Japanese hares are endemic to Japan. They are commonly found on the mainland islands of Honshu, Shikoku and Kyushu and most of the surrounding Japanese islands, excluding Hokkaido. There are four subspecies of the Japanese hare found in different geographical regions. Lepus brachyurus angustidens is found in northern Honshu, L. b. lyoni is found on Sado Island, L. b. brachyurus is found in southern Honshu, and L. b. okiensis is found on the Oki Islands. (Numone, et al., 2010; Saito and Koike, 2009; Shimano, et al., 2006)
- Other Geographic Terms
- island endemic
Japanese hares can be found throughout Japan in urban, rural and forest settings, but the vast majority are found in rural areas. They are typically found in areas with dense shrub-like vegetation and a low tree canopy, often near the edge of forests. Japanese hares are predominant in young, Japanese cedar plantations where there is plenty of incoming light and an abundance of vegetation. Japanese hares are also found near and around rivers or streams. They range from sea level to 2700 m. Japanese hares do not inhabit mountainous areas. (Angermann and Flux, 1990; Enari and Sakamaki, 2012; Saito and Koike, 2009; Saito and Koike, 2013; Shimano, et al., 2006)
- Range elevation
- 0 to 2700 m
- 0.00 to 8858.27 ft
Adult Japanese hares are mid-size mammals with body masses ranging from 1.3 to 2.5 kg. There are variations in color from a dark brown to a red brown with areas of white. All four subspecies are brownish in the summer, but L. brachyurus angustidens and L.b.lyoni change their coat colors to white in the winter. (Angermann and Flux, 1990; Numone, et al., 2010; Saito and Koike, 2009)
Like all members of the Order Lagomorpha, Japanese hares have a second set of incisors, or peg teeth, behind their first upper incisors. All hares have dental formula of i 2/1, c 0/0, p 3/2, m 3/3. (Chapman and Flux, 1990)
There are variations between Japanese hare subspecies found on the main island and those found on surrounding islands. The dimensions of a mainland female Japanese hare described in 1905 were 505 mm head and body length, 40 mm tail length, 135 mm hindfoot length and 78 mm ear length. Measurements from a female Japanese hare from Oki Island were a 506 mm head and body length, a 54 mm tail, a 138 mm hind foot and a 78 mm ear. The subspecies found on the smaller islands appear to have sexual dimorphism, with the vast majority of skull characteristics being smaller in males than in females. On the main island, the only feature that is not equal in size is the width of the palate. In general, the subspecies on the small islands are often larger in mass, length of head, and length of body. The subspecies on the main island have larger ears, hind feet length and skull size compared to those on the islands. It has been suggested that this variation is not due to insular variation, but that the island forms are actually closer to the ancestral form and the main island subspecies has evolved and adapted to a changing environment. (Hirakawa, 1994; Thomas, 1905)
- Sexual Dimorphism
- sexes alike
- female larger
- Range mass
- 1.3 to 2.5 kg
- 2.86 to 5.51 lb
- Average length
- 505 mm
- 19.88 in
Nothing is known about Japanese hare mating systems. There is, however, generalizable information regarding other species of hares. Aside from arctic hares, which pair each breeding season, most male and female hares are promiscuous. Male and female hares come together during the breeding season and males sometimes display aggressive behavior, such as boxing, in order to compete for mates. (Chapman and Flux, 1990; Lumpkin and Seidensticker, 2011; Murray, 2003)
Japanese hares have a long breeding season, beginning in early January and ending in August. The number of litters per season ranges from 4 to 5. The average litter size ranges from one to four, with 1.6 babies being the average and the average weight of the young at birth is 132 g. There is a 1:1 ratio of males to females born in each litter. Within one breeding season, a typical female will average 7.4 young. The weaning period typically takes place 2 to 3 weeks after birth. (Angermann and Flux, 1990; Takeda, et al., 1994)
Female hares become sexually mature at ten months old. The gestation period ranges from 43 to 45 days and the period between births ranges from 33 to 109 days. An interbirth period shorter than the gestation period suggests the possibility of superfoetation. This is further supported by the occurrence of postcoital ovulation in Japanese hares. At the other end of the spectrum, there can also be delays between birth and the next copulation. Sometimes female Japanese hares will chase away males with whom they do not want to copulate. (Angermann and Flux, 1990; Takeda, et al., 1994)
There is some variability in breeding patterns between northern and southern Japanese hares as breeding appears to be affected by temperature, photoperiod, and precipitation. Environments in higher latitudes have decreased temperature and photoperiods throughout the majority of the year and studies of captive animals have found that with increasing latitude, the breeding season, gestation period and litter size decreases. (Takeda, et al., 1994)
- Key Reproductive Features
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- post-partum estrous
- Breeding interval
- Breeding interval is between 33 and 109 days.
- Breeding season
- Breeding occurs from January to August.
