Amami rabbits are predated upon by feral dogs and cats from encroaching human populations. Amami rabbits are potentially more susceptible to predation by feral cats because of the ability of cats to climb the mountainous slopes of Amami Island. The main predator of these rabbits are exotic mongooses (Herpestes javanicus), which were introduced to Amami Island to kill venomous habu snakes (Protobothrops flavoviridis) in 1979, but has since become a bigger problem than the native snakes. Mongooses are an effective generalist predator of many terrestrial animals, such as Amami rabbits. Some small animal populations increased in the presence of mongooses, due to trophic cascade effects (mongooses ate the middle level predators, which normally preyed upon the smaller species) but most small mammals (including P. furnessi), dramatically decreased in areas where mongooses were present.
Amami rabbits are known to run away when approached by humans and make vocalizations when predators are nearby.
Known Predators:
Amami rabbits have an average body length of 451 mm in males and 452 mm in females. Their tail lengths range from 20 to 35 mm in males and 25 to 33 mm in females. Amami rabbits are slightly sexually dimorphic, females tend to be larger. The average mass of rabbits found in the wild was 2.2 kg for males and 2.5 kg for females, while some rabbits measured in captivity weighed 2.1 kg (± 0.27 kg standard deviation) for males and 2.2 kg (± 0.12 kg standard deviation) for females. The largest mass measured was 2.9 kg in a female and the smallest mass was 2.0 kg in a male.
Amami rabbits are very primitive mammals with thick, dark brown or black fur, short ears (45 mm), small eyes and large claws (up to 20 mm long). In fact, the oldest found Pentalagus furnessi fossil is estimated to be from the last ice age (30,000 to 18,000 years ago). The fossil was identified by the characteristic loopy enamel pattern of Pentalagus molars. The dental formula for P. furnessi is 2/1 incisors, 0/0 canines, 3/2 premolars, and 3/3 molars, for a total of 28 teeth. Their foramen magnum is a smaller, horizontal oval compared to the vertical oval or pentagonal shape of genus Lepus. Their supraorbital process does not have any projections. Their basal metabolic rate of P. furnessi is not known.
Range mass: 2030 to 2880 g.
Average mass: 2253.25 g.
Range length: 397 to 530 mm.
Average length: 451 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: female larger
The longevity and lifespan of P. furnessi is unknown.
Amami rabbits live in forested areas and use tree hollows and burrows for cover during the day. They live in both new and old growth forests and have been found in some grassland habitats consisting of ferns and perennials. Due to the number of fecal pellets found, it has been suggested that Amami rabbits may frequent forested locations near waterways more often than other areas.
Amami Island is subtropical and approximately 85% of the island is forest. Tokuno Island is approximately 44% forested, both islands have mountainous topography. The tallest mountains on Amami and Tokuno have an elevation of 694 m and 645 m, respectively. The average annual temperature of Amami is 21.5°C. The Amami forest is considered “rainforest” because of the high annual rainfall (2871 mm per year), the predominance of tall, broad-leaf trees and the poor agricultural soil conditions that result from those factors.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: savanna or grassland ; forest ; rainforest
Other Habitat Features: riparian
Members of genus Pentalagus are considered quite primitive in their characteristics and are classified in the family Leporidae with other monotypic primitive rabbit species, such as genus Romerolagus and genus Pronolagus. Genus Pronolagus may be their closest extant genus, however, other studies suggest that classification was based on morphological and not molecular characteristics. Using RNA sequences, P. furnessi appears to be more closely related to Romerolagus diazi, but when using cytochrome b sequences, it appears to be more closely related to Bunolagus monticularis.
Regardless of the phylogeny, it is accepted that P. furnessi is a very basal species, having found fossils from the last ice age (30,000 to 18,000 years ago), as well as more recently in Japan’s history (the Jomon Period, 2500 to 300 BC).
Pentalagus furnessi communicates with auditory signals, mainly vocalizations and sounds are made by pounding their hind limbs against the ground. Signals are produced when predators or humans enter the area or to let young know the mother has returned to the nest.
Pentalagus furnessi makes calls that are similar to those made by pikas, with 3 to 4 short calls (0.4 to 0.6 seconds), 6 to 12 KHz in frequency.
Communication Channels: acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Pentalagus furnessi is considered endangered by the International Union for Conservation of Nature (IUCN) Red List because of its occurrence in areas less than 10 km2. Amami rabbits are known to inhabit only one location (the Nansei Archipelago) and they are expected to have a continued decline in area, habitat and number of individuals.(IUCN for more information) Pentalagus furnessi has no special status on the Convention on International Trade in Endangered Species (CITES) list. Amami rabbits were declared a Special National Monument by the government of Japan in 1963, meaning that hunting and trapping is banned. However, most of their habitat is still being cleared for use by the paper industry. Rotating the forests that are cut down to promote growth of secondary forests could help alleviate this pressure.
