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Living OrganismsAnimalia / Craniata / Mammalia / Lagomorpha / Leporidae / Sylvilagus / Species

Sylvilagus bachmani - Brush rabbit (Click photographs/illustrations for full picture & further details)

Riparian brush rabbit. Click here for full page view with caption Young riparian brush rabbit. Click here for full page view with caption Brush rabbit Sylvilagus bachmani. Click here for full page view with caption Brush rabbit Sylvilagus bachmani. Click here for full page view with caption

INDEX - INFORMATION AVAILABLE

GENERAL & REFERENCES

APPEARANCE / MORPHOLOGY

LIFE STAGES / NATURAL DIET / PHYSIOLOGY

BEHAVIOUR

HABITAT & RANGE

CONSERVATION

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General and References

Alternative Names (Synonyms)

  • Sylvilagus macrorhinus. (B607.w20)
  • Sylvilagus riparius. (B607.w20)
  • Sylvilagus trowbridgii. (B607.w20)
  • Sylvilagus virgulti. (B607.w20)
  • Sylvilagus bachmani bachmani. (B430.w2, B605.5.w5, J469.34.w1)
  • Sylvilagus bachmani cerrosensis. (B605.5.w5, B607.w20, J469.34.w1)
  • Sylvilagus bachmani cinerascens. (B607.w20, J469.34.w1)
  • Sylvilagus bachmani exiguus. ( B607.w20, J469.34.w1)
  • Sylvilagus bachmani howelli. (B607.w20, J469.34.w1)
  • Sylvilagus bachmani mariposae. (B607.w20, J469.34.w1)
  • Sylvilagus bachmani macrorhinus. (B430.w2, B605.5.w5, J469.34.w1)
  • Sylvilagus bachmani peninsularis. (B607.w20, J469.34.w1)
  • Sylvilagus bachmani riparius. (B147, B605.5.w5, J469.34.w1)
  • Sylvilagus bachmani rosaphagus. (B607.w20, J469.34.w1)
  • Sylvilagus bachmani tehamae. (B607.w20, v)
  • Sylvilagus bachmani ubericolor. (B607.w20, J469.34.w1)
  • Sylvilagus bachmani virgulti. (B430.w2, B605.5.w5, J469.34.w1)
  • Lepus bachmani. (J469.34.w1)
  • Lepus trowbridgii (J469.34.w1)
  • Sylvilagus (Microlagus) bachmani (J469.34.w1)

Names for new-borns / juveniles

Names for males

Names for females

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General Appearance

Adult:

Specific Sylvilagus bachmani Information

  • This is a small species of cottontail with dark grey to brown fur and a paler grey underside. (B430.w2, B605.5.w5)
  • Medium-sized, with short hind legs, slender hind feet and medium-length ears. (J469.34.w1)
  • "All cottontails have relatively large ears and feet." (B605.5.w5)

Newborn: --

Similar Species

Specific Sylvilagus bachmani Information
  • The Brush rabbit is unlikely to be confused with other species of cottontails. (B430.w2)

Sexual Dimorphism

--

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References

Species Authors & Referees

Author: Kathryn Pintus BSc MSc MSc (V.w115); Dr Debra Bourne MA VetMB PhD MRCVS (V.w5)

ORGANISATIONS

ELECTRONIC LIBRARY
(Further Reading)
Click image for full contents list of ELECTRONIC LIBRARY

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Husbandry Information

Notes

  • --

Management Techniques

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Appearance / Morphology

Measurement & Weight

Notes

LENGTH
Adult:

Specific Sylvilagus bachmani Information

  • No significant sexual dimorphism. (B430.w2)
  • This is a small species of cottontail. (B430.w2)
  • Range: 303-369 mm. (B430.w2)
  • Average: 336 mm. (B430.w2)
  • Males: total length 303 - 356 mm, mean 332 mm. (J469.34.w1)
  • Females: total length 307 - 369 mm, mean 338 mm. (J469.34.w1)

Newborns: --

HEIGHT
Adults and sub-adults: --
Juveniles: --

WEIGHT
Adult:

Specific Sylvilagus bachmani Information

  • 511-917 g. (B430.w2)
  • Up to 1,000 g. (B605.5.w5)
  • Males: 511 - 797 g(J469.34.w1)
  • Females: 560 - 915g (J469.34.w1)

Newborns:

Specific Sylvilagus bachmani Information

  • Range: 24.3-30.2 g (terminal embryos). (B287)

GROWTH RATE:

