A neonatal squirrel's early behaviors are reflex reactions such as twitching,teat searching and yawning. First vocalizations are squeaks then later a more sophisticated repertoire develops. Similar to humans, a mother squirrel responds to babe's first words which are calls that are contact seeking, produced by hunger or distress. Other comfort behaviors develop are reflex scratching, resting and sleeping postures. Self grooming does not begin to develop until  @4-5 weeks ( eye  open)and not fully developed until 7-10 weeks (Gurnell, J 1987). Early development of behavior is geared to when the squirrel has graduated and is ready to move out of the nest.

Because tree squirrels are raised in nests high off the ground ,coordination and balance skills are honed.  An intense behavioral development period occurs when the eyes and ears open and the sense of smell has developed ( Gurnell) Squirrels at this time become more alert and responsive. Many of them get into trouble  when they wander out of the nest, not quite prepared. Sometimes we receive displaced infants who have injured themselves by falling from the nest .As the squirrels grow they may venture further out of the nest and eventually come and go at will. Similar to how we orchestrate a soft release! During this period they hone their skills of opening nuts and burying food .

J.P.Hailman writes of squirrel behavior: “ Just as the young squirrel must learn what is climbable and foraging during the dependency period may provide that experience. Beside the selection of food,other feeding behavior such as the opening of nuts, improves with time”.

Social behavior begins in the nest among family interactions between siblings and mother and is probably the most important factor in the development of behavior (Horwich, 1978) The young learn how to interact with each other through social grooming, and playing. Biting, chasing, mounting are practiced and refined. Rehabilitators can witness first hand the entertaining interactions of cage/littermates.

(Bakken, 1959) reports of young gray squirrels frolicking in-group play until 40 days after leaving the nest. The family may stay together or close for several weeks after the young first leave the nest but both mother and young lean toward increasing independence.

The next critical period is when the young squirrel attempts to establish residency within a community. Most will have their work cut out for them, as they are considered socially subordinate. Males have a larger home range than females. A home range is the place where squirrels live and carry out normal daily living routine.

Although gray squirrels tend to be individuals, they have adapted their own unique communication system using all the main senses: Sight, Smell, Sound and Touch.

 The nose knows. One way many tree squirrels communicate to other squirrels is by leaving their very own scent marks on branches. The sweat glands of a tree squirrel are located on their feet, between the foot pads and on their paws between their toes. Scent marks can sometimes strategically be placed on the underside of large branches so the rain won't wash away.Urine and other secretions darkly stain marking points that are used frequently. Gray squirrels also mark their territory by anal scooting or dragging. In rehab care you may notice that branches that are left in a cage over a season develop long dark stain marks.

The role of male urine as a form of olfactory communication is supported by the fact that at times of sexual activity the hairs on the scrotum of males become stained dark brown, probably by urine. These hairs are molted and replaced by clean white hairs (Taylor, 1968)

In a recent study  Belding's Ground Squirrels indicated that squirrels were able to recognize the degree of kinship by scent. (Mateo)

 Proper dining etiquette ? Not likely , but a form of behavior which involves wiping the upper and lower lips including the inner surfaces and cheeks against branches. One study suggests that squirrels mouth wipe at marking points (Taylor 1977). Squirrels traveling through the trees will stumble across these individual odors deposited by others and react to them. The sense of smell could reveal a squirrel’s social position or breeding condition. Urine and vaginal secretions of a female approaching estrus signal that she is ready to mate. This occurs indirectly from the scent marks and directly when the males sniff the ano-genital area of the female during the mating chase when love
is in the air !

Hello, can you hear me ? Most obvious when we observe and listen .Vocal communications serve a variety of functions and meaning.  Many of us are familiar with the warning call which is a series of rapid kwa-king sounds that warns of a predator .

Sometimes several squirrels can be seen high up on a branch looking down at a cat or dog, chattering away together accompanied by a brisk flicking of its tail. Females in heat will call her suitors with a duck-like "quacking," which can summon many eager males. Males respond with a buzz-like sound when chasing females.

