Category Archives: Wildlife

Interpretive Blogs about Wildlife and Plants

Opossum (Didelphis virginiana)

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Playing Possum….

You might have heard about ‘playing possum.’ Opossums will fake apparent death in order to escape a predator.

They are pretty convincing because the animal falls over and lies motionless for up to six hours! They also often release a very nauseating odor when threatened.

Opossum or possum….both bite. Photo courtesy of ODFW.

Opossums are not the only animal that will fake apparent death or tonic immobility. Evidently this technique is also used by fish, sharks, reptiles, rabbits, chickens, and ducks.

Description

The Virginia Opossum is a cat-sized gray and white animal with a pointed nose, beady eyes, and a naked scaly tail. This mammal will reach up to 40 inches long.

This nocturnal species has several adaptations that help make it successful, including:

  • Five toes and opposable thumbs on all feet make them agile climbers. Humans, gorillas, chimps, orangutans, gibbons also have opposable thumbs.
  • Extra keen eyesight–they have more than twice the number of rod-to-cone ratios compared to humans (50:1 vs. 20:1). Color recognition is limited.
  • They have very sensitive whiskers that assist their nocturnal movements.
  • The prehensile, rat-like tail is great for grasping plant materials and bedding material.    
  • Females have a pouch for holding newborns similar to a kangaroo. 

Origins

Opossums originated in South America. There are different theories about how opossums became established in the U.S. including migrations, as pets, for farming, and more.

What we do know is that this mammal is found in many parts of the U.S. and northwestern Canada. It is the only marsupial north of Mexico.

These mammals arrived in California and Oregon in the early 1920’s. Opossum were also farmed for their pelts and meat (considered a substitute for rabbit and chicken).

“I’ll be back and eat anything (almost).”
Photo royalty free, unsplash.

Diet

This opportunistic omnivore will eat almost anything. Much of their diet includes scavenged foods, like carrion. Other foods often include plant materials, insects, mammals, and reptiles, fish, amphibians, and more. 

Human activities have provided excellent opportunities for opossums by inadvertently providing shelter, food, and water. Recommendations for minimalizing problems include sealable waste containers, securing pet food and water inside at night, and cleaning up agricultural waste (such as dropped fruit).  

A Pest and Friend

Opossums are successful colonizers and survive in a wide variety of environments. They favor dark, secure areas and are active at night for potentially nine or more hours. Typical habitats include agricultural lands, forest communities, areas with small streams, and wherever humans are.

They are an invasive species in most places, but they do have a redeeming trait. Many large opossums are immune to rattlesnake venom and will regularly prey upon these snakes.

Fun Facts:

–The word “opossum” (borrowed from the Powhatan language) was first recorded by John Smith and William Strachey between 1607 and 1611.
–Opossums are finicky groomers.
–They can be trained to use a cat box.
–The species has a tendency towards cannibalism, particularly in over-crowded conditions.
–Juveniles swing from branches with their tails.
–It is illegal to keep this species as a pet (see State regulations).
–When threatened they will growl, hiss, strike, and attempt to bite. With approximately 50 teeth, it has the ability to hurt you and your pets.  If you have an infestation, call a professional.

REFERENCES:
–Oregon Dept. of Fish & Wildlife (https://myodfw.com/wildlife-viewing/species/virginia-opossum and https://myodfw.com/articles/furbearer-trapping-and-hunting)
–LafeberVet (https://lafeber.com/vet/basic-information-sheet-virginia-opossum/)
–Wikipedia, Apparent death and Opossum (https://en.wikipedia.org/wiki/Apparent_death and https://en.wikipedia.org/wiki/Opossum

Mountain Beaver (aka “Boomer”), (Aplodontia rufa)

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Test your knowledge with this ‘True or False’ quiz on Mountain beavers (answers follow):

  1. Fur trappers nearly wiped out Northwest boomer populations.
  2. Boomers are closely related to North American and Eurasian beavers.
  3. Boomers or “mountain beavers” are related to squirrels and will climb trees.
  4. Boomers must drink one-third of their body weight each day.
  5. All beavers fall trees, build dams, and live in lodges.
  6. Mountain beavers communicate via tail slaps, which is why they are called ‘Boomers.’
  7. The largest flea known lives exclusively on Mountain beavers.
  8. Boomers have unique teeth.  
  9. Boomers are asocial most of the time.
  10. These rodents live in deep burrows.
  11. Boomers have limited ability to see and hear.
Young Mountain beaver
(courtesy NPS and USGS)

Answers:

