An online resource based on the award-winning nature guide

Animal Adaptations

Porcupines Giving Birth

4-18-13 porcupine IMG_9203It’s not easy being a female porcupine. You mate in the fall and are either pregnant (7 months) or lactating (4 months) for the next 11 months before you have one month’s break and begin this cycle all over again. This time of year porcupines are giving birth to one young that is covered in fur and quills and weighs about a pound. The young porcupette is born headfirst in a sac, in order to protect the mother from quill damage. Its quills are soft at birth, but harden within an hour. (Thanks to Kay and Peter Shumway for photo op.)


Spring Peepers Emerging

4-8-13 spring peeper2 IMG_7463Sitting on top of the snow, still as a statue, a spring peeper gathers strength to make the long trek to open water, where, if it is a male, it will exercise its voice for the first time in many months. Like the gray treefrog and wood frog, spring peepers can freeze as solid as a rock for several months during hibernation and then, on a warm day, thaw out in a few hours and resume a normal, active life.  The formation of glucose and ice crystals that form outside of cells enable this phenomenon to occur.  Once hibernation has come to an end, peepers seek out wetlands, vernal pools and ponds to breed and lay eggs before they return to their home on the forest floor.


Painted Turtles Basking

3-27-13 painted turtle IMG_7777Hibernation has come to an end for painted turtles in central Vermont, or at least for the early risers. Painted turtles actually became active a while ago, beneath the ice before ponds were completely thawed. Once some of the ice melts, they are quick to climb up and bask in the sun on any available floating log or rock, or even on the melting edge of the ice. Having spent the winter in the mud at the bottom of the pond at the rather brisk temperature of 39 degrees F. (at 39 degrees F. water achieves its greatest density and sinks to the bottom of ponds, which is where the turtles are), painted turtles are more than ready to get warm. Like black bears, painted turtles find March and April the most challenging months of the year. More of them die now than at any other time, due primarily to a shortage of food.


Black Bear Hibernation Ends

3-20-13 black bear track IMG_7204Recent discovery of black bear tracks and scat confirm that hibernation has come to an end, at least for some bears. During the winter black bears lose an average of 23% of their body weight. Because there is a scarcity of food when they emerge from their dens, black bears continue to subsist off the fat that they put on last fall, and thus continue to lose weight. The diet of black bears is high in carbohydrates and low in proteins and fats. When hibernation is over, they head for any available succulents and protein-rich food, including bird feeders.


White-tailed Deer Diet & Digestion

11-30-12 deer eating IMG_6035A white-tailed deer’s diet consists of a wide variety of herbaceous and woody plants, the ratio of one to the other being determined by the season. Fungi, fruits and herbaceous plants form much of the summer diet. Dried leaves and grasses, acorns, beechnuts and woody browse are important autumn and early winter food. After snowfall, the winter diet consists mostly of woody browse (twigs, leaves, shoots and buds) from many different trees (maples, birches and cedars among them). Come spring, deer eat buds, twigs and emerging leaves. Deer are ruminants (as are cattle, goats, sheep and moose). They have a four-chambered stomach, which is necessary in order to digest the cellulose in the vegetation they consume. Food goes first to the rumen, the first of the four chambers, which contains bacteria and other microorganisms that help digest the cellulose. Food is circulated from the rumen back to the deer’s mouth by the second chamber, or reticulum, and the deer ruminates (“chews its cud”). The third chamber, or omasum, functions as a pump, sending the food to the final chamber, the abomasum, where the digestion process is completed.


A Great Christmas Present!

If you’re looking for a present for someone that will be used year round, year after year, Naturally Curious may just fit the bill.  A relative, a friend, your child’s school teacher – it’s the gift that keeps on giving to both young and old!

One reader wrote, “This is a unique book as far as I know. I have several naturalists’ books covering Vermont and the Northeast, and have seen nothing of this breadth, covered to this depth. So much interesting information about birds, amphibians, mammals, insects, plants. This would be useful to those in the mid-Atlantic, New York, and even wider geographic regions. The author gives a month-by-month look at what’s going on in the natural world, and so much of the information would simply be moved forward or back a month in other regions, but would still be relevant because of the wide overlap of species. Very readable. Couldn’t put it down. I consider myself pretty knowledgeable about the natural world, but there was much that was new to me in this book. I would have loved to have this to use as a text when I was teaching. Suitable for a wide range of ages.”

