The Habitat Directs Animal Adaptations

by Dave Hanks

How does a species survive when it’s too hot, too cold, too wet or too dry? Over a period of years, the individuals that can stand the conditions better survive. Because it’s difficult to reproduce when one is dead, those with the best survival traits do the reproducing. Gradually the resulting offspring become adapted to withstand the existing environmental conditions. Behavior is also an adaptation. (i.e. shade seeking to get out of the sun, seeking cover to get away from a cold wind, or trying to blend in with one’s surroundings, are some examples).

TOO HOT: Longer, slimmer appendages that allow the blood to be closer to the surface to expel heat, and fat deposits in one spot to avoid covering the body which prevents heat loss. Humps on camels and fat tails on desert sheep are prime examples.

TOO COLD: Just opposite of too hot. These animals have short limbs, thick bodies, with their fat distributed evenly over their bodies. They are usually bigger (i.e. Alaska Moose are larger than Idaho Moose) which lowers the percent of surface area in relation to size and preserves body warmth.

TOO DRY: These have a very interesting adaptation to satisfy their water needs – they make their own from the carbohydrates they eat. A carbohydrate molecule is simply 6 molecules of water with 6 carbon atoms attached. Kick the carbon atoms off the molecule and you have water. We humans do the same, but get rid of the water, which is necessary to get rid of other waste products and cleanse our systems. Hot climate animals have to have devised other means of cleansing their systems

TOO WET: These animals develop sleek, steam lined bodies, appendages for movement in water, and counter shading (Dark on dorsal surface and light underneath on their ventral areas – camouflage from both above and below).

The Greater Yellowlegs (Pictured) is a bird of THE WET. Notice its white belly and dark, mottled top. It’s well camouflaged.

The Effects of TORPOR or Lack thereof

There are several definitions of torpor: sluggishness, apathy, suspension of physical powers, or dormancy. ESTAVATION is a summer torpor that occurs with species that live in warm climates. It occurs during the hottest time of the year. HIBERNATION is winter torpor. We, here in Idaho, are most familiar with this type. All species go through some type of torpor. Nocturnal animals sleep during the day, and diurnal species do the opposite.

Torpor is an involuntary thing. The HYPOTHALAMUS is the part of the brain that controls body temperature, hunger, sex drive, moods, and sleep (TORPOR). Changes in the weather or fatigue can stimulate the onset of torpor. When waking from torpor, hibernating animals waken very slowly and are very groggy.

HISTAMINE is an organic, nitrogen compound involved in immune responses and physiological functions. It is believed that the production of this chemical is a natural inducer of hibernation (torpor).

Bears and many rodents are not true hibernators. Their heartbeats and temperatures do not go down to the degree that other hibernators do. This allows them to awake periodically to eat from a food cache, defecate, and drink.

An interesting study with chipmunks has shown that lack of torpor can kill.When winters are warmer than usual, these rodents fail to go into their natural torpor cycle. The results are that about a 90 percent loss of life occurs within a population that doesn’t get the required sleep. This is contrasted against a 90 percent winter survival rate with populations that get the needed sleep.

Anthropomorphism

by Dave Hanks

The above term means to give a human interpretation to an animal action. For example: When a Baboon looks like it’s smiling and happy, don’t be deceived. It is showing you its teeth. If it can get close enough, it will bite you. What we would normally interpret as friendliness is really a warning to keep our distance. When Bison do weird tail movements, they are not taking care of an itch. It, also, is a body language warning. And, even though we find dogs irresistible; their open mouth, with tongue hanging down, does not necessarily mean they are in a happy, loving mood toward us. They are merely expelling body heat.

I am always amused by those who treat their pets as if they actually reacted to things like a human would. To dress a dog or cat in a shirt or any other type of clothing is unnatural. Pets do enjoy being inside with the people that love, rub, and caress them. But they are not normally adapted to house life; nature has equipped them for an outdoors existence. When we lived in Montana (if the wind was not blowing) our cattle would “shun’ the sheds and stay out in the open – even if it was 30 degrees below zero.

One can love animals and yet know very little about their needs. Some folks can’t get past placing their own wants upon them. The move to prevent the management of wild horses, because of a misguided love for them, is a prime example of loving something to its determent. The horses destroy the range for themselves and the naturalized wildlife of the area.

Human ethics and morals do not apply to animals. Their DNA has programmed them to act in certain ways typical of their species. Children’s stories and Hollywood have, in many instances, been responsible for feelings that have been held on to well into adulthood. A species is neither as bad nor as good as depicted in story books. Large predators are not blood thirsty killers, but act only as nature has intended. Understanding this and granting them their space will usually result in a peaceful co-existence between them and us – a thing that the Indians have long understood.

