If you’ve ever seen a possum walking in tight circles or acting strangely, you may have wondered why they exhibit this unusual behavior. Well, you’re not alone! Many observe possums displaying repetitive, compulsive actions and want to get to the bottom of this peculiar phenomenon.
If you’re short on time, here’s a quick answer to your question: Possums tend to walk in circles due to a few possible reasons, including mating rituals, territorial markings, illness or parasitic infection, predator defense, or human-provided food sources.
In this comprehensive guide, we’ll explore the reasons behind the circling behavior in further detail, what it likely means, whether it’s normal, and how to respond if you see a possum spiraling near your home.
Mating Rituals and Territorial Markings
The Mating Dance
The mating ritual of the common brushtail possum is an intricate process that begins when males follow the scent trails left behind by females in heat. Once a male locates a receptive female, he initiates a mating “dance” by approaching her slowly while making rapid clicking noises with his tongue.
If the female is interested, she will allow the male to inspect her pouch. The male uses this opportunity to confirm the female is in estrus before mating commences.
This mating ritual serves an important biological purpose for possums. The inspection of the female’s pouch enables the male to detect if she has already mated and conceived joeys as he will be able to smell sperm and embryonic fluids present from previous matings.
This ensures the male does not waste time and energy pursuing a female who cannot produce offspring. Interestingly, female possums can foster embryo diapause which allows them to delay birthing one set of offspring while simultaneously mating with other males to produce another litter.
This complex reproductive strategy maximizes the female’s chances of reproductive success.
Scent Markings
In addition to the mating ritual dance, brushtail possums use scent secretions to mark their territories and signal reproductive status. Possums have a chest gland that produces a sticky, vanilla-scented substance males use to mark their territory boundaries while moving through treetops.
Males will also mark females with this scent during the mating process. The scent communicates vital information to other possums in the area regarding territory ownership and breeding opportunities.
Possums also have a cloacal scent gland used to mark dens, venues for mating, and territories. The scent from this gland tends to be strong and musky. Combiningchest gland secretions up high in trees along with cloacal scent markings down low provides a system of olfactory signals that facilitates breeding and reduces conflict over territory boundaries.
This combined use of urine and scent glands is why possums often appear to walk in circles near their dens and on the edges of their territories.
Illness or Parasitic Infection
Neurological Dysfunction
Possums walking in tight circles or rolling over on their backs can be signs of neurological issues caused by illness, injury, or even birth defects affecting the brain, inner ear, or nervous system coordination. Common causes include:
- Encephalitis: Inflammation of the brain often due to viral infections. It can impair balance, coordination and orientation.
- Stroke: Lack of blood flow in the brain leads to cell death and neurological dysfunction.
- Toxins: Lead poisoning, rat bait toxicity and other environmental toxins can damage nerves.
- Injury: Head trauma from an attack, being struck by a car or fall can damage parts of the brain that control movement and balance.
- Ear infection: Inner ear infection (otitis interna) interferes with the possum’s sense of equilibrium needed to walk properly without veering or circling.
In their weakened state, possums with neurological conditions also often fall victim to flystrike infections or predator attacks. Sadly, the prognoses for wild possums with severe neurological impairment are generally poor. Captive patients that receive supportive care have better survival odds.
Parasites
Certain internal or external parasites that infect possums can also manifest with circling behaviors. For example:
- Baylisascaris procyonis: Roundworms that migrate to the brain and cause severe neurological disease. Infected possums walk in repetitive circles.
- Toxoplasma gondii: A protozoal parasite carried by cats that causes toxoplasmosis infection leading to abnormal behaviors like aimless wandering in circles and head pressing due to brain inflammation.
- Mange mites: Burrowing mites trigger intense irritation, infections, and neurological issues from severely disrupted sleep that result in disorientation and repetitive motions.
- Ticks: Can transmit debilitating diseases like Lyme disease, Rocky Mountain spotted fever and tick paralysis that affect nerves, muscles and mobility.
With aggressive anti-parasitic drug treatment, some parasitic infections can be eliminated if caught early before permanent nerve damage sets in. However, certain parasites like Baylisascaris are extremely difficult to treat in advanced cases already showing neurological symptoms.
Predator Defense Strategy
Possums have developed some fascinating behaviors to help defend themselves against predators. Here’s an overview of some of their key survival strategies:
Playing Possum
The most famous possum defense mechanism is “playing possum”, also known as thanatosis. When threatened, possums will fall down, close their eyes, and enter a comatose-like state where their body goes limp, their breathing and heart rate slows down, and they release a foul-smelling fluid from their anal glands to appear dead.
This instinctive response can last anywhere from 40 minutes to 4 hours. Playing dead helps possums appear unappetizing and dissuades predators from continuing their attack. Researchers estimate that playing possum reduces a possum’s risk of predation by 50-70%!
Releasing a Noxious Odor
Along with playing dead, possums also emit a smelly green fluid from their anus when frightened. This putrid discharge comes from a pair of anal glands and can smell like rotten eggs or garlic. The terrible odor can sicken sensitive predators like dogs and foxes, making the possum less appealing as prey.