- Range number of offspring
- 1 to 4
- Average number of offspring
- Range gestation period
- 43 to 45 days
- Range weaning age
- 2 to 3 weeks
- Average age at sexual or reproductive maturity (female)
- 10 months
Nothing is known about parental care in Japanese hares, however the young of other hares are precocial and have limited parental care and this can be inferred for Japanese hares. (Angermann and Flux, 1990; Murray, 2003)
- Parental Investment
Japanese hares do not live longer than 4 years in the wild. (Saito and Koike, 2009)
- Range lifespan
- 4 (high) years
- Range lifespan
Japanese hares are solitary and nocturnal. They do not burrow, but will hide in the scrub or brush during the daytime. When they are active at night, they can travel about 1000 m in a single night in forested areas and can cover approximately 6 hectares. (Enari and Sakamaki, 2012; Saito and Koike, 2009)
The home ranges of Japanese hares are 10 to 30 hectares in size. (Enari and Sakamaki, 2012)
Communication and Perception
While nothing is known about communication between Japanese hares, information may be inferred from other hare species. There appears to be various types of vocalizations, mostly high-pitched, that occur when hares are confronted with uncomfortable or frightening situations. Like other hares, hearing is an important mode of perception. (Chapman and Flux, 1990; Murray, 2003)
- Communication Channels
Japanese hares are opportunistic herbivores that typically eat newly planted grasses, grasses at plantations, and young trees and shrubs. Saito and Koike (2009) determined that their main source of food during the summer comes from the Family Gramineae, which includes the grasses and many commercial crops. In northern Japan, when these grasses are unavailable due to winter snow cover, Japanese hares eat the buds and seedlings of young trees, often found in plantations. Tori and Suzuki (1996) examined which trees were favored in the winter and concluded that the vast majority of trees were Phyllostachys praecox, a bamboo which is high in crude protein content. Other popular winter trees include Acer, Paulownia, Acanthopanax, Aralia and Leguminosae. The trees and shrubs chosen by Japanese hares often have increased amounts of branches and stems, which are typically found in young forests. Most of the trees that are consumed have high protein content. (Angermann and Flux, 1990; Enari and Sakamaki, 2012; Hirakawa, 1994; Saito and Koike, 2009; Saito and Koike, 2013; Shimano, et al., 2006; Shimizu and Shimano, 2010)
Japanese hares also engage in coprophagy, or the reingestion of feces. While coprophagy is common in most hares, what is unique in L. brachyurus is that it reingests both soft and hard feces, as they are observed simply swallowing soft feces and chewing hard feces. Coprophagy is done to extract as many nutrients as possible from their difficult to digest plant food. There is also a positive relationship with the lack of available food and an increased occurrence of consuming hard feces. (Hirakawa, 1994)
- Plant Foods
- wood, bark, or stems
- Other Foods
Japanese hares are readily preyed on by red foxes (Vulpes vulpes), golden eagles (Aquila chrysaetos) and Japanese martens (Martes melampus). The color change in the northern subspecies of Japanese hares, from brown to white in the winter, is likely a cryptic color change to blend into their surrounding environment and avoid predation. (Enari and Sakamaki, 2012; Numone, et al., 2010; Shimano, et al., 2006)
- Anti-predator Adaptations
Due to the large population sizes of Japanese hares, they are extremely important in the food web. They are prey for larger mammals and they impact the vegetation on which they feed. They can cause damage to woody trees and plants when they are foraging for buds in the winter. (Enari and Sakamaki, 2012; Shimano, et al., 2006)
Economic Importance for Humans: Positive
Japanese hares are important economically to humans as a source of food and fur. (Angermann and Flux, 1990)
- Positive Impacts
- body parts are source of valuable material
Economic Importance for Humans: Negative
Japanese hares can cause damage to agricultural crops both by eating the crops and by trampling them. They are also considered to be pests because they damage the forest plantations which they inhabit. (Honda, et al., 2009; Torii and Suzuki, 1996)
Japanese hares are sources of and can transmit several diseases that affect humans. Tularemia, a bacterial disease caused by Francisella tularensis can be transmitted to humans by contact with L. brachyurus and if not treated quickly, can be lethal. Since 1960, approximately 1400 cases have been reported. Another disease, Q fever, which is caused by the transmission of bacterial Coxiella burnetii, induces fever-like symptoms and can later cause organ problems, can be transmitted from infected hares and other Japanese mammals. (Ejercito, et al., 1993; Park, et al., 2009)
- Negative Impacts
- injures humans
- crop pest
Japanese hares are considered least concern by the IUCN (2013). Although populations are considered stable, there have been suggestions on actions to maintain this stability. Saito and Koike (2009; 2013) stress the importance of forest regrowth and decreased deforestation to ensure there is no habitat loss for these hares. (IUCN, 2013; Saito and Koike, 2009; Saito and Koike, 2013)
Lepus brachyurus has been divided into two clades and four subspecies. The two clades are found in southern and northern Japan and appear to be the result of these groups evolving differently in these different regions approximately 1.24 million years ago. (Numone, et al., 2010)
Jennifer Holmberg (author), University of Manitoba, Jane Waterman (editor), University of Manitoba, Tanya Dewey (editor), University of Michigan-Ann Arbor.
uses sound to communicate
living in landscapes dominated by human agriculture.
- bilateral symmetry
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- causes disease in humans
an animal which directly causes disease in humans. For example, diseases caused by infection of filarial nematodes (elephantiasis and river blindness).
uses smells or other chemicals to communicate
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
an animal that mainly eats leaves.
A substance that provides both nutrients and energy to a living thing.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
An animal that eats mainly plants or parts of plants.
- island endemic
animals that live only on an island or set of islands.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
having the capacity to move from one place to another.
- native range
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
found in the oriental region of the world. In other words, India and southeast Asia.
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
having more than one female as a mate at one time
specialized for leaping or bounding locomotion; jumps or hops.
- scrub forest
scrub forests develop in areas that experience dry seasons.
- seasonal breeding
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
living in residential areas on the outskirts of large cities or towns.
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
- tropical savanna and grassland
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
- temperate grassland
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
living in cities and large towns, landscapes dominated by human structures and activity.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- young precocial
young are relatively well-developed when born
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Lumpkin, S., J. Seidensticker. 2011. Rabbits: The Animal Answer Guide. Baltimore, Maryland: The John Hopkins University Press.
Murray, D. 2003. Snowshow hare and other hares (Lepus americanus and Allies). Pp. 126-146 in G Feldhamer, B Thompson, J Chapman, eds. Wild Mammals of North America: Biology, Management and Conservation. Baltimore, Maryland: The John Hopkins University Press.
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