Their current population size, estimated on fecal matter counts on the islands, is 2,000 to 4,800 on Amami Island and 120 to 300 on Tokuno Island. These rabbits are estimated to have declined from a population of 2,500 to 5,800 in 1986. Nagata et al. (2009) suggest that microsatellites could be used in future studies to determine their population size.
US Federal List: endangered
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: endangered
Pentalagus furnessi has little negative economic importance to humans.
Pentalagus furnessi has little positive economic importance to humans.
Amami rabbits are primary consumers of plant material and are prey for small Asian mongooses, feral cats and dogs.
Various species of parasitic worms use the stomach and digestive system of Amami rabbits as a host including Obeliscoides pentalagi, Ogmocotyle and Eimeria.
Commensal/Parasitic Species:
Pentalagus furnessi is thought to eat grasses and ferns, such as South American elephant grass and Dicranopteris pedata, respectively. In captivity, P. furnessi were seen eating the acorns of Castanopsis sieboldii, a broad-leafed evergreen tree of Amami Island.
Amami rabbits may be coprophagic. The fecal matter they ingest is softer and less fibrous than their other pellets.
Plant Foods: leaves; seeds, grains, and nuts
Other Foods: dung
Primary Diet: herbivore (Folivore , Granivore ); coprophage
Amami or Ryuku rabbits (Pentalagus furnessi) are found exclusively on the Amami and Tokuno Islands of the Nansei archipelago, a group of islands off the southwestern coast of Japan that were separated from the mainland some 1.5 million years ago. Amami Island (28°20’ N, 129°14’ E) is one of the largest of the chain, with an estimated area of 710 km2 to 820 km2, if the immediately adjacent islands are included. Tokuno Island is smaller, with an area of about 250 km2.
Biogeographic Regions: palearctic (Native ); pacific ocean (Native )
Other Geographic Terms: island endemic
Amami rabbits may be promiscuous (polygynandrous) because the male home ranges overlap with the female home ranges. It is not known whether a single male mates with more than one female, if a female mates with more than one male or if they both mate with more than one partner. During mating in captivity, male rabbits approach females, lift the female’s abdomen with their nose or bite the female’s legs during copulation.
An attempt to breed Amami rabbits in captivity did produce one offspring. This neonate had a birth mass of 100 g and was approximately 15 cm long. It had an ear length of 1.5 cm and its tail was 0.5 cm in length. Forelimbs and hind limbs were 1.5 cm and 3.0 cm, respectively.
Another attempt to breed Amami rabbits in captivity produced 11 offspring over the course of 5 years at Kagoshima Hirakawa Zoo, in Japan. Birth of neonates occurred in spring and fall, so it is suggested that Amami rabbits breed throughout the year, or in at least two seasons.
Length of gestation is unknown for P. furnessi, but a closely related primitive Leporid species, Romerolagus diazi (volcano rabbits), has a gestation period of 39 days.
Breeding interval: Amami rabbits may breed twice a year.
Average number of offspring: 1.
Range time to independence: 3 to 4 months.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Pentalagus furnessi is said to have two separate nests, one for daily activity and one for delivery and care of the offspring. Females dig the birthing burrow approximately one week before birth. The burrow is about 30 cm across and filled with leaves. The mother leaves the nest for about 24 hours and hides the entrance with soil, leaves and sticks. The mother is known to give a short call, alerting the young of its return to the burrow. Female Amami rabbits have three pairs of mammary glands, but it is not known how long they nurse their young.
After about 3 to 4 months, females block their young from their burrows. Although they are independent at 3 months, their age of sexual maturity is unknown.
Parental Investment: female parental care ; pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)
The Amami rabbit (Pentalagus furnessi; Amami: [ʔosaɡi]), or Amami no-kuro-usagi (アマミノクロウサギ 奄美野黒兔, lit. "Amami wild black rabbit"), also known as the Ryukyu rabbit is a dark-furred rabbit which is only found in Amami Ōshima and Toku-no-Shima, two small islands between southern Kyūshū and Okinawa in Kagoshima Prefecture (but actually closer to Okinawa) in Japan. Often called a living fossil, the Amami rabbit is a living remnant of ancient rabbits that once lived on the Asian mainland, where they died out, remaining only on the two small Japanese islands where they live today.[3]
Pentalagus is thought to be a descendant of Pliopentalagus, known from the Pliocene of China and Eastern to Central Europe.[4]
The Amami rabbit feeds on over 29 species of plants, which incorporates 17 species of shrubs and 12 species of herbaceous plants, consuming mostly the sprouts, young shoots and acorns.[5] It also eats nuts and cambium of a wide variety of plant species.[6] It is observed that the Amami rabbit also feeds on the bark of stems and twigs of shrub plants.[6] During summer, the Amami rabbit primarily feeds on Japanese pampas grass, and during winter, they primarily eat the acorns of the pasania tree.[7] The Amami rabbit also eats the fruits of Balanophora yuwanensis, a parasitic flowering plant, for which they are the main distributors of seed.[8]
The Amami rabbit has short feet and hind legs, a somewhat bulky body, and rather large and curved claws used for digging and sometimes climbing.[9] Its ears are significantly smaller compared to those of other hares or rabbits.[10] The pelage is thick, wooly and dark, brown on top and becomes more reddish-brown on the sides.[11] It has heavy, long and very strong claws, being nearly straight on the forefeet and curved on the hindfeet [11] The eyes are also small compared to more common rabbits and hares. The average weight is 2.5–2.8 kg.[12]
