Tuesday, October 11, 2011

Fall Dune Hike -- Post 1

Sunday I opened the museum for appointments and a few others who happened chance by. It was another glorious Indian summer day, so I decided to go for a hike.  I drove west on H58 and stopped by Sable Lake to snap a couple of photos from the overlook.

The tree canopy has completely recovered over parts of the now paved H58 between Grand Marais and Munising.

While hiking, I came across this three foot long garter snake. The Garter snake is a Colubrid snake common across North America, ranging from Alaska and Canada to Central America.  It is the single most widely distributed genus of reptile in North America.  The garter snake is the Massachusetts state reptile, is the only species of snake found in Alaska, and may be the northernmost species of snake in the world.  This snake is far ranging due to its unparticular diet and adaptability to different environments, terrain, and varying proximity to water.

Garter snakes, like all snakes, are carnivorous. Their diet consists of almost any creature that they are capable of overpowering: slugs, earthworms, leeches, lizards, amphibians, birds, fish, toads and rodents. When living near the water, they will eat aquatic animals. Food is swallowed whole. Garter snakes often adapt to eating whatever they can find, and whenever, because food can be scarce or abundant.

Garter snakes have complex systems of communication. They can find other snakes by following their pheromone-scented trails. Male and female skin pheromones are so different as to be immediately distinguishable. However, sometimes male garter snakes produce both male and female pheromones. During mating season, this trait fools other males into attempting to mate with these "she-males". This causes the transfer of heat which is an advantage immediately after hibernation allowing the "she-males" to be more active as well as to garner more copulations than normal males.

If disturbed, a garter snake may coil and strike, but typically it will hide its head and flail its tail. Although there is a small amount of venom delivered in a strike, the amount is not enough to impact humans.  These snakes will also discharge a malodorous, musky-scented secretion from a gland . They often use these techniques to escape when ensnared by a predator. They will also slither into the water to escape a predator on land.  Hawks, crows, raccoons, crayfish and other snake species (such as the coral snake and king snake) will eat garter snakes.

Being heterothermic, like all reptiles, garter snakes bask in the sun to regulate their body temperature. During hibernation, garter snakes typically occupy large, communal sites called hibernacula. Garter snakes go into brumation before they mate. They stop eating for about two weeks beforehand to clear their stomach of any food that would rot there otherwise. They then begin mating after emerging from brumation. The males mate with several females.  Males usually come out of their dens first.  As soon as the females emerge, they are surrounded by males who are immediately attracted to a sex-specific pheromone that attracts male snakes in droves.  Sometimes there is intense male-male competition that results in the formation of mating balls of up to 25 males per female. After copulation, a female leaves the den/mating area to find food and a place to give birth. Female garter snakes are able to store the male's sperm for years before fertilization. The young are incubated in the lower abdomen, at about the midpoint of the length of the mother's body. Garter snakes are ovoviviparous meaning they give birth to live young. However, this is different than being truly viviparous, which is seen in mammals. Gestation is two to three months in most species. As few as 3 or as many as 80 snakes are born in a single litter. The young are independent upon birth. On record, the greatest number of garter snakes to be born in a single litter is 98.

I also captured this image of a milkweed plant, and decided to open up a pod. Since it is October, I expected the seeds to be ripe and ready to spread in the wind.  The pod was not yet ripe, but provided a beautiful array of seeds.

Milkweed ia a genus of herbaceous perennial plants that contains over 140 known species. This plant is named for its milky juice, which contains alkaloids, latex, and several other complex compounds including cardenolides. Some species are known to be toxic.
Pollination in this genus is accomplished in an unusual manner. Pollen is grouped into complex structures called pollinia (or "pollen sacs"), rather than being individual grains or tetrads, as is typical for most plants. The feet or mouthparts of flower visiting insrects such as bees, wasps and butterflies, slip into one of the five slits in each flower. The pollinia then mechanically attaches to the insect, pulling a pair of pollen sacs free when the pollinator flies off. Pollination is effected by the reverse procedure in which one of the pollinia becomes trapped within the slit of another flower.

Asclepias species produce their seeds in follicles. The seeds, which are arranged in overlapping rows, have white silky filament-like hairs known as pappus, silk, or floss. The follicles ripen and split open and the seeds, each carried by several dried pappus, are blown by the wind. They have many different flower colorations.

While walking near the dunes, I spotted this perfect evergrreen showing in sharp contrast to the golden leaves in the background.

1 comment:

  1. Awww can I copy the picture of the snake, he is so bright and cheerful. I picked one up once and it sprayed that musk smell. They are shy but will allow themselves to be handled if they have to. That was the only time one emitted the musk smell. That was years ago and I am not sure that I would pick one up nowadays.