  1. False. Trappers nearly wiped out the American beaver populations, (not the Mountain beaver).
  2. False. Mountain beavers are not even in the same genus with real beavers (genus Castor). The Mountains do have several similarities in that they are relatively large rodents, smell bad, and have brownish-grey fur. This compact rodent weighs less than 2 pounds.
  3. True. Molecular results consistently identify a ‘sister’ relationship between the mountain beavers and the squirrel family (Sciuridae). Mountain beavers have large, curved front claws perfect for climbing, will climb nearly 15 feet up a tree to forage.
  4. True. These mammals are considered to be a living fossil with primitive, inefficient kidneys. They must drink a lot of water to survive. They live in watery/moist habitats up to the tree line in areas ranging from British Columbia south through to extreme western Nevada.
  5. False. Mountain beavers are strictly herbivorous and do not build dams or lodges, or have much of a tail to slap. Typically food includes ferns, salal, nettles, fireweed, bleeding heart, salmonberry, brambles, rhododendron, and young tree saplings.  
  6. False. Slap a less than 2-inch tail? Ouch. American beavers have a large flat tail that they slap to make noise.
  7. True. Hystrichopsylla schefferi is one of the oldest fleas in evolutionary history and females can be up to .5 inches long. Fortunately, the flea only likes Mountain beavers.
  8. True. Mountain beavers have unusual tooth projections and simple form. They are ever-growing.
  9. True. This rodent is not social…except to breed. They stick very close to their home burrow at all times.
  10. True. They create tunnel networks to store food, raise young, and avoid predators. Predators include cougars, owls, skunks, weasels, and domestic dogs. Tunnels can include ten or more exits.
  11. True. Limited sight and hearing is common for animals that spend a lot of time underground.

A few surprises?

Boomers, or “Mountain beavers”, would have a tough time living up to the merits of the well-loved American beaver.

These animals can become a nuisance

If they are a problem, contact the Oregon Dept. of Fish and Wildlife for regulations and relocation options.

REFERENCE:
–Oregon Dept. of Fish and Wildlife, beavers (https://myodfw.com/wildlife-viewing/species/beavers)
–Washington Dept. of Fish and Wildlife, Aplodontia-rufa (https://wdfw.wa.gov/species-habitats/species/aplodontia-rufa#living)
–Encylopedia Britannica, Mountain beaver (https://www.britannica.com/animal/mountain-beaver)
–USDI National Park Service, Mountain beaver (https://www.nps.gov/pore/learn/nature/mountain_beaver.htm)
–Wikipedia, hystrichopsylla schefferi and Mountain beaver (https://en.wikipedia.org/wiki/…)

Black-tailed & Mule Deer (Odocoileus hemionus)

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Photo courtesy of National Park Service

Black-tailed deer eat too much of my coastal garden

Healthy Black-tailed deer populations exist in western Oregon (and most likely my back yard). This ‘edge adapted’ species looks for forests with mixed age classes where it can hide in the dense forest cover during the day and eat everything in your garden in the morning or evening.  

Identification

Black-tails are a subspecies of mule deer which are found across the Pacific Northwest, from California north into Alaska. A large male (a “buck”) might stand three feet at the shoulder and weigh around 200 lbs.  An adult female (a “doe”) might weigh around 130 lbs.

Their tawny-brown coloring makes them difficult to spot. The wide, triangular tail with the white underside however is easy to spot as they gleefully bound into the forest after eating all of the flowers on the deck.

Adaptations

Deer communicate through touch, vision, sound, and scent which gives us humans some options for discouraging deer dining in our gardens. They are not as shy as one might think and have made themselves quite comfortable on our back deck, eating potted blueberries, petunias, and azaleas.

First off, they have excellent hearing and are not intimidated by barking humans. They know you are not a dog.

Domestic dogs are considered one of their predators. Other predators include coyotes, cougars, and humans.

Black-tailed buck, photo courtesy of National Park Service.

Male Blacktails have great vision and can spot other animals up to 2,000 feet away, even while chewing. The females do not seem to have that same capacity or are simply fascinated by a weird human running their direction and barking.

Black-tails are a popular game animal for hunters. Techniques used include: Spot and stalk, hunting blinds, still hunting, and rattling antlers. Scent control is very important when hunting these mammals.

Scent Deterrents

Scents can also help deter visitors. Deer naturally want to be able to smell their predators. Overwhelming smells can make that difficult to accomplish.

There are smell and taste deterrent sprays which help in the short term. Some strategies might also include hanging scented soaps, human hair, and diesel-soaked rags on or near affected plants. Many a neighbor has questioned why such things hang from our fruit trees and why the small stand seems to smell like a cheap boudoir certain times of the year.

Lastly, there are effective ways to deter damage. Check out the Manage Wildlife Conflicts in Your Home and Garden (https://catalog.extension.oregonstate.edu/pnw719/html) for ideas on blocking access and deterrence and Living with Nuisance Wildlife (https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/ec1579.pdf)

REFERENCES:
–Oregon Dept. of Fish and Wildlife (https://myodfw.com/big-game-hunting/species/black-tailed-deer and publications mentioned above)
–National Park Service, Olympic National Park ( https://www.nps.gov/olym/learn/nature/black-tail-deer.htm)