Apr 1, 2009

Virginia Opossum

They are “living fossils,” having survived relatively unchanged for at least 70 million years when dinosaurs also roamed the planet.  They are the only living marsupials in North America.  The first known usage of their name occurred in 1610 literature for Jamestown, Virginia.  “There are…Apossouns, in shape like pigges.”  The word opossum comes from the Algonquian Indian language meaning “white animal.”


Opossums are solitary nocturnal animals that are as common in the suburbs as they are in rural areas.  About the size of a housecat, they have a naked prehensile (grasping) tail, naked ears and opposable “thumbs” on their rear feet.  When they hiss or growl, they show their 50 sharp teeth.  No other land mammal has so many teeth.  They have very poor eyesight but a keen sense of hearing to help avoid predators, and an even keener sense of smell to aid in finding food.


They seem to eat anything.  Favorite foods include insects, snails, rodents, eggs, snakes, frogs, crayfish, fruit, berries, and carrion.  While foraging for food they travel an erratic path, changing directions every few steps and constantly poking at objects on the ground, testing everything as a possible food source.


Opossums are prolific breeders.  Mating season extends from January to July, with 2 litters produced annually.  After a gestation period of only about 12 days, more than a dozen honeybee-sized young are produced.  The blind embryo-like babies immediately crawl unaided into the mother’s abdominal pouch where they attach themselves to one of her 13 nipples.  Those that do not find a nipple soon perish.  Shortly after a baby begins to nurse, the nipple swells and completely fills its mouth so tightly that the baby becomes firmly attached to the mother. It will stay attached for the next 2 months.  As they grow and can no longer fit in the pouch, they will then clutch the mother’s fur and ride on her back as she hunts for food.  The young are independent and on their own at 3 to 4 months.


An injured or threatened opossum will pretend it is dead or “play possum.”  It will go into a near coma and its breathing will become almost undetectable.  It lies on its side with mouth and eyes partially open, tongue hanging out, and often emits a greenish fluid from its anus with an odor that is putrid to most predators.  When danger passes it will get up and meander away.


Opossums have a relatively short lifespan, especially for their size and metabolic rate.  Their average lifespan in the wild is only about 2 years.  They are preyed on by many species of animals, including coyotes, foxes, large hawks and owls.  As scavengers, they frequently hunt along highways for garbage and road kill where they frequently fall victim to that ultimate predator, the automobile.


Contact Gayle at her website for nest boxes at www.woodlandhabitat.com or gaylepille@yahoo.com


The Spring Peepers are a Peepin'

They are tree frogs, but are usually found at ground level.  Their “peep” is deafening and sounds like sleigh bells - only louder.  In the northeast they are referred to as “pinkletinks” or “tinkletoes.”  To us though, they’re simply called Spring Peepers, and the Peepers are out in force.


Spring Peepers are the most widely distributed chorus frogs in Kentucky.  They are also one of our smallest frogs, about the size of a nickel.  Like all tree frogs, they have sticky round toe-pads they use to climb and cling to twigs and bark.  They have an irregular “X” on their back, hence their scientific name, Pseudacris crucifer.  They are generally light brown in color, though they do have color-changing abilities.  Depending on their surroundings, they can darken or lighten their skin color to resemble their background.

Their call is a welcome sound, as it’s a sure sign that spring has arrived.


Peepers are found in woodland pools and ponds, preferably without fish to prey on their eggs, tadpoles and adults.  Males gather in these small pools by the hundreds, or even thousands.  Their chorus begins the first warm evenings of the season, starting in late February into late summer.  Only the male frogs call, averaging a peep per second.  They usually call in trios, with the lowest-pitched male starting the competition.  Those that sing the loudest and fastest are most likely to attract mates.  These nocturnal amphibians can be heard loud and clear up to a half-mile away.


The reason they can call so loudly is because of large “vocal sacs” under their chins.  They pump these sacs full of air until they look like a balloon, and then discharge the air with a powerful “peep.”  The easiest way to see Peepers is to look for these shiny oversized sacs, which nearly double their size when inflated.


After mating Peepers lay up to 1,200 eggs in clumps attached to twigs and aquatic vegetation.  The eggs may hatch in only a few days or up to two weeks, depending on temperatures.  Within two to three months, young tadpoles are transformed into young frogs and leave the pond.  They then take to the woodlands where they serve the useful purpose of hunting insects.


Peepers hibernate on land.  Like all amphibians they are cold-blooded and their body temperatures change in accordance with outside temperatures.  When temperatures drop below freezing, body parts also freeze and actually form ice crystals.  Vital organs though, as heart and lungs, are protected by a natural anti-freeze (glucose) they produce in their livers.


A variety of animals prey on Spring Peepers, including snakes, skunks and even larger frogs.  However, nothing is more devastating to a pond full of Peepers than a pesticide or herbicide spray.  A single application of either can wipe out an entire pond population of these fascinating tree frogs.  These welcome harbingers of spring are way too cool to let that happen.