(DRAFT) - Taxonomy
Species RAT, KANGAROO, MORRO BAY
Species Id ESIS051002
Date 14 MAR 96
TAXONOMY
NAME - RAT, KANGAROO, MORRO BAY
OTHER COMMON NAMES - RAT, KANGAROO, MORRO BAY; RAT, KANGAROO and HEERMANN'S
ELEMENT CODE -
CATEGORY - Mammals
PHYLUM AND SUBPHYLUM - CHORDATA,
CLASS AND SUBCLASS - MAMMALIA,
ORDER AND SUBORDER - RODENTIA,
FAMILY AND SUBFAMILY - HETEROMYIDAE,
GENUS AND SUBGENUS - DIPODOMYS,
SPECIES AND SSP - HEERMANNI, MORROENSIS
SCIENTIFIC NAME - DIPODOMYS HEERMANNI MORROENSIS
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Morro Bay Kangaroo Rat
Dipodomys heermanni morroensis (Merriam, 1907)
KINGDOM: Animal GROUP: Mammal
PHYLUM: Chordata CLASS: Mammalia
ORDER: Rodentia FAMILY: Heteromyidae
Kangaroo rats are heteromyid rodents with large hind legs and
tiny forelegs, and a long tail. They are brownish above and white
below, and have a white stripe across the brown portion of the hind
leg (referred to as a "hip" stripe, but really a stripe across the
area between the knee and ankle). A small area around the bases of
the vibrissae is blackish, as are the upper and lower surfaces of the
tail. A white stripe runs the length of the tail on each side,
disappearing toward the tip, which usually has a tuft of longer hairs
at the end. External cheek pouches are present on each side of the
mouth, used for carrying food (04,05).
Heermann's kangaroo rat (Dipodomys heermanni Le Conte, 1853; one
of 21 species in the genus Dipodomys) includes 9 subspecies
representing regional variations within its distributional area in
central California. The Morro Bay kangaroo rat, D. h. morroensis, is
smaller (average adult weight: 65 grams; average adult total length:
Taxonomy - 1 (DRAFT) - Taxonomy
Species RAT, KANGAROO, MORRO BAY
Species Id ESIS051002
Date 14 MAR 96
293 mm) and darker than any other subspecies, and characteristically
lacks the hip stripe (92 percent of the specimens) seen of other D.
heermanni subspecies (01,04,09).
The Morro Bay kangaroo rat is sufficiently distinct to have been
considered a full species when it was first described (05). The name
has since been changed twice (01,04):
Perodipus morroensis Merriam, 1907 (05).
Dipodomys morroensis Grinnell, 1922 (04).
Dipodomys heermanni morroensis Boulware, 1943 (01,06).
Taxonomy - 2 (DRAFT) - Status
Species RAT, KANGAROO, MORRO BAY
Species Id ESIS051002
Date 14 MAR 96
STATUS
Coded Status
E: Federal Endangered
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The Morro Bay kangaroo rat (Dipodomys heermanni morroensis) has
been designated as Endangered pursuant to the Endangered
Species Act of 1973 (50 CFR 17.11; P.L. 93-205, 87 Stat. 884;
16 U.S.C. 1531-1540), as amended. The subspecies has this status
wherever found including the State of California. Critical Habitat
has been designated in San Luis Obispo County, CA including land,
water, and airspace (Mt. Diablo Meridian) of T 30 S, R 10 E, S 1/2
Sec. 14 and the portions of Sec. 23 and 24 west of Pecho Valley Road
(50 CFR, Sec. 17.95(a)).
This subspecies is protected by the Lacey Act (P.L. 97-79, as
amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import,
export, transport, sell, receive, acquire, or purchase any wild animal
(alive or dead including parts, products, eggs, or offspring):
(1) in interstate or foreign commerce if taken, possessed,
transported or sold in violation of any State law or
regulation; or
(2) if taken or possessed in violation of any U.S. law,
treaty, or regulation or in violation of Indian tribal law.
It is also unlawful to possess any wild animal (alive or dead
including parts, products, eggs, and offspring) within the U.S.
territorial or special maritime jurisdiction (as defined in
18 U.S.C. 7) that is taken, possessed, transported, or sold in
violation of any State law or regulation, foreign law, or Indian
tribal law.
RESPONSIBLE FEDERAL AGENCIES:
USFWS -Responsible for the management/recovery, listing, and
law enforcement/protection of this species.
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
STATE STATUSES AND LAWS:
STATE: California
Status - 1 (DRAFT) - Status
Species RAT, KANGAROO, MORRO BAY
Species Id ESIS051002
Date 14 MAR 96
DESIGNATED STATUS: Endangered
ADMINISTRATIVE AGENCY: California Department of Fish and Game
STATE STATUTE: California Endangered Species Act; Fish and Game
Code Chapter 1.5, Article 1, Section 2050.