The ideal habitat for these rabbits is in an area between mature and young forests.[13] They use the dense mature forests as protection and for the presence of pampas grass, in the summer, and acorns, in the winter, for their diets.[14] They also use the high density of perennial grasses and herbaceous ground cover in the young forests for their diets during different times of the year.[2][15] Therefore, the best habitat for them to live in is where they have easy access to both young and mature forests with no obstructions between the two forest types.[16]
Using fecal pellet counts and resident surveys, the number of rabbits is estimated at 2000–4800 left on Amami Island and 120–300 left on Tokuno Island.[13]
This species is a nocturnal forest-dweller that reproduces once in late March–May and once in September–December, having one or two young each time.[2] During the day, the mother digs a hole in the ground, for her young to hide in. At night, she opens the entrance to the hole, while watching for predators (such as venomous snakes), and then nurses her young, after which she closes the hole with soil and plant material by thumping on it with her front paws.[17] Amami rabbits sleep during the day in hidden locations, such as caves.[18] They are also noted for having a call similar to that of a pika.[12]
Before 1921, hunting and trapping were another cause of decline in population numbers. In 1921, Japan declared the Amami rabbit a "natural monument" which prevented it from being hunted.[11] Then in 1963, it was changed to a "special natural monument" which prevented it from being trapped as well.[16]
Habitat destruction, such as forest clearing for commercial logging, agriculture space, and residential areas, is the most detrimental activity on the distribution of these rabbits.[19] Since they prefer a habitat of both mature and young forests, they do not thrive in only mature forests untouched by destruction, yet they do not thrive in newly growing forests alone, either.[16] There are plans to remove the current habitat for these rabbits for the construction of golf courses and resorts, which is allowed because it will not directly be killing the rabbit, just changing the environment where it dwells, which is legal even under the protection of the special natural monument status.[20]
The Amami rabbit also faces huge threats from the invasive predators, being a major cause for the decline in population size.[2] On the island of Amami, the small Indian mongoose (Herpestes javanicus) was released to control the population of a local venomous snake, and its numbers have increased dramatically.[21] This mongoose, along with feral cats and dogs, are outpreying the Amami rabbit.[16] Feral cats and small Indian Mongooses proved to be a threat to not only Amami rabbits but several other endangered endemic species in the area such the Amami jay.[22]
In July 2008, the Amami Rangers for nature conservation obtained a photograph of a feral cat carrying a rabbit corpse (rabbit bones and fur found in cat or dog droppings had already been found), prompting discussions on better ways to control pets.[17] A small area of the Amami Island has the Amami Guntō National Park that further protects the population.[23] Some attempt at habitat restoration has been made, but the Amami rabbit needs a mosaic of mature and young forest in close proximity, and when a young forest is regrown nowhere near a mature forest, this rabbit is not likely to inhabit it.[17] Research and population monitoring also is underway to try to keep the numbers from declining, even if they can not be increased.[16]
Suggested conservation work for the future includes habitat restoration and predator population control, as a healthy balance of mature and young forests still exists on the southern end of Amami. Restricting logging would also help to keep more forest available for the rabbits to live in by leaving more forest standing, as well as disturbing the surrounding environment more.[9] An end to the building of forest roads used for logging and travel would further protect the Amami rabbit, as they cause population and habitat fragmentation, destroys their prime habitat and allows predators easier access to the middle of forests where a majority of the rabbit population exists.[2] Controlling the populations of mongooses, feral dogs, and feral cats is another approach that could help bolster the rabbit population.[9] Eradication of the mongooses and feral cats and dogs is needed, as well as better control of pets by local island residents.[16]
The Lagomorph Specialist Group of the International Union for the Conservation of Nature and Natural Resources proposed a plan of conservation in 1990.[9] In Amami-Oshima Island, the Amami Wildlife Conservation Center of the Ministry of the Environment was established in 1999.[11] It restarted a mongoose eradication program in 2005 and designated the Amami rabbit as endangered in 2004 for Japan.[12]
{{cite journal}}: CS1 maint: multiple names: authors list (link) The Amami rabbit (Pentalagus furnessi; Amami: [ʔosaɡi]), or Amami no-kuro-usagi (アマミノクロウサギ 奄美野黒兔, lit. "Amami wild black rabbit"), also known as the Ryukyu rabbit is a dark-furred rabbit which is only found in Amami Ōshima and Toku-no-Shima, two small islands between southern Kyūshū and Okinawa in Kagoshima Prefecture (but actually closer to Okinawa) in Japan. Often called a living fossil, the Amami rabbit is a living remnant of ancient rabbits that once lived on the Asian mainland, where they died out, remaining only on the two small Japanese islands where they live today.