Baring Teeth
If playing possum doesn’t work, possums will switch to “plan B” and bare their teeth at the predator. They often hiss or growl too. This bluffing strategy makes them appear vicious and dangerous. It’s mostly for show since their 50 sharp teeth are better adapted for chewing plants, not flesh.
Circular Walking
When nervous or disoriented, possums will sometimes walk in tight circles. Researchers think this may relate to the possum’s poor eyesight and inability to find escape routes. The circling may also disorient predators and limit their ability to attack from behind.
Aggression
Contrary to their docile nature, possums can become very aggressive when they feel extremely threatened. As a last resort, they will bite, scratch, screech, and strike predators with their claws. But this is rare since playing dead is their primary line of defense.
Food-Conditioned Behavior
One of the main reasons why possums and other urban wildlife may walk in circles or exhibit other odd behaviors is because they have become food-conditioned. This means they have learned to associate humans and man-made structures with easily accessible food sources.
As a result, their natural behaviors and survival instincts have become altered.
For example, possums that regularly scavenge human trash and food scraps left outside may begin to linger around houses and neighborhoods more often. They quickly realize these areas provide a consistent buffet of leftover pet food, unsecured garbage cans, and crumbs or compost that get tossed in yards.
This reliable access to calories causes the animals to spend less time wandering and foraging in wooded areas as they naturally would.
Additionally, wildlife rehabilitators note that food-conditioned animals seem to lose their fear and wariness of humans over time. A possum that grows dependent on raiding leftovers from a certain property may feel comfortable enough to den and sleep under nearby sheds, decks, or porches during the daytime.
This leads to very visible daytime activity as the animals grow accommodated to human routines and surroundings.
Disorientation and Circling
The unnatural foods wildlife consume from human sources may also physically affect them by upsetting digestive systems adapted for wild, raw foods. Things like processed sugars, dairy, wheat-based foods, seasonings, and other human food ingredients can cause gut inflammation, metabolism disruption, and nutritional imbalances in animals not meant to consume such things.
This in turn may negatively impact their cognition, spatial awareness, balance, and eyesight. Possums and raccoons that have been documented walking repetitive circles or falling over repeatedly often test positive for things like pancreatitis, metabolic bone disease, or toxicity from ingesting toxins found in trash.
The neurological and physiological effects from poor diet seem to manifest in awkward motor control and disorientation.
Behavioral Changes
On another level, some biologists theorize that the ready calories provided by humans fundamental alters social dynamics and behaviors among urban wildlife communities. Groups may become dependent on a single den location situated near a guaranteed food source rather than ranging more widely.
This can change population densities and create localized overcrowding.
Young animals also spend less time learning essential skills like identifying naturally occurring foods, hunting live prey, avoiding predators, and finding suitable shelter locations if they can simply sit near a dumpster to eat.
They grow up to perpetuate odd behaviors, since their mother may have displayed the same food-conditioned conduct.
Ultimately, the unnatural surplus of calories wildlife access from careless human waste and feeding seems to enable a cycle of accelerated reproduction and survival unlikely to be sustained if urban food sources disappeared.
This may underlie some of the visible impacts to wildlife behavior when dependent on inappropriate food-conditioning.
When to Be Concerned
Possums walking in circles can sometimes be a sign of neurological issues that require veterinary attention. Here are some guidelines on when you should be concerned about this behavior:
Persistence of Circles
If your possum continues to walk in tight circles for more than a day or two, it’s time to call the vet. Transient circling that resolves on its own is not too worrisome. But neurological issues tend to cause consistent, repetitive circling motions.
Other Neurological Signs
Along with the circling, watch for other potential indicators of neurological problems like balance issues, head tilt, weakness, or seizures. The presence of multiple neurological symptoms warrants a veterinary exam to pinpoint the cause.
Injuries or Trauma
Sometimes a head injury or trauma can cause temporary circling motions. If your possum recently had an accident or injury preceding the circling, it’s a good idea to get it checked out. There could be concussion, fracture or other issues needing treatment.
Older Age
Elderly possums are more prone to age-related cognitive decline that can manifest as circling behavior. If your older pet suddenly starts displaying repetitive circles, veterinary guidance is advised.
Appetite and Activity Level
Significant changes in appetite, energy level, or normal behaviors accompanying the circling are clues something more serious may be brewing. Subdued activity and disinterest in food are particularly concerning.
Conclusion
In summary, possums displaying circular walking patterns could be exhibiting mating dances, territorial markings, illness, predator defense, or food-seeking behavior. While the reasons behind the circling vary, it’s most often completely normal possum activity.
If the animal seems unhealthy, confused, or the spiraling persists for days, it may need medical care. Otherwise, enjoy the rare glimpse into the unique rituals of the misunderstood possum! Their circling habits are a window into the species’ behavioral biology we’re still unraveling.