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
The Morro Bay kangaroo rat (Dipodomys heermanni morroensis) is
listed as Endangered in the IUCN Red Data Book, 1971; and in the
Convention on Nature Protection and Wildlife Preservation in the
Western Hemisphere (1970).
ECONOMIC STATUSES:
This species has a value to naturalists.
70/08/25:35 FR 13519/13520 - Proposed rule
70/10/13:35 FR 16047/16048 - Listed as Endangered
76/08/30:41 FR 36517/36519 - Proposed determ. of Critical Habitat
77/08/11:42 FR 40685/40690 - Final rule, Design. of Critical Habitat
79/05/21:44 FR 29565/29577 - Five year review
85/07/22:50 FR 29901/29909 - Five year review
Status - 2 HABITAT ASSOCIATIONS
HABITAT - TERRESTRIAL
TERRESTRIAL
COASTAL
LAND USE -
Residential
Transportation, communications, and Util
Mixed Urban or Built-up Land
Cropland and Pasture
Mixed Rangeland
Sandy Areas other than Beaches
Transitional Areas
COMMENTS ON HABITAT ASSOCIATIONS -
Morro Bay kangaroo rats are essentially found only in
disturbed areas. Optimum habitat consists of the earlier successional
stages of the coastal sagebrush community which occur on the old,
stabilized dune terraces on the south and southeast sides of Morro
Bay. The optimum vegetation is essentially herbaceous annuals, with
scattered woody perennial shrubs (sagebrush - Artemisia californica,
coyote brush - Baccharis pilularis, lupine - Lupinus arboreus and L.
chamissonis, and buckwheat - Erigonum parvifolium) no more than 2 feet
in height. Shrub cover may be totally absent, or range as high as 60
percent; ground cover may vary from practically zero to 100 percent
(02,03,07,11,12,13,14).
Within the distribution area of Morro Bay kangaroo rats the above
habitat type is characteristic of early successional stages, until
from 15 to 30 years after an area has been cleared of vegetation,
depending on the specific site. Succession involves a gradual
increase in size and coverage of brushy species, and after 20 to 30
years the brush is too tall and dense for kangaroo rats. In earlier
times, vegetation was cleared and succession restarted as a result of
fires intentionally set by Indians; more recently brushy areas have
been cleared by bulldozers for either development or cultivation. The
animals quickly move into such areas, usually within the first year
after clearing. If the area is cultivated, they move in after the
first harvest of oats or other grain, or within the first year, if the
land is allowed to lie fallow (07,11,12,13,14). Large scale
development efforts and to a lesser extent cultivation (oats/pasture)
surround the known occupied habitat. Several roads surround the known
occupied habitat and provide access to homes, schools, and shopping
centers.
Soil is essentially raw wind-blown sand (but not active dunes),
anchored by the roots of the vegetation it supports. Burrows can
readily be dug in this soft substrate by the animals. Kangaroo rats
are not found on steeper slopes (over about 10 to 15 percent). They
have been taken from areas just above the highest tide level to an
elevation of about 1000 feet, but only in areas with sandy soil.
Burrows cannot be dug in the heavy clay soils found elsewhere in the
region (07,11,12).
