Lepus brachyurus

Geographic Range

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.

• Biogeographic Regions
• oriental oriental
  • native native

• Other Geographic Terms
• island endemic island endemic

Habitat

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.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland
• forest forest
• scrub forest scrub forest

• Other Habitat Features
• urban urban
• suburban suburban
• agricultural agricultural

Physical Description

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.

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.

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.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike
• female larger

Reproduction

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.

• Mating System
• polygynous polygynous
• polygynandrous (promiscuous) polygynandrous (promiscuous)

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.

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.

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.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous
• post-partum estrous

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.

• Parental Investment
• precocial precocial
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female

Lifespan/Longevity

Japanese hares do not live longer than 4 years in the wild.

Behavior

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.

• Key Behaviors
• terricolous
• saltatorial saltatorial
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• solitary solitary

Home Range

The home ranges of Japanese hares are 10 to 30 hectares in size.

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.

• Communication Channels
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

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.

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.

• Primary Diet
• herbivore herbivore
  • folivore folivore

• Plant Foods
• leaves
• wood, bark, or stems

• Other Foods
• dung

Predation

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.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

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.

Economic Importance for Humans: Positive

Japanese hares are important economically to humans as a source of food and fur.

• Positive Impacts
• food food
• 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.

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.

• Negative Impacts
• injures humans
  • causes disease in humans causes disease in humans
• crop pest

Conservation Status

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.

Other Comments

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.

Additional Links

Encyclopedia of Life

Contributors

Jennifer Holmberg (author), University of Manitoba, Jane Waterman (editor), University of Manitoba, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

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