Infant juveniles in rehabilitation often produce a purring sound when they are comforted with food or touch.

  The generic name sciurus is derived from the ancient Greek words skia meaning shadow and oura meaning tail. Thus translated as :a squirrel is an animal that sits in the shadow of its own tail. The tail has many useful functions, apart from being one of the most beautiful works of art ,it serves to balance when the squirrels jump and runs across branches and telephone lines! It functions as a personal thermo-regulator,shading the squirrel from the sun on hot sunny days and by wrapping the tail around its body on cold days. It also serves to insulate against the elements of snow, wind, rain. Skillfully flicked from side to side the squirrel uses its tail to distract a predator. When caught by a predator it serves as a unique defense mechanism and conveniently break off, allowing the squirrel a chance to escape. The exposed vertebrae usually dry up and fall off with no complications. If a squirrel is forced into water the tail can act as a rudder.

Like the ground squirrel, the gray squirrel has excellent muscular control over its tail, which can be twisted in any direction as well as elevating or depressing the long guard hairs. (MacClintock, D 1970) You may have seen this when a squirrel gets startled .

 A squirrel always wants to look his/her best ,apart from feeding and foraging. Older teenagers and adult gray squirrels in rehabilitation tend to urinate and defecate in one area. Infants and young juveniles possess no manners and tend to eliminate in no particular place. Urine may also be dropped along branches by breeding females and males as odor communication. The typical crouched position is on all four legs with the body held slightly over and parallel to the ground.

Keeping clean is a time consuming activity. Typical of many rodents ,grooming consists of a somewhat preset sequence of actions. This is described in detail by 2 studies (Laidler, 1980 and Horwich, 1972). The studies recognize 5 groups of grooming activities.

1.      Head and forepaw grooming.

2. Body grooming including hindlegs but not hindfeet

3.  Hindleg scratching

4. Hindfoot licking

5. Tail

The reported sequence: Sitting on its backlegs it starts licking the frontpaws and rubbing them down over its nose cleaning it. This can be repeated several times with the movement of the paws progressively taking in more of the face then the ears. After face washing the squirrel uses its mouth by licking and combing with the teeth cleaning the right and left side of its body, its hind legs, rump and finally saving the tail for last. Grooming the tail is from base to tip. Variations in the order sometimes occur.

Gray squirrels generally start to groom when eyes open.
The juvenile begins by separately washing different parts of its body such as tail, rump and hindlegs. Laidler (1980) suggests that face washing is the last technique to master. Eventually the actions are refined and combined into the characteristic sequence. (Gurnell)

  A type of grooming behavior, where close relationships between 2 or more squirrels is established, particularly litter or cage mates. In rehabilitation this behavior is observed between young cage mates. One study ( Horwich) describes social grooming between immature squirrels, which have been housed together for many weeks. It decribes one squirrel mouthing and biting the fur of another.

In my experience this behavior occurs between non-related cagemates as early as 6-7 weeks .

 Squirrels are extremely alert creatures and a common reaction that we observe is a squirrel assuming a freeze-like posture at any unusual sound or movement by remaining motionless. It blends in with the environment therefore making itself less noticeable to predators. If a squirrel sees a predator he also will give off an distress call. All squirrels make alarm calls which may warn others of approaching danger. Along with teeth chattering ,the tail may be fluffed and held up flicking back and forth.

An unusual theory:

"The squirrel making the call is risking its own life to the benefit of its relatives and close kin. "

According to Sherman (1977) on a  study of Belding’s Ground squirrels has shown that alarm calling is designed to favor ones relatives and thus influenced by kin selection. For example, adult females call more than males and females with close female relatives nearby call more than females with distant relatives nearby. The sex bias in calling could be related to the fact that males disburse further than females. Though risking its own life, the calling squirrel may save the lives of close relatives which share a high proportion of its genes.

This may be unique to this particular squirrel species .

