Big Cypress Fox Squirrel
Sciurus niger avicennia
- The genus name Sciurus is from the Greek words skia (shadow)
and oura (tail), a reference to the bushy tail which casts a shadow
on the squirrel. The Latin species name niger (black) refers to
the black color phase which is common in this species.
- Fox squirrels may have earned their name from their gray and red fur
coat that resemble that of a gray fox, from their comparatively large size
and thick bushy tail, and/or from peculiar way of running along the ground
which gives the appearance of a small fox.
- Fox squirrels live from four to seven years of age on average in natural
conditions. One individual lived to 18 years of age in captivity.
- Ranges vary from 8-32 acres depending on habitat conditions. Fox squirrels
have large overlapping home ranges and are non-territorial.
- Fox squirrels are found throughout most of Florida except in the Keys.
There are three subspecies of fox squirrels in Florida. The Big Cypress
Fox Squirrel, Sciurus niger avicennia, is found from
the Caloosahatchee River in Lee county south and then east to the southern
part of Dade county. Sherman's Fox Squirrel, Sciurus niger shermani
is found throughout most of the peninsula. The Carolina Fox Squirrel
is found in the panhandle and northwards.
- Contrary to two common names sometimes given to the Big Cypress Fox
Squirrel -- Mangrove Fox Squirrel and Everglades Fox Squirrel -- it is
not common in either mangrove or Everglades habitats. It is most common
in open pinelands, live oak forests, and stands of bigger bald cypress.
- Fox squirrels are found throughout the eastern and central United States,
south into northern Mexico, and north into Canada. They have been introduced
into urban areas in western North America as well.
- Big Cypress Fox Squirrel: threatened species
- Sherman's Fox Squirrel: species of special concern
- Fox squirrels spend more time on the ground than gray squirrels and
are slower moving. They forage for acorns, nuts, fruits, insects, mushrooms,
buds and tubers, so they require habitats with an open understory. These
include open pine flatwoods, sandhills, mixed pine-hardwood areas and rangeland
interspersed with trees. In Florida, the fox squirrel may also be found
in cypress stands and occasionally mangrove swamps.
- Further north, fox squirrels are found in a diverse array of deciduous
and mixed forest. Areas with a good variety of tree species are preferred
due to variability in mast production.
- Fox squirrels weigh from one to three pounds, and exhibit color variations
which range from a buff color to gray, and in some instances black. The
under parts are usually lighter, and typical specimens have white noses
with black faces and feet. They are noted for their long, bushy tails
and for their strong hind legs which allows them to leap easily from place
- Fox squirrels have both
a summer and winter coat, and therefore molt twice each year. The spring
molt begins in March and may last for weeks, left, whereas the autumn
molt begins in September. But the tail only molts once each year during
- Fox squirrels have four sets of whiskers located above and below the
eyes, on the underside of the head in front of the throat, and on the nose.
Whiskers, also known as vibrissae, are touch receptors that provide
the animal with information about its immediate surroundings.
- Fox squirrels have very good eyesight even in dim light, and a wide
field of vision. They also have a well developed sense of smell and hearing.
- The skull of the fox squirrel has 20 teeth (gray squirrels have 22
teeth). Squirrels have upper and lower incisor teeth followed by a gap
called a diastema. The diastema is where the canine teeth would
normally be found in carnivorous animals such as cats or dogs, or omnivorous
animals such as monkeys. Behind the diastema are the cheek or grinding
teeth which consist of premolars and molars.
- As with other rodent species, the incisors continuously grow to compensate
for the enormous amount of wear that comes from a herbivorous diet.
- Young squirrels have milk teeth which are replaced by permanent teeth
when they are between six and twelve months old.
- Fox squirrels are highly adapted for climbing trees and fatal falls
are rare. Adaptations for climbing include sharp recurved claws, well developed
extensors of digits and flexors of forearms, and abdominal musculature.
- Tails are used for balance when running and leaping between trees,
and held over the back of a resting animal.
- Fox squirrels can mate any time of year, but they typically have two
breeding seasons. Males collect in the home range of a female when she
begins estrus. Dominance hierarchies form among the males to determine
mating privilege. Mating chases involve one female and a number of males,
with the successful male guarding the female to prevent others from mating
with her; males do not help in the raising of young. Copulation lasts less
than thirty seconds, and females can mate with several males. A copulatory
plug forms after mating.