Specific Sylvilagus bachmani Information

  • In Sylvilagus bachmani riparius held in large pens, weaning size about 96 - 103 g at about 14 -15 days. (B623.w1)

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Head and Neck

Notes

GENERAL HEAD STRUCTURE:
Adult:

Sylvilagus spp. General Information:
  • Ears
    • Medium-sized, approximately 5.5cm. (B285.w5c)
    • "The ears vary in size among the species but are generally of medium length for the Lagomorpha." (B147)
    • "All cottontails have relatively large ears." (B605.5.w5)

Specific Sylvilagus bachmani Information

  • Short ears. (B430.w2, B605.5.w5)
  • Medium-length ears, slightly pointed. (J469.34.w1)
    • Males: 45 - 63 mm (mean 57 mm). (J469.34.w1)
    • Females: 54 - 61 mm (mean 58 mm). (J469.34.w1)

Newborn: --

DENTITION:
Adult:

General Information

  • Rabbits and hares have a total of 28 teeth. (B285.w5a)
  • The lower tooth rows are closer together than the upper tooth rows. (B147)
  • Lagomorphs differ from rodents by having two pairs of upper incisors rather than just the one pair. The additional set of incisors are called peg teeth and are found directly behind the long pair in the upper jaw. (B147, B285.w5a, B605.1.w1)
  • At birth, lagomorphs actually have three pairs of upper incisors, but they quickly lose the outer incisor on each side. (B147)
  • The incisors are covered completely by enamel. (B147)
  • The upper incisors' roots are found in the skull's premaxillary bones. However, the length of the lower incisors' roots varies. (B147)
    • [Note: lagomorphs have teeth which grow throughout their lives. For this reason the portion of the teeth which is not exposed (not above the gum line) is strictly speaking not a "root"; however, it is sometimes convenient to describe it as a root.]
  • The first upper incisors have a straight cutting edge. (B147)
  • The peg teeth lack a cutting edge. (B147)

EYES:
Adult:

General Information

  • Lagomorph eyes are positioned such that they allow for good broad-field vision. (B285.w5a)
  • Hares and rabbits have large eyes which are adapted to both their crepuscular and nocturnal activity patterns. (B285.w5b)
  • Leporids have "large eyes to increase visual acuity in dim light." (B430.w2)

Newborn: --

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Legs, Spine and Tracks

Notes

Specific Sylvilagus bachmani Information
  • Short legs. (B430.w2, B605.5.w5)
  • Short hind legs and slender hind feet. (J469.34.w1)
  • Small feet. (B605.5.w5)
  • Feet are sparsely haired. (B605.5.w5, J469.34.w1)
  • Hind foot length:
    • Male: 71 - 86 mm, mean 79 mm. (J469.34.w1)
    • Female: 76 - 85 mm, mean 81 mm. (J469.34.w1)

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Tail

Notes

Specific Sylvilagus bachmani Information
  • Length: 10 - 30 mm (Average: 20 mm). (B430.w2)
  • Very small tail. (B430.w2, B605.5.w5)
  • Small tail, dorsally dark, ventrally white. (J469.34.w1)

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Skin / Coat / Pelage

Notes

Adult:

Specific Sylvilagus bachmani Information

  • The sides and back are usually dark grey, with the belly and underside of the tail being pale grey. (B430.w2)
  • The upperparts are dark brown to grey-brown, and the underside is whitish, including the underside of the tail. (B605.5.w5)
  • The feet are sparsely haired. (B605.5.w5)
  • Vibrissae mainly black, but the move ventral vibrissae may have white tips. The tail is dark dorsally, white ventrally. (J469.34.w1)

Sylvilagus spp. General Information:

Adult Colour variations: --

Newborn / Juvenile: --

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Detailed Anatomy Notes
(Summary information provided for pertinent species-specific data cross-referenced in Wildpro)

Notes

Skull

Sylvilagus spp. General Information:

  • Species of this genus have an interparietal bone. (B605.5.w5)
  • The skull has a highly fenestrated maxillary bone. (B605.5.w5)
Female reproductive tract

Specific Sylvilagus bachmani Information

  • Four pairs of mammary glands (one pectoral, two abdominal, one inguinal pair). (J469.34.w1)
Male reproductive tract

Lagomorph general information

  • Male lagomorphs lack a baculum. (B147)
  • Testes of lagomorphs are in the scrotum located in front of the penis. (B147)

Sylvilagus spp. General Information:

  • Males have inguinal and coagulating glands. (B287)

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Life Stages / Natural Diet / Physiology

Life Stages

Notes

BREEDING SEASON:

Specific Sylvilagus bachmani Information

  • Varies from north to south. (B605.5.w5)
  • California: December to May (B147, B430.w2, B605.5.w5, J469.34.w1), possibly to June. (B605.5.w5, J469.34.w1)
  • Oregon: February to August. (B147, B430.w2, B605.5.w5, J469.34.w1)
  • In the western USA, mating occurs between January and June. (B287)
  • In Sylvilagus bachmani riparius held in large pens (larger than the typical home range size), reproduction started in December and continued to October (versus the expected February to May); lactation continued into November. (B623.w1)

OESTRUS / OVULATION:

General Information

Specific Sylvilagus bachmani Information

  • Post-partum oestrus believed to occur. (J469.34.w1)
  • Synchronised breeding. (J469.34.w1)

GESTATION / PREGNANCY:

General Information

  • Under adverse conditions (such as during climatic or social stress), female lagomorphs are able to resorb embryos. (B285.w5a)
  • It is thought that some lagomorph species are able to conceive a second litter even before the last young is born; this is known as superfetation. (B285.w5a)

Specific Sylvilagus bachmani Information

  • Gestation period lasts between 24 and 30 days. (B285.w5c, B287)
  • Gestation period is approximately 27 days. (B147, B287)
  • Gestation 27 +/- 3 days. (J469.34.w1)
  • In California (USA), pregnant females have been reported between December and June. (B287)
  • In Oregon (USA), pregnant females have been reported between mid-February and mid-August. (B287)

PARTURITION / BIRTH:

General Information

  • Newborn rabbits are born with very little or no fur, and their eyes do not open until 4-10 days after birth. (B285.w5b)
  • Rabbits produce altricial kittens (B285.w5b, B430.w2) which are born into fur-lined nests built either under dense cover or within underground chambers. (B285.w5b)

Specific Sylvilagus bachmani Information

  • The young are altricial. (B430.w2)
  • In the western USA, young are both between January and May. (B287)
  • In Oregon, births are thought to occur in August. (B287)

NEONATAL / DEVELOPMENT:

General Information

  • Young are only suckled briefly once every 24 hours. (B285.w5b)
  • Rabbit kittens remain together within their breeding chambers. (B285.w5)

Specific Sylvilagus bachmani Information

  • The young are covered in fur when born. (B285.w5c)
    • Covered with thin fur at birth. (J469.34.w1)
  • The young are only fed at night. (B430.w2, J469.34.w1)
  • Eyes open at 10 days. (J469.34.w1)
  • The young will leave the nest within two weeks of being born. (B430.w2) after about two weeks. (J469.34.w1)
  • In a study in large pens (larger than the typical home range (0.33 ha) for the species) one young was caught in a trap when weighing just 70 g and with an estimated age of 10 days - younger than the 12 - 16 days at which it had been thought they left the nest. (B623.w1)

LITTER SIZE:

  • Females produce between two and six young per litter, generally three or four. (B287)
  • Litter size for this species varies between regions. (B605.5.w5)
  • Usually three young per litter. (B430.w2)
  • Average litter sizes:
    • Oregon: 2.87 young.
    • Northern and central California: 3.5 young.
    • West central California: 4.0 young.

    (J469.34.w1)

  • In a propagation pen, the average number of young per litter surviving to an age at which they were trapped was 2.9. (D377)

TIME BETWEEN LITTERS / LITTERS PER YEAR:

General Information

  • The inter-birth interval in lagomorphs is reduced by the phenomenon of induced ovulation, and post-partum oestrus, which allows females to conceive immediately after she has given birth. (B285.w5a)
  • A female can produce up to three or four litters per year. (B430.w2)

Specific Sylvilagus bachmani Information

  • Produces an average of five litters per year. (B285.w5c)
  • Usually produces three litters per year. (B147)
  • Three or four litters per year. (B430.w2)
  • Five to six litters per year. (B605.5.w5)
  • "The brush rabbit it one of the less fecund members of the genus." (B605.5.w5)
  • Interlitter interval is 29.5 days on average. (B287)
  • Females produce three or four litters each per year. (B287)
  • A female will usually produce about 15 young per year. (B605.5.w5)
  • In Oregon, average 5.29 litters per year. 
  • In California, usually three and sometimes four suggested. 
  • In Sylvilagus bachmani riparius held in large pens (larger than the typical home range size), females produced up to four litters per year. However, successful production of young was only 5.3 per female on average; only a third of females produced more than one or two litters per year. (B623.w1)

LACTATION / MILK PRODUCTION:

General Information

  • Leporids only release milk once in every 24 hour period. (B285.w5b)
  • Leporid milk has a very high fat and protein content, and as such is highly nutritious. Although the lactation period is brief, the milk is pumped into the young at a high speed.(B285.w5b)
  • The lactation period has a duration of between 17 and 23 days. (B285.w5b)

Specific Sylvilagus bachmani Information

  • The young are only fed at night. (B430.w2)
  • Young nurse for approximately two to three weeks. (B287)

SEXUAL MATURITY:

Specific Sylvilagus bachmani Information

  • At about four to five months; they do not appear to breed in the season of their birth. (J469.34.w1)
  • In Sylvilagus bachmani riparius held in large pens (larger than the typical home range size), reproductive maturity was reached at about 77 - 84 days of age at 550 - 600 g bodyweight; juvenile females unexpectedly reproduced and two of these females produced two litters in the year of their birth. (B623.w1, D377)

MALE SEASONAL VARIATION:

  • Sperm production occurs between October and July in California (USA), with a peak between January and May. (B287)

LONGEVITY / MORTALITY:

General Information

  • Rabbits and hares in the wild live for less than a year on average; a maximum age of 12 years has been recorded in a couple of species. (B285.w5b)

Sylvilagus bachmani specific information

  • In translocated Sylvilagus bachmani riparius, the major cause of death was known or presumed to be predation. Fatal diseases included Baylisascaris sp. infection, necrotizing typhlitis and intestinal lymphoma. One rabbit died due to its radiocollar. (B623.w1)

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Natural Diet

Notes

NATURAL DIET:

General Information

  • Lagomorphs only eat vegetation, mainly grasses and other herbaceous plants. Bark from young trees and small shrub stems may be eaten when food supplies are scarce. (B147, B285.w5c, B430.w2)

Sylvilagus spp. General Information:

  • Cottontails eat a wide variety of plants, the majority of which are herbaceous species. (B147, B285.w5c)
  • During the winter months in colder regions, cottontails feed on the bark and twigs of woody vegetation. (B147, B285.w5c)

Specific Sylvilagus bachmani Information

  • "Grasses are the most important element in a brush rabbit's diet." (B430.w2)

  • Edible grasses are the most important component of the diet. (J469.34.w1)

  • The majority of the diet is made up of grasses, but berries and other bits of vegetation are also eaten. (B605.5.w5)

  • Known foods include:

    • In September:

      • Creeping eragrostis (Eragrosis hypnoides). (B430.w2, J469.34.w1)

      • Spike rush (Eleocharis palustris). (B430.w2,J469.34.w1 )

    • In San Francisco valley:

      • Foxtail grass (Hordeum murinum). (B430.w2, J469.34.w1)

      • Soft chess grass (Bromis hordeaceus). (B430.w2, J469.34.w1)

      • Oats (Avena fatua). (B430.w2, J469.34.w1)

  • In winter, new grass when available, with Trifolium involucratum - Cloveri prefered when available. (J469.34.w1)

  • In summer also Rosa californica - wild rose, Sonchus asper - Sow thistle, Circium lanceolatum - Bull thiste, Chenopodium ambrosioides - Mexican tea, Baccaris douglasii and Juncus sp. - rush. In autumn, roots of Conium maculatum - Poison hemlock and both stems and leaves of Rubus vitiflis - Blackberry.  

  • This species also eats thistles and shrubs including blackberries (Rubus) and wild rose (Rosa). (B430.w2)

QUANTITY EATEN: --

STUDY METHODS: --

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Hibernation / Aestivation

Notes

  • Active year-round. (B147)

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Haematology / Biochemistry

Notes

HAEMATOLOGY: --

BIOCHEMISTRY: --

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Detailed Physiology Notes
(Summary information provided for pertinent species-specific data cross-referenced in WILDPro)

Notes

METABOLISM (TEMPERATURE): --

RESPIRATORY SYSTEM (RESPIRATION): --

CIRCULATORY SYSTEM (PULSE/HEART RATE): --

GASTROINTESTINAL SYSTEM (FAECES AND GUT MOTILITY):

  • Lagomorphs have digestive systems which are adapted for processing large quantities of vegetation. (B285.w5a)
  • Lagomorphs are well adapted for obtaining the greatest possible value from their food. They produce two types of fecal material: moist pellets and dry pellets. The moist pellets are expelled and then eaten (a behaviour known as coprophagy (B285.w5a)); this is done with little or no chewing, and as a result the majority of the food passes through the digestive tract twice (this is thought to have the same function as 'chewing the cud' in ruminants). The dry faecal pellets are not eaten. (B147)