One study  (Smith) suggests that the alarm call in fact is merely used as a distraction and warning to the predator .It is letting the predator know that he has been spotted and that all the members of the squirrel community know about it The squirrel is in fact in a relatively safe position with little risk to itself.

Running up a tree at lightening speed and flattening itself against a branch or tree trunk is another common behavior that squirrels exhibit when alarmed.

 No ,not squirrel football  ? Adult tree squirrels lead non-colonial lives. Beginning wildlife rehabilitators experience firsthand the unpredictable fickle nature of a gray squirrel raised from early infancy into pre-release age .The gentle infant that responded to your touch is now a hearty ,independent ,young adult, leaping from branch to branch away from you ( the predator)with lightening speed. Exceptions include habituated squirrels that are seen feeding close to each other without any aggressive actions, in urban and suburban park areas. Also in winter several squirrels may inhabit the same nest or den. In an effort to survive and to conserve energy and heat during the harsh winter gray squirrels will put up each other and bunker down together . I have seen this behavior several times at a local park and at local release sites where there were at least 2-6 squirrels sharing one den. Some studies suggest that huddling may be possible because the squirrels are close relatives, such as a mother nesting with her young of that year (Shorten, 1954)(farantinos, 1974) huddling behavior is not likely to happen in territorial pine and Douglas squirrels (Gurnell)

This basically refers to all the actions between 2 or more squirrels, which precede, involve, or follow a fight and includes aggressive, defensive, avoidance and escape behavior.

Gray squirrels are generally non-aggressive animals and tolerant. Squirrels would rather bluff their way out of a fistfight. Actual squirrel fights involve rolling or tumbling on the ground in close body contact. Head, shoulder back and ears are vulnerable injury area. During mating I have seen males with injured scrotums
actually punctured and bitten.

Typical body postures are associated with these acts. Threat posture a squirrels will crouch on all fours with its body slightly off the ground. The squirrel may rise up on its hindlegs from this position into an offensive threat or boxing position. Its fur is raised along the middle of its back and its neck is stretched forward toward its opponent (Gurnell) .Taylor (1966) reports a narrowing of the eye which is ringed by pale fur. Typical aggressive behavior is the focus of attention towards the opponent submissive squirrel on the other hand will crouch down with its tail relaxed, its neck bent slightly up, eyes wide open and ears held back against the head.

This posture seems to ward off the aggressor. Squirrels may attack without warning though not as likely. An attack usually ends up with one squirrel running away, being chased by the instigator.

It has been suggested that social rank is related to weight (Allen and Asprey, 1986). Dominant squirrels are generally heavier and bigger than submissive squirrrels. The relationship between squirrels becomes obvious when they congregate at a feeding station or when they mate. Established squirrels may act aggressively toward new immigrants. As the population changes and evolves so do the relationships shortage of a particular resource will act as a catalyst for dominant/submissive relationships. For example when food is the resource and there is a shortage, dominant squirrels will eat more, be healthier than submissive squirrels. There is the suggestion that some gray squirrels will defend stores of food close to nest trees (Nixon, 1984) or that some feeding areas will be defended (Kenward, 1985) It is not really known over what area dominance relationships are maintained. Further studies may be helpful.

Do not always occur at the same time in different studies. Reasons could include differences in field techniques and interpretation of data. Female gray squirrels act aggressive before the birth of their young and remain aggressive until after they are weaned (Bakken1959) This aggression is directed against other squirrels.

Mother squirrel becomes a sentinel, feverishly chasing away others that enter the” no fly zone”. Another time when agonistic behavior may peak is during mating seasons and when territories are first established. (Gurnell 1987) Despite defensive behavior squirrels spend little time on direct behavior with other squirrels and communicate with them from a distance using visual signs, scent marking and vocalizations .Squirrels busy day is spent doing “ squirrel things” such as watching out for predators, foraging, caching and eating food, grooming and resting.