- Females can produce two litters in a year, although one is the norm.
The winter litter is generally smaller than the summer litter.
- Functional testes descend in the scrotum from December to February
and May to July, although testes may stay descended without spermatogenesis
- Both sexes remain reproductively active throughout their lives.
- Sexual maturity : 10 to 11 months for males, 8 months for females
- Mating season: Fox squirrels usually have 2 breeding seasons
and litters a year. Breeding season peaks in January-February and again
- Gestation: 42-49 days The young are weaned in 2 months and on
their own in 3 months.
- Number of young: 3
to 4 young are born naked, blind, helpless, and weigh between 13-18g. Eyes
open at week 5. They remain in the nest 7 to 8 weeks.
- Dispersal of young: Juvenile males are more likely to leave
the natal area and disperse than are juvenile females. Dispersal usually
occurs during the fall and young males move between 1 and 16 kilometers
away from their natal nest. The longest recorded dispersal is 100 km. Dispersal
is a high cause of mortality among males, which results in a slightly female
biased sex ratio.
- Fox squirrels nest in cypress, cabbage palms, and pines.
- Fox squirrels typically use 3 different types of nests: winter dreys,
summer dreys, and dens.
- Dreys are round conspicuous twig and leaf nests built in trees between
25 and 45 cm in diameter. They are waterproof, and made of an outer layer
of interwoven twigs with a softer inner lining consisting of moss, bark,
leaves, fur, feathers, lichen or other similar material.
- Summer dreys are less elaborate than winter dreys and may be no more
than twig and leaf saucer shaped platforms on exposed branches. Dreys are
generally built in the upper 1/3 of the canopy and seldom in isolated trees,
which may serve to protect nests from predators.
- Tree dens are another type of nest used by fox squirrels. These are
holes or cavities in the main trunks of trees which are also lined with
soft material. Squirrels often use dens in winter months and dreys in summer
- Generally, fox squirrels are not gregarious, although they come together
during the breeding season when females are in estrus. Males have larger
home ranges than females.
- Squirrels threaten one another by an upright stance with their tail
over their back, followed by a quick flick of the tail.
- Scent-marking is another form of intra-specific communication used
by fox squirrels.
- Vocalizations in the form of barks and chatters, distress screams,
and high-pitched whines during mating are common. Fox squirrels are serially
- Fox squirrels are active year round during the daytime. Activity is
bimodal from late spring to autumn with peaks two hours after sunrise and
again from two to five hours before sunset.
- Squirrels mark their feeding territories with scents from glands on
the sides of their mouth that they rub against trees.
- Fox squirrels are generalist feeders and their diet is dependent upon
the area in which they are found.
- They forage on the ground and in trees, eating slash pine and cypress
seeds, cabbage palm fruit, acorns, and figs.
- They will also eat the inner
bark of trees as well as flowers, buds of some oak species, the fruits,
seeds, buds or flowers from a variety of trees including maples. Pine tree
seeds and pollen cones are readily eaten. Fungi are also consumed when
readily available in summer, as are cultivated crops in winter.
- Animal food items include bones, bird eggs, nestlings, gall insects,
moths, beetles, bird, eggs, frogs, and even dead fish.
- Fox squirrels are classic scatterhoarders (they cache seeds in a scattered
fashion). They carry nuts and seeds in their jaws and bury them in various
locations within their home ranges. Olfaction and memory are used in locating
their caches, but they only find a portion of the nuts they bury and are
important in planting many species of trees and shrubs that produce nuts
- Nuts are opened by a levering technique of the lowering incisors, a
skill at which squirrels become proficient quickly.
- Food consumption peaks in summer or autumn and decreases in winter.
Autumn rates of food consumption exceed energetic needs by 32% so that
the animals can increase their weight before the onset of winter.
- Owls, hawks, foxes, the coyote, and the bobcat are major predators
of the Fox Squirrel.
- When threatened or alarmed, the Fox Squirrel makes a barking call or
chatter while rapidly waving its tail from side to side. The Gray Squirrel
shows similar behavior, but its call is of higher pitch.
- Mange is the most common affliction affecting squirrels. More information