Opossums: More Friend Than Foe

By Anna Noble, Administrative Assistant

Virginia Opossum

Young Virginia Opossum
Photo by Kim Barker

California Wildlife Center admits an average of 250 opossums yearly.  Of this number, 40-50 are adults, while the remainder are orphans.  Most adult opossums who are admitted have experienced bodily injury due to trapping, predation, gun shots, or encounters with vehicles on roadways.  Joeys (the word for baby opossums) that are seven inches or longer should be left if found alone unless they show obvious sign of injury.  Smaller joeys should come to CWC for treatment.

While the opossum is sometimes perceived as a “nuisance” animal, they serve a pivotal role in the ecosystem.  Opossums act as nature’s double-duty pest control and sanitation.  They eat mice, rats, snakes, worms, slugs and insects, rotting fruits and vegetables, and even garbage.  As they have an unusually high need for calcium, they often eat the skeletons of rodents and road kill for a boost.

Opossums are incorrectly perceived as unclean and disease-ridden animals.  In fact, they bathe and groom themselves nearly as often as house cats.  They also have very powerful immune systems which fend off many diseases.  Opossums almost never have rabies, as their low body temperature makes it difficult for the virus to survive.  They are even immune to the venoms of snakes, scorpions and bees, as well as to ricin and botulinum toxin!  Despite having some similar physical traits, opossums are not related to rodents and are actually the only marsupial found in North America.

Despite their tendency to appear vicious when showing their fifty teeth, opossums are rarely looking for trouble.  They are very docile animals, and when threatened their first instinct is to simply run away.  If danger persists, they will show their teeth and make a hissing sound.  And when neither of these options prevail, they fall into a comatose state in which their bodies temporarily freeze, causing them to appear lifeless.  This defense mechanism is known as “playing possum.”

Coyotes Released

By Staff Veterinarian Dr. Lorraine Barbosa

Coyotes peer out of their transport crate while on their way to their release location. Photo by Aileen Martinez

Coyotes peer out of their transport crate while on their way to their release location. Photo by Aileen Martinez

This year, California Wildlife Center took in seven orphaned coyote pups, which came to us from various locations in Topanga, Los Angeles, and Hollywood, at only a few months old. After treating them for a GI parasites, giving them their vaccinations, and providing them with nutrition and supportive care, they spent several months rehabilitating in our outdoor coyote enclosure with minimal human contact. Our goal is for them to form a pack so that when they are released, they will be able to find a defend a territory together.

In the wild, coyotes are born into a pack led by a monogamous male-female pair.  Some youngsters will stay with their own packs while others will leave either to live on their own or in pairs, or to join another pack.  Coyotes defend their territories together but rarely hunt together unless they need to bring down large prey. The size of their territory is dependent on the on the size of the pack and the food sources available. Coyotes often use natural and man-made structures as territory boundaries, which is why you may see lone coyotes walking along roadsides – they are keeping to the edge of a pack’s territory.

When releasing our coyotes, we try to find a location that has the natural resources they’ll need to survive, including free space, prey, and a water source.  Without much human interaction over the past several months, these animals had grown very skittish of our presence, therefore, catching them up for transportation to their release location was a difficult task.

Peering in through the small opening of one enclosure, I could see only a jumble of ears, paws and noses protruding from a dense furred pile, each coyote looking away from me as if thinking, “if I can’t see you, you can’t see me.” With my Kevlar gloves on and a towel under my arm, I squatted down and began to crawl in, slowly and quietly, one small step at a time.  I knew that if I could cover their faces, they would calm and I would be able to work with them more easily.  While one coyote leaped repeatedly at a corner of the enclosure, another squeezed past me through the small enclosure door. I managed to cover two of the remaining coyotes with towels, keeping them quieted while Dr. Tom gathered the one that managed to sneak through, and then I wrestled with the coyote leaping at the enclosure corner.  Once all were covered and stilled, moving them the several feet from the enclosure into their kennels was a whole other task. It seemed simple enough, but coyotes have an unparalleled ability to enhance normal gravitational forces, pressing themselves so hard into the ground that one would think they weighed ten times what they do. It took all of my strength to move a 26-pound coyote one foot forward at a time toward and then into the kennel. One by one, with a great deal of coordination, composure and effort, we were eventually able to get all seven coyotes into their kennels, injury-free. We drove the short distance to our release site, walked the kennels down the trail a ways, then opened the doors and watched them run off up and over the hill and out of sight.


A Squirrel for All Seasons

Spring and fall are busiest times for baby squirrels
Eastern fox squirrels are one of the most common species of animals admitted to California Wildlife Center. CWC's Baby Care Unit also cares for large numbers of orphaned song-birds, opossums, hummingbirds, and crows.

Eastern fox squirrels are one of the most common species of animals admitted to California Wildlife Center. CWC’s Baby Care Unit also cares for large numbers of orphaned song-birds, opossums, hummingbirds, and crows.

By Executive Director Jennifer Brent

Last year, California Wildlife Center received 486 Eastern Fox Squirrels and so far this year, we have received 414.  They are the species that we see the most at CWC (second most common is the Mallard).

Why so many?  Some have had negative contacts with people – shot by a BB gun, struck by a vehicle or caught by a pet.  However, the vast majority we receive are babies (called kittens) and have fallen from trees of have otherwise been separated from their mothers. This may occur if a tree is trimmed during squirrel nesting season (February-April and August-October) or if the baby falls from a nest and it’s too dangerous for the mother to go down and retrieve him.

When baby squirrels are found on the ground, they should be observed from afar (as long as they are not in direct danger) to make sure that the mother picks him up.  If, after 3 hours, there are no signs of a mother coming, the squirrel can be picked up and put into a dark, quiet box with a small towel or blanket for warmth and brought to CWC.

Baby squirrels are fed a warmed species appropriate formula that mimics mother’s milk.  When very young, they are fed four times a day. Once they are old enough to be fed just three times a day, they are put together into social groups of four to seven squirrels who will act as surrogate siblings and eventually be released together.  A diet of nuts, berries and vegetables are introduced and, over time, this combination completely replaces the milk formula.  As with all rodents, squirrel’s front teeth grow continually so at CWC, they are given appropriate material such as pine cones and branches to keep them healthy.

Eventually the squirrels are self-feeding and are transferred from CWC’s Baby Care Unit to outdoor enclosures.  These allow them to move more freely and decreases any habituation that the squirrels developed while constantly being around people in the Baby Care Unit.  After about a month in the outdoor enclosures, they are released in their same social unit back into the wilderness. The average length of stay for a baby squirrel is three months at CWC.