by Carl Strang
I like our native marsupial, as the length and content of this week’s species dossier may reveal.
Common in DuPage County, IL, and around Culver, IN. Usually found around trees, though it more often uses burrows (dug by other animals) as daytime rest sites in DuPage. Strictly nocturnal most of year, but comes out for occasional daytime wanderings, especially in late winter. Has a prehensile tail. Female has pouch in which small young reside; older ones ride on her back. Highly variable in most physical characteristics, including facial appearance, color (black, white and gray offspring once in a single litter brought to Willowbrook). Breeding season varies, too; young babies with mother May-August. Climbs trees frequently. Tracks 5 toes front and back, usually walks in trot gait, with front foot’s toes spread widely, giving impression of a star. Hind foot of same side placed sideways, large thumb pointing inward, remaining 4 toes out, and placed against back of front foot so as to appear to be partly wrapped around it. Dead ones are so common along the road that auto accidents may be the major cause of death in DuPage. Opossums usually don’t snap or bite. They give an open-mouthed, hissing threat. Are the over-sized but weakly anchored canines more for bluffing than eating? Usually they can be carried by the tail, but this is not recommended because some will climb up and try to bite. I haven’t seen the “playing possum;” when this behavior is reported to Willowbrook, it’s usually in the context of the animal being bitten by a dog. The skull is characterized by a large cranial ridge and tiny brain cavity.
25JA86. Willowbrook. Heavy raccoon and opossum activity after snow fell but before a large, sharp drop in temperature.
18FE86. Tracks indicated much opossum (also skunk, raccoon) activity on a relatively warm night after a week of extreme cold and an ice storm.
10NO86. Young opossum making a nest in its aquarium at Willowbrook. Tore off pieces of newspaper from floor with mouth and carried them in tightly curled tail into folded towel, further shredding and incorporating them into previously gathered material. After initial tear, pushed paper with front feet underneath him, transferring or pushing it into partly curved tail with hind feet. Tail gripped paper. Hind feet appeared to grasp the material, even small pieces, and stretched the feet backwards to stuff them into the growing bundle.
11JA87. Waterfall Glen, in 6 inches of snow that fell 2 days before. No raccoon signs, but several opossums had been out (all from burrows in ground). One followed in young woods between railroad tracks and Des Plaines River, east of Sawmill Creek. It dug a hole and defecated skins and seeds of American bittersweet or something very similar at base of large tree. Went into and out of a second burrow distant from the first. Frequently and I believe nonrandomly brushed against large trees. Straddle wide (7.5 inches). Dug in 2 other places; couldn’t tell if it ate anything. Entire counterclockwise circular path ~300m long.
20JA87. No sign of opossums in the 3 nights since 4 inches of snow.
14MR87. Meacham Grove. Medium-sized opossum tracks on long, roundabout path through woods and on out of preserve. I picked up another, same size (same animal?), followed it to hollow-log den. Frequently turned to the side and dug shallowly in litter. Three times its path crossed similar thick (1/2-3/4″ diameter, ~2″ long segments) droppings med-dark brown with fibrous matrix and much seed content, looking like millet from bird feeder. I don’t think these were deposited by this animal on this trip, though. No frequent contact with trees, though the second animal seemed to prefer to walk along tops of fallen logs and sticks rather than walk on ground (1/2″ new icy snow on ground). Holes in litter mostly distinct from those dug by squirrels by being less focused, shallow scrapings. Typically wider than long, as opposed to squirrels’ longer than wide, and without nut-hole in bottom. Possibly a more circular, displacement of litter rather than the squirrels’ linear digging. I backtracked the original animal’s winding route until it went off the preserve on its north edge (entire ramble encompassed ~1/3 of the small western part of Meacham Grove). It dug out an old rabbit skin, fur still on, but apparently didn’t find anything edible left.
10DE87. One set fresh opossum tracks in Willowbrook’s Back 40, compared to lots of raccoon sets.
23DE87. In recent nights much opossum activity, some raccoon activity.
20JA88. Lots of raccoon and opossum activity last 2 warm nights, Willowbrook. Stream high, no crossings observed.
1JE88. An adult opossum out and quietly moving about at this hot noontime hour (>85 degrees F).
9MR89. Despite increased warmth over past 2 nights, no use of trails by opossums or raccoons.
9DE89. McDowell Forest Preserve. Half-grown opossum, foraging mid-morning. Nose very active, ate several small fruits among fallen leaves. Hackberries. It was unwary; I could approach closely. When walking it tends to trot, especially when it speeds up. 4 separate footfalls when slower, but they are departures from a diagonal walk or trot sequence rather than a pace. Later (11:30am) I saw him, or another of same size, go into a burrow about 1/4 mile away from the first site.
14JA90. Most of a roll of photos taken in the dried bed of McKee Marsh, of an opossum eating a dead fish, ~10:30am.
22JA90. Willowbrook. Lots of opossum activity above pond. One followed some distance: mostly a steady walk, centers of track-pairs 1 hand-span (8″) apart, and in a straight line. When a curving turn made, tracks became very close together; more erratic in appearance. Altered route slightly to get around sticks, tufts of grass, etc., that could have been stepped over with a little effort.
12FE06. McDowell Grove. I picked up an opossum trail in the snow, the animal having come up from the West Branch. Snow had fallen before its walk, and then during the opossum’s wanderings, as the tracks had less and less snow in them and ultimately none at all. It occasionally dug in leaf litter, was interested especially in areas around fallen logs and at the bases of large trees. Den in a rotted out cavity in the base of a standing tree, near the trail junction where a former bit of landscaping was done in the northern part of the preserve. Den entrance photographed.
24FE07. A large opossum walking through woods at Blackwell, far from any feeders, at 9a.m.