Habitat Associations - 1 (DRAFT) - Food Habits
Species RAT, KANGAROO, MORRO BAY
Species Id ESIS051002
Date 14 MAR 96
FOOD HABITS
TROPHIC LEVEL -
HERBIVORE
LIFESTAGE FOOD FOOD PART
General Evergreen Shrubs-Flowers/Fruit/Seed
General Poaceae
General
General Forb Leaves/Stems
General Forb Flowers/Fruit/Seed
Food Habits - 1 (DRAFT) - Environment Associations
Species RAT, KANGAROO, MORRO BAY
Species Id ESIS051002
Date 14 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Terrestrial Features: Burrows
Environment Associations - 1 (DRAFT) - Life History
Species RAT, KANGAROO, MORRO BAY
Species Id ESIS051002
Date 14 MAR 96
LIFE HISTORY
FOOD HABITS:
Only Stewart has investigated food habits of Morro Bay kangaroo
rats; the following is taken from his report (11,12):
Plant species: Parts eaten: Acceptability:
California aster (Corethrogyne sp.) seeds high
deerweed (Lotus scoparius) seeds/leaves/stems high
western thistle (Cirsium occidentale) seeds high
cinquefoil (Potentilla lindleyi) seeds/pods/leaves high
cat's ear (Hypchoeris glabra) seeds high
filaree (Erodium cicutarium) seeds/leaves high
Cryptantha (Cryptantha clevelandei) seeds high
brome grass (Bromus sp.) seeds/leaves/stems high
sand verbena (Abronia sp.) seeds/pods high
turkish rugging (Chorizanthe californica) seeds high
black sage (Salvia mellifera) seeds high
mock heather (Ericameria ericoides) seeds high
woolly blue star (Eriastrum densifolium) seeds/pods high
Stephanomeria (Stephanomeria virgata) seeds high
Dudleya (Dudleya caespitosa) seeds/leaves/stems high
shrub lupine (Lupinus chamissonis) seeds/leaves/stems high
tree lupine (Lupinus arboreus) seeds/leaves/stems high
golden yarrow (Eriophyllum confertiflorum) seeds medium
sticky monkey flower (Diplacus aurantiacus) seeds medium
Croton (Croton californicus) seeds medium
dune buckwheat (Eriogonum parvifolium) seeds/flowers medium
tarweed (Hemizonia sp.) seeds medium
buckbrush (Ceanothus cuneatus) seeds/leaves low
Morro manzanita (Arctostaphylos morroensis) seeds/berries low
Also, captive individuals may eat snails and crickets (10), however,
there is no documentation to support this type of food consumption
in wild populations.
HOME RANGE/TERRITORY:
Each kangaroo rat adult maintains and defends its own burrow
system, which involves a main passage extending for 6 to 10 feet in
length, usually with 2 or 3 entrances. Home ranges may overlap,
although the animals are not truly social; only rarely are they
trapped more than 100 feet from their home burrow (02,08,09,11,12,14).
Population densities vary from 1 animal per acre to over 30 per
acre in optimum habitats (02,08,09,11,12,14).
PERIODICITY:
Morro Bay kangaroo rats are strictly nocturnal; they are active
early in the evening, and may or may not have another active period
before dawn (10,14).
MIGRATION PATTERNS:
The species is nonmigratory. Juveniles are occasionally taken in
Life History - 1 (DRAFT) - Life History
Species RAT, KANGAROO, MORRO BAY
Species Id ESIS051002
Date 14 MAR 96
unsuitable habitat, presumably as they are dispersing from their
natal burrow (10).
COVER/SHELTER REQUIREMENTS:
Morro Bay kangaroo rats require a relatively brush-free area
which supports a good growth of annual plants. What brush is present
should not exceed about 2 to 3 feet in height, or create any shaded
areas deficient in annual plants (07,11,14).
REPRODUCTIVE SITE REQUIREMENTS:
The kangaroo rats construct their own burrows, which usually
include 2 to 3 rooms, and numerous dead-end side pockets which are
often filled with seed caches (11,12).
REPRODUCTIVE CHARACTERISTICS:
Juvenile kangaroo rats have been captured in the field from March
to November, indicating at least two breeding periods per year,
possibly more. Probably only adults breed. Adult weight,
measurements, and pelage are achieved by the age of 19 to 20 weeks
(about 5 months). Females show evidence of estrous cycling about
every 15 to 20 days. Gestation in the related D. h. arenae is
approximately 30 to 33 days (09).
Litter size varies from 2 to 4 young.
PARENTAL CARE:
Young Morro Bay kangaroo rats remain with their mother in her
burrow until the age of about 5 to 6 weeks; captives are weaned at
about 4 weeks of age. Young are altricial, born without hair, pinkish
in color, and with eyes closed. The skin becomes pigmented and hair
begins to sprout within the first 2 weeks of development. Adult size
is reached at about 14 weeks (09,11), however, adult weight,
measurements, and pelage are achieved by the age of 19 to 20 weeks
(about 5 months).
POPULATION BIOLOGY:
The main limiting factor is the lack of suitable habitat within
the original range. The construction of housing has totally changed
some habitat, and fire suppression has allowed undeveloped areas to
mature into climax vegetation, which is to dense and tall for kangaroo
rats (07,09,10,11,12,13,14).
Current distribution is limited to one or a few isolated sites
still remaining in the area, with reduced populations which have
little or no contact with each other (09,10).
In 1977 a live-trap sampling method produced an estimate for the
total population of 1,200-1,500 individuals, conceivably as high as
2,000 individuals (08). In 1971 the population was estimated as 3,000
individuals while in 1957 it was thought to be about 8,000
individuals (02). Although sampling techniques differed on each
occasion this is believed to certainly reflect a real decrease in the
population (08,10). The 1977 study estimated a density varying from
42 per ha in optimal habitat to 5 per ha in marginal habitat (08).