This baby RACCOON (pictured) looks so lovable that the urge may be to try to pick it up. Do so and you’ll find out how it can scratch and bite.

baby raccoon

The Sense of Smell: A foremost asset to most animals

by Dave Hanks

The sense of smell may rank below sight and hearing for humans, but it is the most developed and depended upon sense in a great number of animal species. In jungle habitats, 99 percent of the animals depend on chemical trails and bits of odor released into the air or water. This is not surprising, as heavy vegetation limits one’s visual abilities. Insects are the masters at scent identification. The many types of ants have multiplied to where they comprise 70 percent of all insects in the tops of jungle trees. Much of this success can be attributed to their acute sense of smell. Snakes, fish, and many mammals also have highly developed olfactory centers.

Smell and taste are often experienced together, but each is separate from the other although thought to be connected. Inhaled molecules passing through the nasal passages come in contact with the olfactory bulb. Nerves then relay the message to the brain. Observing the size of a species olfactory bulb (relative to body size) can predict the acuteness of this sense in each species.

In mammals: bears, canines, and especially elephants rely heavily on scent signals. One such canine, the RED FOX, has a terrific sense of smell. This is important because foxes, although they can readily detect movement, are short sighted. Using smell in tracking prey, it becomes a lean, mean, hunting machine. Scent signals help it to relocate food caches, and to avoid bobcats, bears, and wolves. It has, also, been diligently hunted by humans and its acute senses have given it the reputation of being the embodiment of cunning.

The Red Fox is 1 ½ to 3 feet long and around 14 pounds. However, the farther north they are found, the larger they are. It is reddish-orange with whitish fur on its neck and chest. The tail is long and bushy. Regardless of any color variation, its tail is always tipped in white. As a family oriented animal, both the male, female, and older offspring cooperate in the care of the pups.

Vulpes following a rodent scent trail

Vulpes following a rodent scent trail

Taiga: “Land of the Little sticks”

Taiga is Boreal forest, or in Russian perspective – “the land of the little sticks”. It is so called because the tree growth is stunted and skinny. Permafrost prohibits deep root development and trees usually only grow to around 15 to 20 feet tall. This Biome is the largest in the world – covering the northern areas of Canada, Russia, and Europe. The major trees in the Taiga are Black and White Spruce.

This Biome is characterized by many forest fires, but the trees recover quickly and re-growth is fast. Summers are warm, rainy (12 to 30 inches), and temperatures stay around 70 degrees because of the continual daylight. Winters, however, are another story. They are dark, snowy, and very cold. At this time temperatures range between 30 to 65 degrees below zero.

Taiga animals either migrate south or hibernate. Only a few withstand the harsh winter conditions. Caribou come south, from the Tundra, to winter amid the trees and to get some protection from the wind. Lynx, Snowshoe Hare, Wolverine, and fox are some other species that withstand the weather. Grizzlies and Black Bears are snuggly ensconced in their hibernation sanctuaries.

Summer invites many species of birds to nest, reproduce, and use the continual summer daylight to give them more time to hunt the food for the never satisfied appetites of their young.

We have experienced the vastness of this part of the world on four different occasions when we were in the Yukon Territory. Once we traveled 900 miles north on a dirt road and into the Arctic Circle. The broad expanse of the landscape makes one realize just how insignificant one is!

Black Spruce amid the wet – permafrost causes poor drainage

Our Yard: Cottontail Habitat

We have a bunch of Cottontails,their tails are silky white – I see them every morning, before the sun is bright

They especially like our bushes,and the cover that they give – They sneak back and forth from them, what a way to live!

They are so very cute, so cuddly and so plump – And when they hop away I see, The white bobbing of each rump

The mornings promise excitement, from the wild things on our place – And I’m so ever grateful, that they seem to find the space

To romp around so freely, it makes me feel so good – But with a yard like ours, I guess I knew it would!

There are 16 species of cottontails, and these rabbits only live for 12 to 15 months. Only one in a hundred will survive to see its third fall. Their short life span, and the heavy predation upon them, requires these critters to be heavy reproducers. They may raise as many as 6 litters a year. Breeding starts in March and lasts through early autumn. Their nests are not dug, but are slight depressions scratched out under dense vegetation. The doe lines it with dry grass and her fur. She gives birth up to eight blind, furless young in each litter. The bunnies grow rapidly and are totally independent at five weeks. On the average, only 15 percent of the young will survive their first year.

Cottontails have very keen eyesight and hearing. They will usually freeze when they sense danger, but will flush if approached too closely. Movement is usually accomplished by short hops, but they can run at speeds up to 18 miles per hour over short distances – their endurance is limited. They will often zig-zag to confuse a pursuing predator.