In a recent email to me a parent wrote, “Naturally Curious is our five year old’s unqualified f-a-v-o-r-I-t-e  book. He spends hours regularly returning to it to study it’s vivid pictures and have us read to him about all the different creatures. It is a ‘must have’ for any family with children living in New England…or for anyone that simply shares a love of the outdoors.”

I am a firm believer in fostering a love of nature in young children – the younger the better — but I admit that when I wrote Naturally Curious, I was writing it with adults in mind. It delights me no end to know that children don’t even need a grown-up middleman to enjoy it!


Beavers Ice-Bumping

Ice is starting to form on ponds, and days are numbered when beavers can be out grooming themselves on land or eating freshly-cut branches.  As long as the ice is thin enough to crack by swimming up under it and bumping their heads against it, they will do so, for soon it will be thick enough to lock them into their pond. Life under the ice is challenging.  At 32 degrees F. a beaver’s resistance to heat loss in water is about 1/8th of that in air at the same temperature. This is due to the fact that its fur is compressed in the water, allowing the insulating air between the hairs to escape — a beaver’s pelt accounts for about 24% of its total insulation in water and body fat is responsible for the rest.  Heat is also retained through a beaver’s tail and hind legs, which serve as heat exchangers.  In the summer, a beaver can lose 25% of its body heat through its tail, but it only loses 2% in winter. Even so, it’s no wonder beavers risk getting a headache in order to see the sun for the last time until spring.


Rub-urination

On the inside of the hind legs of all white-tailed deer are glands called tarsal glands.  They consist of a tuft of long hairs coming from an area of skin in which are located glands that secrete a fatty substance.  This fatty substance adheres to the long hairs.  When deer urinate, they often assume a crouched posture, causing their urine to run over these hairs.  The lipid, or fatty material, on the hairs causes some of the urine that runs over them to remain there. Excess urine is licked off by the deer. The combination of fatty material and urine gives the glands a unique smell (not the typical deer urine smell.) During the breeding season mature bucks urinate on the tarsal gland much more frequently, and don’t lick off the excess urine, which creates a distinctive rutting odor .  This practice is referred to as “rub-urination.”  All deer urinate on these glands throughout the year.


Black Bear Tracks

 

This may well be the last month until spring in which signs of active black bears can be found – cold temperatures and a poor beechnut and acorn crop may hasten their retreat into their dens.  A black bear’s track is fairly distinctive, if only due to its size: 3 ½”- 6” wide by 4”-9” long.  Black bears are flat-footed, or plantigrades, and thus you see more than just the toe imprints in a track; the heel pads of the hind feet are larger than those of the front feet.  Black bears have five toes on each foot. The smallest, outside toe often doesn’t register.  Long, curved nails on a black bear’s front feet are used for marking trees and climbing; the hind feet nails are much shorter.


Cecropia Moth Cocoon

This past summer there seemed to be more giant silkmoths than usual, including Cecropia Moths (Hylaphora cecropia).  (see http://naturallycuriouswithmaryholland.wordpress.com/2012/06/04/cecropia-moth-2/ ). Assuming many of these moths bred and laid eggs, and that most of the larvae survived, there are probably a large number of Cecropia cocoons in our woods.  Even so, it is not an easy task to find them, as they are so well camouflaged, and are often mistaken for a dead leaf.  Cecropia caterpillars spin silk and fashion it into a three-inch long, tan cocoon (giant silkmoths make the largest cocoons in North America) which they attach lengthwise to a branch or stem.  There is a tough but thin layer of silk on the outside, which protects an inner, thicker and softer layer of silk on the inside.  The caterpillar enters the cocoon through loose valves it makes in both layers, which are located at the tip of the cocoon’s pointed end.  Shortly after the larva crawls inside both of these layers, it pupates.  Its skin splits, revealing a dark brown pupa. For the rest of the winter and most of the spring, it remains a pupa.  In early summer it metamorphoses into an adult moth and exits the cocoon through the same valves  through which it entered.

 


Flying Squirrels Visiting Bird Feeders

Are you finding that the amount of seed in your bird feeders drops precipitously after dark?  Those of us in black bear country are advised to bring feeders in at night so as not to attract bears, but occasionally several hours of darkness have passed before I remember to do so.  When that happens, the feeders inevitably need filling.  What stealthy critter is visiting once the sun goes down?  Very possibly, flying squirrels are the culprits.  These nocturnal rodents can glide as far as 295 feet from tree to tree, or tree to ground.  They stretch their legs out and direct their glide by controlling the position of the flap of skin (patagium) that extends from the outside of the wrist on the front leg to the ankle of the hind leg on both sides of their body.  Their broad, flattened tail acts as a parachute, rudder, stabilizer and brake during the glide.  Feeders are rarely far enough from a tree to necessitate a glide – a short leap does the trick.  If you feed birds, try shining a light on your feeders after the sun goes down.  You may very well be treated to the sight of several flying squirrels helping themselves to your sunflower seeds and suet.