SPECIES INTERRELATIONSHIPS:
Life History - 2 (DRAFT) - Life History
Species RAT, KANGAROO, MORRO BAY
Species Id ESIS051002
Date 14 MAR 96
Known predators of the Morro Bay kangaroo rat include:
gopher snake (Pituophis catenifer),
rattlesnake (Crotalus viridis),
barn owl (Tyto alba),
horned owl (Bubo virginianus),
gray fox (Urocyon cinereoargenteus),
long-tailed weasel (Mustela frenata),
badger (Taxidea taxus),
bobcat (Felis rufus), and the
domestic cat (Felis catus).
No direct causal relationships are known, other than that each of
these predators does take some kangaroo rats each year (10,11,12).
Stewart (11) reported that 88.5 percent of kangaroo rats he
examined had external parasites. Of these 73 percent had fleas, 37
percent had lice, and 35 percent had ticks. Unidentified nematodes
were found in the gut of one of five individuals (15).
OTHER LIFE HISTORY DESCRIPTORS:
Maximum longevity among captive D. h. arenae (a closely related
subspecies living in similar habitat) was about 7 years (10). Morro
Bay kangaroo rats probably live to only 2 or 3 years of age as is true
of many wild small rodent populations (15).
Life History - 3 (DRAFT) - Management Practices
Species RAT, KANGAROO, MORRO BAY
Species Id ESIS051002
Date 14 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Adverse Exotic/Feral/Introducted Species
Adverse Suppressing wildfire
Adverse Food Supply Reduction
Adverse Highway/Railroads
Adverse Hiking/Camping
Adverse Off Road Vehicles
Adverse Predation
Adverse Rural Residential/Industrial Areas
Adverse Transmission Lines/Towers
Adverse Vegetation Composition Changes
Beneficial Stocking captive-reared wild-strain animals
Beneficial Reforestation
Beneficial Restricting/regulating human use of habitats
Beneficial Maintaining Early Stages of Succession
Beneficial Controlling/Removing Native Vegetation
Beneficial Maintaining undisturbed/undeveloped areas
Beneficial Controlling/Restricting Off-Road Vehicles
Beneficial Land Acquisition
Beneficial Restricting/regulating human disturbance of populations
Beneficial Prescribed/controlled burning of habitat
Beneficial Transplanting wild animals
Existing Exotic/Feral/Introducted Species
Existing Suppressing wildfire
Existing Food Supply Reduction
Existing Highway/Railroads
Existing Hiking/Camping
Existing Off Road Vehicles
Existing Predation
Existing Rural Residential/Industrial Areas
Existing Transmission Lines/Towers
Existing Vegetation Composition Changes
COMMENTS ON MANAGEMENT PRACTICES -
The primary reason for the species Endangered status today is
the loss of habitat. The cause of habitat loss has been housing
development throughout much of the original range of the kangaroo rat,
particularly since about 1955. Homes, gardens, schools, shopping
centers, and other structures, plus the associated roads, parking
areas, and powerlines, have all replaced natural vegetation as the
human population of the area grew from 1500 (in 1958) to over 12,000
(in 1984). In addition, fire suppression has resulted in maturation
of the plant community and a reduction in food supply on still
undeveloped land, instead of maintaining the early successional stages
which are optimal for the kangaroo rats. Feral and pet cats
associated with the human population have more than replaced the
natural predators of the rats. Hiking, horseback riding and off-road
vehicle use have also contributed to habitat loss and burrow
destruction (02,03,07,08,09,10,11,12,13,14).
Management Practices - 1 (DRAFT) - Management Practices
Species RAT, KANGAROO, MORRO BAY
Species Id ESIS051002
Date 14 MAR 96
Future problems are also directly related to further human
population growth (10).
APPROVED PLAN:
U.S. Fish and Wildlife Service. 1982. Morro Bay Kangaroo Rat
Recovery Plan. U.S. Fish and Wildlife Service. Portland, OR. 69 pp.
The primary objective of the Morro Bay Kangaroo Rat Recovery Plan
is to preserve sufficient land and to maintain an optimum habitat for
at least 2,500 individuals. Attainment of this objective for three
consecutive years may permit reclassification to Threatened. Because
the population is very small and habitat is so limited, criteria for
declassifying have not been developed. The recovery activities
necessary to achieve the objective of declassification are:
1) To protect, secure, and enhance existing habitat through
existing laws and/or via acquisition, memoranda of
understanding or conservation agreements. Protection of
some areas (through management plans) from future development
will be necessary for both occupied and potential habitats.
2) To restore or create habitat of an early successional stage
through burning or mechanical brush removal or possibly using
selective, non-persistent herbicides with other treatments.