The movement of animals out of an area (emigration) or into a population (immigration) is called dispersal. Young squirrels 6-12 months old tend to disperse more than adults do. (Jordan, 1971) The dispersal that occurs in the fall has been coined’the fall reshuffle”. Mortality rates for first year squirrels run as high as 75% (Woods) The timing of dispersal runs between august and mid-December (Flyger and gates, 1982) and mainly involves spring and summer born squirrrels. The degree of Dispersal appears to depend on food supplies especially seed trees. (Gurnell) If the nut crop fail to produce sufficient mast, hungry squirrels cannot find enough food to survive and thus move.

W.J.Hamilton Jr. gives this account: “A squirrel emigration of no mean proportion occurred in CT and NY during the fall of 1933.More than a thousand squirrels were observed swimming across the CT river between Hartford and Essex, a distance of about 40 miles. Many of them became exhausted and drowned while others climbed up on the logs, which they rested as they floated down the river. Still others came aboard ferryboats or scampered across bridges, which span the Hudson River, all moving in a westerly direction. Again during the fall of 1935 a similar and more extensive emigration extended into western N.Y.” ( Gurnell)

Reported by NYS Wildlife Pathologist Ward Stone

   " In the late summer and early fall in the Hudson River Valley area from Westchester to Warren county, much of the gray squirrel population underwent an emigration. WPU staff and volunteers began noticing an increase in the numbers of squirrels dead on the roadways around the end of august and into September. Calls from the public also indicated that something unusual was happening with gray squirrrels. One caller reported counting 900 squirrels crossing or dead on the NYS Thruway between Albany and Newburgh. Others reported seeing gray squirrels swimming across the Hudson River, the Tommanock reservoir and Saratoga lake. Gray squirrels were also seen moving at night, which is highly unusual-they see as well as humans in the dark and are vulnerable to predators. The last emigration in the Hudson River valley happened in the late summer-early autumn of 1968. 452 squirrels were collected and necropsied. Analysis of the data (at the time of the report) indicated that the majority of the squirrels (245 female and 207 male) totaling 90% were juvenile or sub-adult”

Food or water shortages brought on by drought or late frosts or overpopulation are theories behind mass emigrations.

One study suggests that dispersal is the main factor that regulates the size of a gray squirrel population and that is the result of food availability (Thompson, 1978)

Biological significance as noted by Richard G. Van Gelder “Dispersal by the young squirrels reduces the population in the parental environment thus contributing to a more or less stable home population.If the species population is at a low ebb the dispersing animals will repopulate the area or if the population is too high the dispersing animals are forced out into new areas where they become established,thus increasing the range of the species." “The great mortality that occurs during dispersal…reduces the pressure of predators on the parents and it introduces a strong natural selective pressure on the young dispersing animals”

There are many accounts of mass emigrations of gray squirrels. Seton estimates that nearly half a billion squirrels took part in the 1842 emigration that occurred in southeastern Wisconsin. Squirrel numbers declined as more forestland was cleared. During the 1800’s gray squirrels were quite unpopular. Many states offered bounties for their fur and the state of Ohio declared that county taxes could be paid in squirrel scalps values at 3 cents a piece. From 1900 to 1915 the numbers decreased so significantly that conservationists feared that the eastern gray squirrel may become extinct. Fortunately for the squirrel he has managed to once again adapt and survive.

 Dr John Gurnell ,a noted mammal expert,suggests that gray squirrels strongly influence the distribution and range of various oak species. Along with the bluejay, squirrels are crucial in regenerating second growth oak forests and may even have been responsible for spreading the vast stands of oak throughout North America after the last retreat of the glaciers 10,000 years ago.

Authors note : I would like to acknowledge the special group of people who recognize the value of studying , documenting and observing squirrel behavior both past and present; naturalists, biologists, scientists, field observers and  wildlife rehabilitator colleagues .And the squirrels ,who have passed along the lessons of animal medicine and walking in balance on our planet .

Barbara Bellens Picon
 ©2001
Revised 2002.

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