Eastern Chipmunks Gathering Food

By the end of this month or the beginning of November, most Eastern Chipmunks will have gathered and stored their winter food supply underground in a special chamber which they will visit every two or three weeks throughout the winter, grabbing a bite to eat.  Up to half a bushel of nuts and seeds can be stored here, which means many trips from the food source to the larder.  In order to minimize the number of trips, chipmunks  cram their cheek pouches as full as possible.  The contents that researchers have found in one chipmunk’s two pouches include the following (each entry represents the contents of one chipmunk’s pouches):   31 kernels of corn, 13 prune pits, 70 sunflower seeds, 32 beechnuts, 6 acorns.


Beavers Gathering Winter Food Supply

Shorter days and longer nights trigger a flurry of activity for beavers.  There is a lodge to be built, rebuilt, enlarged or repaired and a dam to be built, repaired or reinforced.  As, or more, important than these tasks is cutting, gathering and transporting a supply of food for winter. Once the pond is frozen, the only food available to beavers is that which they have stockpiled under the ice.   Thus, beavers spend many an autumn night adding to a growing pile of submerged branches close to the lodge.  More thought is put into the harvesting of a winter food supply than one might imagine.  Before cutting down a tree a beaver often tests its readiness by biting into the bark.  If it is not in just the right condition — for instance, if there is still too much sap in the tree — they may speed up the drying of the bark by girdling it, and returning in several days to cut it down.  If limbs and branches are stored underwater before the bark is ready, they will ferment and sour, making them unfit for food.


Praying Mantis

Between being able to swivel its head nearly 180 degrees, and having two large compound eyes and three simple eyes, the Praying Mantis (Mantis religiosa) misses very few insects within reach.  Due to its green or brown coloration, the Praying Mantis is well camouflaged as it lies in ambush or stalks its prey.  Spines, tooth-like tubercles and a claw near the tip of each foreleg enable this predator to have a secure grasp on the moths, crickets, grasshoppers, flies, and other insects it consumes.  (A Praying Mantis in Pennsylvania was photographed successfully capturing a Ruby-throated Hummingbird!)  The pictured female is heavy with hundreds of eggs she will soon lay in a foam case she whips up.


Moose in Rut

The mating season for moose (Alces alces) is just starting, and it peaks around the end of September or the first week in October.  By this time bulls have shed the velvet that provided a blood supply to their antlers while they were growing during the summer.  Occasionally you see the remains of the velvet hanging from their antlers at this time of year (see photograph).  During mating season, bulls are rushing through the forest, seeking a receptive cow and engaging in mock battles with other bulls for the female’s attention.  A bull uses his antlers in these challenges, engaging in “antler-pushing” with other males.  He also uses his antlers as a tool for thrashing brush and for rooting plants from the bottom of ponds.


How Great Blue Herons Stay Cool

Birds have a number of ways of keeping cool, which is a good thing,  given the number of hot days we’ve experienced this summer, and probably for summers to come.  They don’t sweat, nor do they pant, but birds do have several  behavioral adaptations which reduce their temperature.  Often, while exposed to the relentless heat of the sun, Great Blue Heron nestlings resort to what is called gular fluttering.  They open their mouths and “flutter” their  neck muscles, promoting heat loss – an avian version of panting.   An even easier behavior to observe is the position Great Blue Herons will often assume on a hot day.  They droop their wings (see photograph) while standing, which allows air to circulate across their body and sweep away the excess heat.


Snake Eyes

You can often tell whether a snake is active in the day (diurnal) or during the night (nocturnal) by looking at its eyes. Diurnal snakes, such as the pictured Common Gartersnake, typically have round pupils and moderate-sized eyes. Many nocturnal snakes have large eyes and many also have vertical, elliptical pupils. A round pupil is able to close tightly to a pinpoint opening, allowing a minimum amount of light to enter the eye on very bright days. In contrast, a vertical pupil can open wider than a round pupil to allow more light to enter the eye, a useful adaptation for night vision.