Development of management plans will be necessary in both
occupied and potential habitats. Restorative vegetation
manipulation may be necessary.
3) To monitor habitat conditions.
4) To determine environmental requirements, population dynamics,
and ecological/behavioral relationships.
5) To reestablish wild Morro Bay kangaroo rat populations with
captive bred stock and translocated wild Morro Bay kangaroo
rats.
6) Develop and implement public information and education
programs with displays, press releases, and presentations.
7) Enforce laws and regulations for protecting the Morro Bay
kangaroo rat. Controlling human access and ORV use may be
necessary.
Management Practices - 2 (DRAFT) - References
Species RAT, KANGAROO, MORRO BAY
Species Id ESIS051002
Date 14 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Boulware, J.T. 1943. Two new subspecies of kangaroo rats (genus
Dipodomys) from southern California. Univ. CA Publ. Zool., 46(7):
391-396.
02 Condon, J.D. 1971. Population estimate and distribution of the
Morro Bay kangaroo rat. Special Rept. for CA Dept. of Fish and
Game, WMB Adm. Rpt. 71-11 (mimeo).
03 Condon, J.D. 1975. Status of the Endangered Morro Bay kangaroo
rat. J. Mamm. 56:679-683.
04 Grinnell, Joseph. 1922. A gepgraphical study of the kangaroo rats
of California. Univ. CA Publ. Zool. 24:1-124.
05 Merriam, C.H. 1907. Descriptions of ten new kangaroo rats. Proc.
Biol. Soc. Wash., 20:75-79.
06 Hall, E.R. 1981. The mammals of North America. Second Edition.
2 vols., 1181 pp. and 90 plates.
07 Roest, Aryan, I. 1973. Morro Bay kangaroo rat habitat evaluation
study. Special report for CA Dept. of Fish and Game; W54R6-4.
25 pp. (mimeo).
08 Roest, Aryan, I. 1977. Distribution and population estimate of
the Morro Bay kangaroo rat. Special report for CA Dept. of Fish
and Game; S-1312. 19 pp. (mimeo).
09 Roest, Aryan, I. 1984. The Morro Bay kangaroo rat: A summary of
current knowledge. Poster session presented at; Am. Soc. Mamm.
Ann. Meeting, 24-28 June. Humboldt State University. 11 pp.
10 Roest, Aryan, I. 1985. Personal knowledge; recent observations.
Biological Sciences Department; California Polytechnic State
University; San Luis Obispo, CA 93407.
11 Stewart, Glenn. 1958. Notes on the Morro Bay kangaroo rat.
Undergraduate thesis. Calif. Poly. St. Univ. 449 pp.
12 Stewart, Glenn and Aryan Roest. 1960. Distribution and habits of
the kangaroo rats at Morro Bay. J. Mamm. 41(1):126-129.
13 Toyoshima, Janice. 1978. Small mammal monitoring study on the
Morro Bay Ecological Reserve. Special report for CA Dept. of Fish
and Game; S-1312. 18 pp. (mimeo).
14 Toyoshima, Janice. 1979. Current population and range of the
Morro Bay kangaroo rat. Report submitted to CA Dept. of Fish and
Game. 39 pp.
15 U.S. Fish and Wildlife Service. 1982. Morro Bay Kangaroo Rat
Recovery Plan. U.S. Fish and Wildlife Service. Portland, OR.
69 pp.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 Gambs, Roger. 1985. Pers. comm. Dr. Gambs has been conducting
a study of Morro Bay kangaroo rats in the field for the USFWS for
the past two years. He has submitted official reports to the USFWS
periodically.
02 Grinnell, Joseph. 1922. A gepgraphical study of the kangaroo rats
of California. Univ. CA Publ. Zool. 24:1-124.
References - 1 (DRAFT) - References
Species RAT, KANGAROO, MORRO BAY
Species Id ESIS051002
Date 14 MAR 96
03 U.S. Fish and Wildlife Service. 1982. Morro Bay Kangaroo Rat
Recovery Plan. U.S. Fish and Wildlife Service. Portland, OR.
69 pp.
04 Stewart, Glenn. 1958. Notes on the Morro Bay kangaroo rat.
Undergraduate thesis. Calif. Poly. St. Univ. 449 pp.
05 Stewart, Glenn and Aryan Roest. 1960. Distribution and habits of
the kangaroo rats at Morro Bay. J. Mamm., 41(1):126-129.
06 Toyoshima, Janice. 1979. Current population and range of the
Morro Bay kangaroo rat. Report submitted to CA Dept. of Fish and
Game. 39 pp.
References - 2