Bones

I always experience a little burst of excitement when I find a skeleton.  This may be a carryover from my Elementary School days when I had visions of becoming a paleontologist, or it could be from my Junior High period of reading everything I could about adventurous archaeologists/treasure hunters searching for amazing discoveries.  In the books, treasure usually wasn’t far behind the discovery of a skeleton.  I found this wonderful specimen in the midst of a cedar thicket.

Many times you can identify the species, or at least the genus, from the shape of the skull.  Opossum was the first animal that came to mind when I saw the shape of this skull.

The size however, indicated a much smaller animal.  This is only about half the size of a typical Opossum skull.

The skull holds the key to identification in the form of a dental record.  Using the pattern of dentition, the range of possible animals can be narrowed considerably.  Step one is to determine the total number of teeth.  Here we have a total of 20 teeth in the upper jaw.

A check of the lower jaw shows 10 teeth on one side, so doubling that gives us a total of 20 lower teeth.  That tells us to suspect mammals with 40 total teeth.

There is only one native Ohio mammal with a total tooth count of 40.  That is the Raccoon.  The trouble is that this doesn’t look like the skull of a Raccoon.  Total tooth count helps narrow your search, but to fine tune or verify a choice, you need to look at the dental formula.  That formula takes the total number of teeth and breaks it down into the number of incisors, canines, premolars and molars in the upper or lower jaws.  One side of this upper jaw appears to have five incisors in front of the long canines.

A closer examination confirms that fact.  The jaw clearly contains five incisors on each side.  Raccoons only have three incisors per side, so this is clearly not a Raccoon.  Browsing through the dental formulae reveals only one mammal with five incisors to a side and that is the Opossum.  So, why the small size and only 40 teeth?

This is apparently the skeleton of an immature Opossum.  A close examination of the lower jaw reveals undeveloped teeth that have not yet emerged.  Many mammals do not get their full complement of teeth until maturity.  Had this little fellow survived a few more months, it would have acquired all 50 teeth characteristic of the species.  Proper identification of most living things requires consideration of many details.  Don’t be eager to make an identification based on just a single point.

Opossum

I’ve been noticing a lot of fresh digging in the yard and fields, so I decided to set one of the live traps and see what has been foraging during the nighttime hours.  It was no surprise to have the first capture be a Opossum.  Opossums are quick to enter a baited trap and after making a meal of the bait, settle down to await the door to be opened.  If you set your trap in the same location several nights in a row, the Opossums will sometimes make the trap a regular stop in their foraging pattern.

The bald patches around the eyes identified this individual as one I have been seeing regularly in the evenings.  Opossums have 50 teeth, more than any other Ohio mammal.  Add some hisses and a low growl and this animal can put on quite a threatening display.  It seldom bites, but I would rather not be the recipient of one of those rare attacks.

There are five toes on each foot and each toe, except the inside toe of the hind foot, has a well developed claw.  The claws are super tools for digging up grubs, worms and any other tasty morsels.  They also aid in climbing.

The tail is definitely rat-like with its scaly, naked appearance.  The tip of the tail appears to have been lost.  Damage to ears and tails from freezing temperatures is common.  Considering the many nights of subzero temperatures we experienced this winter, I’m surprised that this guy isn’t showing more damage.

One of my reasons for capturing these animals is to see what they are carrying in the way of an external parasite load.  Ticks find the Opossum quite attractive and I often find dozens of ticks around the ears and neck.  We usually have active ticks as soon as the temperature hits 70 degrees and we’ve had several days of temperatures in that range.  So far this year, I’ve seen no ticks and the Opossum seemed tick free.  I hope that’s a sign that it’s going to be a light tick year.

When caught in the open, a Opossum usually becomes immobile and waits for danger to go away.  If it appears safe to do so, the Opossum will begin to move slowly away.  Often it will rock forwards and backwards as if mimicking a small shrub being blown by the wind.  I had to back off about 40 feet before this guy began to move.

Once they reach some cover they pick up the pace.

After going about 60 feet through the tall grass, the Opossum broke into the open and raced along the tire tracks left by the electric contractors who installed new wire and poles last fall.  At the intersection of the old fence line, the Opossum took a quick turn and disappeared into a brush pile.  I imagine I’ll probably see him in the yard again this evening.

Winter Opossum

When temperatures dip well below freezing, nocturnal animals that are susceptible to the cold will often venture out in search of food during the slightly warmer daytimes hours.  Opossums are common foragers around the bird feeding area, but are rarely seen during the day.

When I saw this guy making his way through the field beside the house, I knew where he was headed.  I hurried around and met him as he arrived at the feeder.

Opossums normally don’t react to my presence if I move slowly and don’t crowd.  They act as though I’m just another animal taking advantage of the food supply.  The ears and tails are susceptible to frostbite during cold weather and always look a bit ragged on the older specimens.

If I do get too close to the Opossum and it decides to leave, it will begin its escape with an exaggerated slow motion walk.  I guess I’m not supposed to notice that it is moving.

It’s unusual to find an adult Opossum that looks sleek and clean.  This one has notches in its ears, a ripped place on its side and a scabby, mangled tail.  It may be different in the southern portion of their range, but I don’t think our cold winters do them much favor.

Once they feel they’ve gotten away from me, they move on with more haste.  I doubt that they are capable of outrunning any legitimate predator.  It’s fortunate that they have excellent reproductive success and introduce many new Opossums into the population each year.

A Camera Critters submission.

Faux Snake

There are many wild animals living in my barn and I’ve learned to recognize the sounds made by most of them. Occasionally, one will fool me. When I heard a slow, steady movement through a straw pile, along with the soft scrape of scales against chicken wire, I was sure it was the sound of a hunting black snake. What I discovered was the strangest snake I’ve ever encountered.

Tracking down to the other end, I found a decidedly unsnake-like head.

My activity had awakened a sleeping opossum and he was trying his best to do a slow slink away from me.

Once discovered, opossums generally sit quietly and stare at you. They are masters of the slow sneak and will make their retreat in super slow motion. When they believe they’ve left the threat behind, they’ll shift into running opossum mode.

Like just about every other wild mammal at Blue Jay Barrens, the opossum carries a load of ticks. May seems to be a peak time for ticks and the mid sized mammals always carry a heavy load of the parasites. I sometimes wonder how such a small animal can stand to lose so much blood.

NOTE: Sorry about the late posting yesterday. Blogger was having difficulties and was not accessible for about 20 hours. The problem also resulted in the loss of many comments posted during the last two days.