How Snails Feed

Most terrestrial snails are herbivorous, feeding on a wide range of vegetation. The snail’s mouth is on the bottom of its head near the shorter pair of tentacles. Snails (and all molluscs) consume their food not with mouthparts, like insects, or teeth, like mammals, but with a rasping tongue or radula. Snails don’t bite their food, but rather, rasp or scrape it. The radula is covered with rows of tiny “toothlets” which rasp particles away from vegetation and move them back towards the snail’s gullet. Different species of snails have differently-shaped toothlets. The radula is used by the snail not only to process food, but to clean bits of dried mucus from its shell. Supposedly if you listen hard, you can actually hear a rasping sound when the latter is occurring. (If you look hard, you can just barely see the orange radula of the land snail in the photograph.)


How Toads Breathe

Like all amphibians, toads breathe through their skin as well as with their lungs. When a toad is inactive the skin usually absorbs enough oxygen to meet its needs. During and after activity a toad often supplements its supply of oxygen by actively breathing air into its lungs. Unlike mammals, amphibians do not make regular and rhythmic breathing movements but bring air into their lungs spasmodically as the need arises. Air enters the toad’s mouth through its nostrils, and by raising the floor of its mouth, the toad forces the air into its lungs. (Photo is of an American Toad.)


Moose Flies and Moose

My recent quest for finding moose was successful – and my most striking observation, other than their imposing size, was the presence of a multitude of flies on and around the hindquarters of every moose I saw. I assumed they were deer flies, but they didn’t appear to be bothering the moose and research revealed that, in fact, they were moose flies, Haematobosca alcis. These flies can be seen throughout the spring and summer in dense swarms over and on the rumps of moose — five hundred or more may accompany a single moose. Unlike most other biting insects, both male and female moose flies feed on their host’s blood. Although not considered a serious pest (moose tend to pay little attention to them), moose flies may be responsible for sores often found on the hind legs of moose. It is thought that female moose flies may be stimulated by gases released by the moose when it is defecating, after which the female flies descend and deposit eggs into crevices in the moose’s scat.


Spittlebugs

This slideshow requires JavaScript.

Have you ever poked around inside one of those masses of bubbles that you see on grass and other plant stems? If so, chances are that you have discovered that an insect actually lives inside this frothy home – the immature stage (nymph) of a Spittlebug. It hangs head down while piercing the stem of the plant and ingests the sap. Because the sugar content is often very low, the nymph must drink a lot of sap in order to get the nutrition it needs. As a result, the Spittlebug pumps out the excess water from the tip of its abdomen, which amounts to 150 – 300 times its weight every 24 hours. During this process, oxygen and nymphal secretions cause the water to have a sticky, bubbly quality, and these sticky bubbles pour down over the nymph, creating a moist home that prevents the Spittlebug nymph from drying out and that discourages predators as it tastes bad. Once it has matured, the nymph metamorphoses into an adult Spittlebug (also called a Froghopper) and flies away.  (Photographs are of:  spittlebug “spit,” spittlebug nymph and adult spittlebug emerging from nymphal skin.)


Porcupine Foot Pads

Given the amount of time porcupines spend in trees, it’s not surprising to see that their feet are well adapted for climbing.  Long, curved nails that grip the bark, as well as “pebbly” foot pads designed to prevent slipping allow this prickly rodent to climb just about anywhere it wants to.  (Hind foot pictured.)


Cryptic Coloration

Can you find the brown creeper that’s on the trunk of this black cherry tree? This is cryptic coloration, a form of camouflage in which an animal blends into its environment, at its finest.  A forager of insects and spiders tucked away behind and in the crevices of bark, the brown creeper starts its search at the base of a tree, climbing upward and often spiraling around the trunk until it nears the top.  It then flies to the base of a nearby tree to begin the process again. As W.M.Tyler wrote in 1948 in Bent’s Life Histories of N.A. Birds, “The brown creeper, as he hitches along the bole of a tree, looks like a fragment of detached bark that is defying the law of gravitation by moving upward over the trunk, and as he flies off to another tree he resembles a little dry leaf blown about by the wind.”  


Winter Survival Strategy of Flying Squirrels

 

During the winter flying squirrels often huddle together in large communal nests, sometimes with populations numbering over two dozen squirrels, in an effort to keep warm.  Two years ago 22 of these nocturnal creatures spent the majority of the winter in my log cabin, doing just that.  Although flying squirrels do not hibernate, if temperatures become too severe the squirrels will enter a state of torpor until temperatures return to normal.


Follow

Get every new post delivered to your Inbox.

Join 1,492 other followers