Face-to face with an opossum

T-R PHOTO BY GARRY BRANDENBURG - An opossum (Didelphis virginiana) gives us a face-to-face view this week. Long guard hairs on its muzzle work as sensory detectors as the critter searches for any and all types of foods to eat. The average size can be 21 to 36 inches long, including the prehensile tail. Weight will be between 4 to 15 pounds. A thick while fur covers the entire body of this cat-sized animal. It has black eyes, black ears, pink nose, pink feet and pink tail. There are 50 teeth within its jaws. Life span is two to four years. They are intelligent. They are survivors. And they are North America's only marsupial mammal.

OPOSSUMS are common, consistent and an enduring member of North America’s native wildlife. This animal was first noted and described by settlers along a young America’s east coast as people arrived from Europe. This mammal, our only marsupial, has managed to spread its population across many portions of the United States. It also lives in Central America. They are adaptable to living in close association with people in both rural and urban settings. Part of the reason for their survival hinges on a diet that excludes nothing. If an opossum finds a small living creature such as ground nesting birds, their eggs, snakes, insects, frogs, plant parts in gardens or forest floor, fruits, grains or dead animals, it will be consumed. In urban settings, cat and dog food dishes left outside will be perfect targets for night-time raids.

Opossums have little body fat. They do not hibernate. So even in the winter, they have to go looking for food at least every other day because they are hungry. A den site can be a hollow log, an abandoned coyote, fox or badger den. The sleeping area of the den will have a collection of dry grasses and leaves accumulated during the prior fall season. These nest linings help create a bit more insulation from cold air.

Young newborn opossums have a unique task immediately after they come into world. They must crawl along the mother opossum’s belly fur to reach the entrance to this marsupials pouch. The fur-lined internal pouch provides warmth and places for the young to suckle mom’s milk. It takes about 12 days from breeding time for the bumblebee-sized young to be born. They are far from fully developed. It is inside the mother’s pouch that continued growth takes place during the next 60 to 70 days. At that time young opossums will take brief outside exploration journeys. They may still prefer to crawl back into mom’s warm pouch. At 80 to 90 days of age, they are getting too large for the litter of up to 10 to fit inside the marsupial pouch home they were familiar with. Now they will grasp the fur of the mother and take rides on her back as mom waddles around the forest, grassland or city backyards searching for food.

Opossums have enemies to avoid. The list is long as just about all ground or avian predators will take the opportunity to eat opossums. Coyotes, foxes, dogs, raccoons, bobcats, owls, eagles and hawks will be watching. And road crossings have their own hazards as vehicles speed along a roadway. One tactic opossums use to avoid predators is to play dead, or as we humans like to call it, play opossum. An opossum that is being attacked may lay down, pretend it is dead, open its saliva fomenting mouth while exposing its teeth and tongue. And to add lots of distasteful elements to animal trying to bite it, a foul-smelling fluid is secreted from its anal glands. Once a predator decides to leave the dead opossum alone, in a few moments time, the animal will ‘wake up’ to resume normal activities. It should be noted that while an opossum is playing dead, it is fully alert to its situation. It just wants the predator to be tricked into leaving it alone.

Opossum’s are survivors. They are not dumb. Mother Nature has carved out a place for this species of animal. If you should see an opossum during an outdoor hike, bike ride or foray into a forest, stop an admire this survivor from ages past, who even today is making it quite clear that all it wants to do is live and survive. Our only marsupial species of North America does very well, thank you.

Our IOWA RIVER source is Crystal Lake in Hancock County has a new problem. ZEBRA MUSSEL juveniles have been found there during routine examination of sampling devices monitored by DNR staff. At this time no adult zebra mussels were found, so continued monitoring will be sure to follow this summer. Zebra mussels are an invasive species. Biologist do not want them. But wanting to not have them and dealing with them if they once get established are two different things. It is a pest and a big time disrupting agent in aquatic ecosystems.

Zebra mussels may have been inadvertently transported by boat or boat trailer from nearby Clear Lake. Clear Lake has an infestation of zebra mussels. The little D shaped shell has alternating dark and light bands on its shell. Most adult zebra mussels are one half to one inch long. They will form dense clusters attaching to any hard substrate. They can form enough mass to block intake pipes if an urban water supply come from the lake. Young zebra mussels are microscopic so it is not surprising that contaminated water held inside boat trailer frames, boat live wells, bilges, ballast tanks or bait buckets can inadvertently spread the pest. There is no effective treatment for a lake once they have infested its waters.

Boaters and anglers are urged to be diligent with their gear, boat and boat trailers. Drain all water holding compartments after leaving a lake or any water body. Then allow time for the drained equipment to dry completely before refilling or relaunching of a boat into a different lake. Clean off any aquatic plant debris that may cling to a boat or boat trailer. Power wash a boat hull with hot water. Or better yet, allow boats and trailers to dry for at least five days before reusing. And never release plants, fish or animals into a new body of water after contact in other water bodies.

A list of aquatic invasive species and a list of infested waters in Iowa can be found in the 2019 Iowa Fishing Regulations booklet. Or you can do a of research at the DNR website www.iowadnr.gov/ais. A personal contact may also be made to Scott Grummer at 641-357-3517 or Kim Bogenschutz at the Boone Wildlife Research Station at 515-290-0540.

JULY 4th is coming up quickly. Many folks with time off from work and using July 5 as a vacation day can make a four-day weekend getaway. For lots of people it will be camping time, fishing time, cooking over an outdoor grill time or boating on a lake perhaps pulling water skiers. If boating is what you have in mind, be safe, be alert at all times, have designated boat operators, and have life jackets worn by all passengers all the time. Avoid water hazards such as floating logs or debris from recent flooding events. Know before you go. You can truly only have fun by avoiding mistakes while in or on the water.

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Garry Brandenburg is a graduate of Iowa State University with BS degree in Fish & Wildlife Biology. He is the retired director of the Marshall County Conservation Board. Contact him at PO Box 96, Albion, IA 50005.