URINARY SYSTEM (URINE): --

CHROMOSOMES:

  • 2n = 48. (J469.34.w1)
  • "This is the only species of Sylvilagus [Sylvilagus] known to have retained the putative ancestral karyotype (2n=48) shared by all known Lepus [Lepus], and by Romerolagus [Romerolagus]." (B607.w20)

MUSCULO-SKELETAL SYSTEM: --

SPECIAL SENSES AND VOCALISATIONS:

General Information

  • All lagomorphs use scent products secreted from special glands. (B285.w5a) These glands are located under the chins and in the groin, and are believed to play a key role in sexual communication, as well as in signalling social status in some gregarious species. (B285.w5b)
  • Whereas pikas tend to be more vocal, rabbits and hares rely strongly on scent rather than sound as a means of communication. (B285.w5b)
  • High-pitched distress squeals are emitted by leporids when captured by a predator, and specific alarm calls are produced in five rabbit species. (B285.w5b, B430.w2)
  • Some rabbit species thump the ground with their hind feet when faced with danger (B285.w5b, B430.w2); this reaction is thought to be a warning to nestlings underground. (B285.w5b)
  • The conspicuous white underside present on the tails of some rabbit species can act as a visual warning to other individuals when fleeing from a predator. These species tend to be found in more open habitats.(B285.w5b)

Specific Sylvilagus bachmani Information

  • Cries or squeals when frightened or in pain. (B430.w2)
  • Cries and squeals; squeals have been reported from young brush rabbits, and discress cries have been reported. (J469.34.w1)

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Behaviour

Feeding Behaviour

Notes

General Information
  • Lagomorphs are well adapted for obtaining the greatest possible value from their food. They produce two types of fecal material: moist pellets and dry pellets. The moist pellets are expelled and then eaten; this is done with little or no chewing, and as a result the majority of the food passes through the digestive tract twice (this is thought toe have the same function as 'chewing the cud' in ruminants). The dry faecal pellets are not eaten. (B147)

Specific Sylvilagus bachmani Information

  • Very cautious when emerging from dense cover to feed. (B605.5.w5)
  • Typically, brush rabbits will stay just inside brush before venturing into a close-by open area to feed and, having entered the open feeding area, they will stay motionless, appearing to watch for any signs indicating danger, before stating feeding. (B430.w2, J469.34.w1)
  • In some areas these rabbits remain in cover to feed (most of the time on the mainland), while in others (on Ano Nuevo island) they feed in the open. (J469.34.w1)
  • There may be several rabbits feeding in an area at one time. (J469.34.w1)
  • Gregarious when foraging. (B430.w2)
  • Newly-grown tips of plants are preferred: the rabbits will rise up on their hind legs to bute off a tip then use their teeth to draw it into their mouth. (J469.34.w1)

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Parental Behaviour

Notes

General Information

  • Male leporids are not generally involved in care of the young. However, if adult females attack young leporids, males will intervene, a behaviour known as 'policing'. (B285.w5b)
  • Even maternal care of the young is not particularly prominent in leporids, hence this reproductive strategy is known as 'absentee parentism'. (B285.w5a)
  • Leporids demonstrate an unusual system of nursing; the young are suckled only briefly (often less than five minutes) just once every 24 hours. (B285.w5b)
  • It is thought that the lack of social contact between the mother and her young is a strategy which diminishes the chances of attracting the attention of predators. (B285.w5b)
  • The entrances to breeding tunnels are carefully re-sealed following each bout of suckling (B285.w5b)

Sylvilagus spp. General Information:

  • The females of most species of Sylvilagus dig nest holes, about 100-150 mm deep and 120 mm wide; sometimes slanted, and both lined and covered with soft plant fibres and the female's own fur, which she plucks from her underside.  (B147)
  • The female does not herself live in the nest. To feed the young she crouches over the nest, the kits climbing to the top of the nest to nurse. (B147)

Specific Sylvilagus bachmani Information

  • The female produces a nest cavity about 75 x 150 mm, lined with fur and a little grass and covered with a plug (usually grass). The female feeds the young only at night. (J469.34.w1)

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Social Behaviour / Territoriality / Predation / Learning

Notes

SOCIAL BEHAVIOUR:

General Information

  • Most North American leporid species are solitary, but congregations of these animals often occur in favoured feeding grounds. (B430.w2)
  • Rabbits are solitary to gregarious. (B430.w2)

Sylvilagus spp. General Information:

  • Most species within this genus are solitary. (B147)
  • May chase off other individuals if they approach too closely. (B147)
  • "Not colonial, but some species form social hierarchies in breeding groups." (B285.w5c)
  • "Cottontail behavior is stereotyped and fairly consistent with other rabbit species." (B605.5.w5)
Specific Sylvilagus bachmani Information
  • "The behavior of the brush rabbit has not been quantified although some behavioral observations have been made." (B605.5.w5)
  • When frightened, this species will thump the ground with its hind foot for up to several minutes. (B430.w2)
  • This species is wary and secretive. (B430.w2)
  • Gregarious when foraging. (B430.w2)
  • These rabbits maintain a minimum individual distance which varies from 1 - 24 ft (0.3 - 7.32 m); closer approach results in a "chase", often with nose sniffing an touching preceding this. (B430.w2, B605.5.w5, J469.34.w1)
    • The lower limit of personal space (1 ft) was seen in juveniles. (J469.34.w1)
  • It has been noted that chases are often preceded by nose touching and sniffing. (B605.5.w5)
  • "In Oregon, the introduced eastern cottontail S.floridanus [Sylvilagus floridanus - Eastern cottontail] was reported to exhibit aggressive behavior toward the brush rabbit." (B605.5.w5)
PREDATION: 
Predator Avoidance

General Information

  • Rabbits use dense cover to hide from predators. (B285.w5b)

Sylvilagus spp. General Information:

  • When under threat from a predator, cottontails sit completely still and remain quiet, even when closely approached. They are capable of staying like this for 15 minutes if necessary. (B147)

Specific Sylvilagus bachmani Information

  • "Runways and tunnels afford escape paths through thickets." (B430.w2)
  • This species climbs into low trees or shrubs to avoid being caught by dogs and other terrestrial predators. (B430.w2, B605.5.w5)
POPULATION DENSITIES

Sylvilagus spp. General Information:

  • "Population levels vary markedly between species and from year to year, depending on climate, habitat type and other factors." (B605.5.w5)
  • Cottontails tend to be cyclic in abundance. (B605.5.w5)
  • "Habitat is the key to cottontail abundance." (B605.5.w5)
    • Desert species: normal densities are thought to be less than one rabbit per hectare. (B605.5.w5)
HOME RANGES AND DISTANCES TRAVELLED

Sylvilagus spp. General Information:

  • The home ranges of females are generally smaller than those of males. (B147)
  • These species have stable home ranges of a few hectares which overlap. (B285.w5c)

Specific Sylvilagus bachmani Information

  • This species has a small home range, usually less than 2,000 m2. (B605.5.w5)
  • The size of the home range will often depend upon the uniformity of the habitat. (B605.5.w5)
  • In Oregon, each rabbit tended to have a home range the size of the bramble clump it lived in; clumps less than about 460 mē were not lived in permanently. (J469.34.w1)
  • Larger home ranges for males than for females, and for juvenile than for adult males. (J469.34.w1)
TERRITORIALITY

General Information

  • Ranges of individuals may overlap in favoured feeding grounds. (B285.w5b)

Sylvilagus spp. General Information:

  • Not territorial. (B285.w5c)

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Sexual Behaviour

Notes

General Information
  • All lagomorphs use scent products secreted from special glands. (B285.w5a) These glands are located under the chins and in the groin, and are believed to play a key role in sexual communication, as well as in signalling social status in some gregarious species. (B285.w5b)

Sylvilagus spp. General Information:

  • "Several males may come together during the breeding season and pursue an estrous female." (B147)

Specific Sylvilagus bachmani Information

  • Sylvilagus bachmani - Brush rabbit in large pens were found (based on genetic analysis of offspring) to use a polygynous mating system; one male dominated mating but other males were also able to mate, based on genetic analysis. Promiscuity of females was confirmed because some females produced litters of young fathered by more than one male. (B623.w1, D377)

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Activity Patterns, Self-grooming and Navigation

Notes

ACTIVITY PATTERNS:

General Information

  • All the lagomorphs are terrestrial. (B147)

Sylvilagus spp. General Information:

  • Active year-round. (B147)
  • The majority of species move by characteristic bunny hopping. (B147)
  • It is thought that all species are capable of swimming. (B147)

Specific Sylvilagus bachmani Information

  • Captive individuals of this species has been observed ascending a short distance (1.2 - 1.5 m) into small Douglas fir trees to hide and rest. (B147, J469.34.w1)
  • This species climbs into low trees or shrubs to avoid being caught by dogs and other terrestrial predators. (B430.w2, B605.5.w5)
  • When pursued, the Brush rabbit tends to avoid open areas. (B430.w2, J469.34.w1)
  • It often lies in the sun in the morning, particularly following heavy rain or fog, also on sunny afternoons after morning rain. (B430.w2, J469.34.w1)
  • The hind legs are always moved together, the front legs also except when digging or moving forward very slowly. (J469.34.w1)
  • They will thump with the hind feet, sometimes for several minutes, after a fright. (J469.34.w1)
SELF-GROOMING:

Specific Sylvilagus bachmani Information

  • The brush rabbit exhibits stereotyped grooming behaviour. (B605.5.w5)
  • Following feeding, brush rabbits return to a form to groom, licking the head, body, hind feet then front feet. (J469.34.w1)
CIRCADIAN RHYTHM:

Sylvilagus spp. General Information:

  • Mostly nocturnal or crepuscular. (B147)
  • Cottontails are sometimes seen during daylight hours. (B147)
  • Active at night or during the day. (B285.w5c)
  • Mainly crepuscular, active sunset to 0200 then 0600 - 1030, and inactive particularly 1100 - 1600. (J469.34.w1)
SPEED OF MOVEMENT:
  • The North American leporids are able to escape predators by taking instant flight at high speed. (B430.w2)
NAVIGATION:

Specific Sylvilagus bachmani Information

  • Homing has been confirmed, but not from long distances (tested at 16 - 350 m). Sight appeared to be important, as they tended to home on clear nights. Individuals with larger home ranges showed between homing and homing time increased logarithmically with increased displacement distance. They kept to brush cover when available from release site to home range. (J469.34.w1)

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Habitat and Range

General Habitat Type

Notes

Specific Sylvilagus bachmani Information

Sylvilagus spp. General Information:

  • The presence of escape cover is an essential habitat requirement for these species. (B605.5.w5)

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Nests / Burrows / Shelters

Notes

Sylvilagus spp. General Information:

  • Cottontails are not thought to dig burrows. (B147)
  • Some species are known to make use of burrows made by other animals. (B147)
  • Also take shelter in brush piles and forms. (B147)
  • Several forms may be connected by flattened trails made through regular use of pathways. (B147)
  • "All species occupy burrows made by other animals or inhabit available shelter or hide in vegetation." (B285.w5c)
  • The females of most species of Sylvilagus dig nest holes, about 100 - 150 mm deep and 120 mm wide; sometimes slanted, and both lined and covered with soft plant fibres and the female's own fur, which she plucks from her underside.  (B147)
  • The female does not herself live in the nest. To feed the young she crouches over the nest, the kits climbing to the top of the nest to nurse. (B147)
Specific Sylvilagus bachmani Information
  • This species uses burrows, but does not make them itself. (B430.w2, B605.5.w5, J469.34.w1)
  • They use forms ("cleared places about the size of the rabbit") in the brush, with mazes of runways connectinv forms. (J469.34.w1)
  • "Runways and tunnels afford escape paths through thickets." (B430.w2)
  • The nest consists of a cavity measuring approximately 7.6 by 15.2 cm, and is lined with bits of dried grass and fur. The young are concealed within the nest by a "plug" of fur. (B430.w2)
  • The female produces a nest cavity about 75 x 150 mm, lined with fur and a little grass and covered with a plug (usually grass). (J469.34.w1)
  • This species makes use of extensive trail and runway networks within bramble clumps. (B605.5.w5)
  • They have been known to make use of wood rat Neotoma fuscipes macrotis (Muridae - Rats, mice, voles, gerbils etc. (Family)) huts, as well as using runways of Microtus and Reithrodontomys (Muridae - Rats, mice, voles, gerbils etc. (Family)). (J469.34.w1)

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Distribution and Movement (Migration etc.)

