
    exulans is obscure, but it is probably native to South-East Asia. R. exulans is an invasive pest on numerous islands across the Pacific, where it has.
  44. [44]
    [PDF] four years (2018-2021) monitoring of seedling recruitment before ...
    The goal of this study was to conduct a multi-years monitoring of plant seedling recruitment. (mainly native and woody species) in permanent transects and ...
  45. [45]
    Rat Genes Tell Human Migration History | Science | AAAS
    Rat Genes Tell Human Migration History ... Share: ... When people first sailed around the islands of Polynesia some 3500 years ago, rats often went along for the ...Missing: companion | Show results with:companion
  46. [46]
    Dating the late prehistoric dispersal of Polynesians to New Zealand ...
    We show how the earliest-dated evidence of the introduced commensal Pacific rat (Rattus exulans) can be used as a reliable proxy to pinpoint the time of initial ...<|separator|>
  47. [47]
    Patterns of prehistoric human mobility in Polynesia indicated by ...
    Therefore, although there may have been multiple introductions of the Polynesian rat from the Marquesas and the Society and Southern Cook Islands, we are unable ...
  48. [48]
    Traditional Māori food gathering | Te Papa
    The kiore were usually in good condition for catching and eating during late autumn and winter, and were a high-protein delicacy. Waka kererū (pigeon snare).
  49. [49]
    Kiore - Science Learning Hub
    Sep 10, 2024 · Kiore is one species (Rattus exulans), also known as the Polynesian rat or Pacific rat, which is the smallest of the Rattus genus.
  50. [50]
    Hawaiian Legends Index - University of Hawaii at Manoa
    Subject: Rats appears in the legend: "Pikoi the Rat-Killer" in the book: Westervelt, W. D., Hawaiian Legends of Old Honolulu on pages: 157-172. HSL Call ...Missing: navigation omens trickster
  51. [51]
    XXI. Pikoi the Rat-killer | Sacred Texts Archive
    These "gods" were all rats and were named "Kikoo," which was the name of the bow used with an arrow for rat-shooting. They were "Bow-of-the-heaven," "Bow-of-the ...
  52. [52]
    Dating the late prehistoric dispersal of Polynesians to New Zealand ...
    Jun 3, 2008 · Radiocarbon dates on distinctive rat-gnawed seeds and rat bones show that the Pacific rat was introduced to both main islands of New Zealand ...Missing: Society Easter
  53. [53]
    [PDF] Successes and failures of rat eradications on tropical islands
    Except for the Wake project that targeted Pacific rat (R. exulans) and Asian house rat. (R. tanezumi), the eradication operations targeted the removal of just ...Missing: stories | Show results with:stories
  54. [54]
    [PDF] Invasive rodent eradications in French Pacific islands - Archimer
    Proceedings of the Vertebrate Pest Conference 29,3. 652. Harper GA, Bunbury N (2015) Invasive rats on tropical islands: their population biology and. 653.
  55. [55]
    [PDF] Rat Control for the Protection of Endangered Birds, Plants, and Tree ...
    Since 1997, the OANRP has primarily controlled rats through the use of diphacinone bait blocks in bait stations in combination with rat traps in close proximity ...
  56. [56]
    04/21/21-SUCCESS! LEHUA ISLAND IS RAT FREE
    Apr 21, 2021 · Lehua Island, the tiny, but mighty island off Kaua'i's west shore has been declared free of damaging, introduced (invasive) rats.Missing: cost | Show results with:cost
  57. [57]
    Rats took over this Pacific island. Now drones are leading ... - WIRED
    Jul 16, 2021 · ... Polynesians introduced R. exulans (the Polynesian rat) to Tetiaroa atoll – a six-kilometre-square island in French Polynesia – around 1,000 ...Missing: Mauritius | Show results with:Mauritius
  58. [58]
    [PDF] Review of rat invasion biology: implications for island biosecurity
    Rats invade islands by ship and swimming, with Norway rats swimming up to 1km. Multiple detection methods are needed, including poisons, traps, and dogs.
  59. [59]
    [PDF] Brodifacoum residues in fish three years after an island-wide rat ...
    Jan 27, 2020 · Invasive rats are known to threaten natural resources and human health and safety. Island-wide rat eradication attempts have been increasing in ...Missing: stories | Show results with:stories
  60. [60]
    State Proceeds with Lehua Island Rat Eradication - Maui Now
    Aug 23, 2017 · The state Department of Land and Natural Resources began aerial application of rodenticide today in an attempt to control the rat population at Lehua Island.Missing: cost | Show results with:cost
  61. [61]
    What are the concerns about the Lehua Island rat eradication plan?
    Jul 25, 2017 · According to Samuels, it will cost an estimated $1.5 million to $2 million to get rid of the rats. He expressed appreciation to the business ...
  62. [62]
    https://www.wired.com/story/rat-pacific-island-drones/
  63. [63]
    Gene Drive: A Tool for Conservation?
    Jul 27, 2017 · Gene drive could help conservationists prevent extinctions of seabirds and island species. Invasive rodents have significant negative impacts on ...