Notes

Specific Sylvilagus bachmani Information
  • Found on the western coast of the USA and Baja California. (B51)
  • This species is found from western Oregon to Baja California. Cascades to Sierra Nevada ranges. (B285.w5c)
  • The Brush rabbit is found in western Oregon, south of the Columbia River, down to Baja California in Mexico. Its distribution spreads eastwards to the Cascade-Sierra Nevada Range in the USA. (B607.w20)
  • Western Oregon to southern Baja California. (B147)
  • The distribution of this species is restricted to the Pacific Coast of North America. (B430.w2)
  • "It is found from the Columbia River in the north to the tip of Baja California in the south, from Pacific Ocean beaches east to the Cascade-Sierra Crest." (B430.w2)
  • This species is not found eastwards of the Cascade/Sierra Nevada Mountains. (B605.5.w5)
  • Found from sea level to elevations of approximately 2,070 m. (B430.w2)
  • The various subspecies are found in the following areas:
    • Sylvilagus bachmani bachmani - "...central California coast between the Salinas River and Morro." (B430.w2)
    • Sylvilagus bachmani cerrosensis - Found on Cedros Island, Baja California (Mexico). (B430.w2)
    • Sylvilagus bachmani cinerascens - "...southwestern California from about Bakersfield to extreme northern Baja California." (B430.w2)
    • Sylvilagus bachmani exiguus - "...central Baja California from El Crucero north to about San Vincente." (B430.w2)
    • Sylvilagus bachmani howelli - "...Baja California from about the California-Mexico border south along the Sierra de Juarez Mountains to about San Vincente." (B430.w2)
    • Sylvilagus bachmani macrorhinus - "...San Mateo and Santa Cruz counties, California." (B430.w2)
    • Sylvilagus bachmani mariposae - "...foothills of the Sierra Nevada Mountains in central California from about Sacramento to Bakersfield." (B430.w2)
    • Sylvilagus bachmani peninsularis - "...southern Baja California from El Crucero south." (B430.w2)
    • Sylvilagus bachmani riparius - "...known only from the type locality near Vernalis, Stanislaus County, California." (B430.w2)
    • Sylvilagus bachmani rosaphagus - "...Baja California along the coastal plain between about Ensenada and Rosario, Mexico." (B430.w2)
    • Sylvilagus bachmani tehamae - "...from north of Klamath Falls, Oregon southward along the east side of the coast range to about Sacramento, California, and from about Redding, California, south along the Sierra Nevada range to about Placerville." (B430.w2)
    • Sylvilagus bachmani ubericolor - "...western Oregon and California between the Columbia River in the north to San Francisco Bay in the south, and east to the summit of the Cascade Sierra Nevada Mountains." (B430.w2)
    • Sylvilagus bachmani virgulti - "...central California coast range between Berkeley and Mariposa." (B430.w2)

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Conservation

Species variation

Notes

Specific Sylvilagus bachmani Information
  • This species was formerly placed in the genus Microlagus. (B607.w20)
Currently recognised subspecies include:
  • Sylvilagus bachmani bachmani (B430.w2, B605.5.w5) including Sylvilagus bachmani macrorhinus, Sylvilagus bachmani riparius, Sylvilagus bachmani trowbridgii, Sylvilagus bachmani virgulti. (B607.w20)
  • Sylvilagus bachmani cerrosensis. (B605.5.w5, B607.w20)
  • Sylvilagus bachmani cinerascens: including Sylvilagus bachmani mariposae. (B607.w20)
  • Sylvilagus bachmani exiguus. (B607.w20)
  • Sylvilagus bachmani howelli: including Sylvilagus bachmani peninsularis; Sylvilagus bachmani rosaphagus. (B607.w20)
  • Sylvilagus bachmani ubericolor: including Sylvilagus bachmani tehamae. (B607.w20)

NB: names in non-bold font are reported as synonyms for that particular subspecies from the reference B607.w20.

Previously recognised subspecies include:
  • Sylvilagus bachmani riparius. (B147, B605.5.w5):
    • This subspecies is under threat of extinction. Its small range is found in the San Joaquin River Valley in California. A single population is thought to exist, numbering between 25 and 450 individuals, located within a park. (B147)
  • Sylvilagus bachmani macrorhinus. (B430.w2, B605.5.w5)
  • Sylvilagus bachmani virgulti. (B430.w2, B605.5.w5)

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Conservation Status

Notes

WILD POPULATION - IMPORTANCE:

Specific Sylvilagus bachmani Information

GENERAL LEGISLATION:

Specific Sylvilagus bachmani Information

  • U.S. Endangered Species Act (ESA) - Endangered. (NB: as Sylvilagus bachmani riparius). (B607.w20)

CITES LISTING: --

RED-DATA LIST STATUS:

Specific Sylvilagus bachmani Information

  • IUCN - Lower Risk (least concern). (W2.Apr08.w76)

THREATS:

Specific Sylvilagus bachmani Information

  • The subspecies Sylvilagus bachmani riparius is under threat of extinction from brush clearing and development of recreational facilities. (B147)
  • Adverse human activity and flooding may affect any potential additional range currently available for the endangered subspecies Sylvilagus bachmani riparius. (B147)

PEST STATUS / PEST POPULATIONS: --

CAPTIVE POPULATIONS: --

TRADE AND USE:

Specific Sylvilagus bachmani Information

  • This species is a game animal in California and Oregon. However, it is not frequently hunted. (B605.5.w5)

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