Cottontails eat grass, ferns, herbs, and your garden plants. They can become a threat to young growing vegetables – like our young corn shoots – which require us to surround them with some type of protection. This reminds me of the Peter Cottontail stories and the “scritch-scratching” of Mr. MacGreagor’s hoe.

A Mountain Cottontail in our yard

A Mountain Cottontail in our yard

Muskrat: The Beaver’s Lesser Cousin

Muskrats seem like little beavers – both are rodents, and both are in the same family. Both have similarities, but the Muskrat is smaller and has a round tail instead of a flat one. Their houses are even similar, except the Muskrat’s is constructed of herbaceous vegetation (often Bulrush) instead of wood.

I don’t know how many times we have spotted this rodent, rushed to get a photograph, only to have it submerge out of sight for a long time. It can be a long time, because they can stay under for as long as 15 minutes. If that isn’t enough, they can always enter a burrow dug under the water’s bank. The photos we have are strictly the result of good luck.

These animals seek wetlands where the water is 5 to 6 feet deep with plenty of sedges. They are mainly herbivorous but will eat frogs, clams, and small fish. The interesting thing about their diet is that they consume up to a third of their body weight each day – a tremendous amount for a mammal, although equaled and surpassed by birds.

They have a couple of unusual traits: communicating through their musky odors and heterothermia. This is the control of the blood flow to their feet and tail. This allows those parts to remain cooler than the main body.

Muskrats only live about 3 years in the wild. This calls for fast reproduction and the reaching of puberty as early as 7 months. Heavy reproduction is also necessary for the species survival because so many predators find this animal a very desirable food item.

muskrat at An early breakfast of Bulrush

An early breakfast of Bulrush

Eyes: Windows to the Personality

When I do photography, I have always tried to focus on an eye. A bright, clear eye in a picture makes the photo come alive – without the eye the animal is incomplete. Eyes are also a body adaptation that furnishes a key to how a species lives and survives.

For instance, a predatory life style can be ascertained by noticing the forward looking, binocular vision eyes. The same can be concluded for prey species with their eyes more to the rear, or actually on the side of the head, which allows detection of something approaching from behind. Nighttime predators have enlarged eyes that have many rods in them. An owl’s eyes are so big that they make up a third of the head. Other feathered predators, such as eagles and hawks, usually have yellow eyes. The yellow is the result of an oil-like inner eye secretion that is yellow, and it acts the same way as a filter on a camera does – an adaptation for an animal that must deal with bright sunlight. The placement of the eye is positioned to give each beast an advantage – i.e. giraffes with eyes situated to look down toward the dangers from ground level; or eyes placed on top of the head – such as frogs, hippos, and alligators that live in water. Their bodies can remain submerged with only their eyes out of the water. The Crocodilians may appear like a floating log, but they are well aware of any surface activity. Some lizard’s eyes are not on the same level with each other, giving them a wide range of vision.

Many animals have two eyelids: the outer one that closes the eye to light and other invasions, and an inner nictitating membrane which allows some light in and therefore some vision while still giving partial protection to the eye ball. Snake eyes have no eyelid and that is probably one reason that they appear eerie. They deal with light by the construction of their pupil. Each species pupil is adapted to the habitat it lives in: round, where light is no problem; elliptical vertical, against light from the side; elliptical horizontal, where there is more over head light; and pupils punctuated in a line of tiny holes, is an adaptation against extremely bright conditions.

Yes, eyes really are the doorway to an organism’s being!

The American Alligator – An example of eye adaptation

The American Alligator – An example of eye adaptation

Animals Tend to be Opportunistic

Many things that have been held to be fact, are not true at all. In my first year of school teaching I depended heavily on the text book, only to learn at a later date that some of the facts were not really facts. In our travels, we are constantly regaled to not feed birds, and other forms of animal life because it will hinder their survival in the wild. I just don’t believe this anymore. I have been around animals and observed their behavior all of my long life, and have learned that they will do whatever is necessary to survive or make their existence easier. In short, animals are opportunistic!

We have observed Western Tanagers, with their insectivore beaks, eating seeds. Now that just isn’t supposed to be. Meat eaters, such as Fox or Coyote, will often consume non-meat items. Great Blue Herons are supposed to eat small fish, frogs, and other small aquatic organisms. Much to my surprise, I once watched for some minutes a heron, on a park lawn, carefully creeping up on a ground squirrel hole. What, I wondered, was it doing? Suddenly its head shot out and into the hole. Out it came with a large ground squirrel in its beak, which it swallowed in one mighty gulp.

Little kids will all say that bears eat honey and that may be so, but in reality (and this is shocking to some) they eat a large quantity of grass. It is interesting to watch them on a hillside grazing like cattle.

But of course, we all know that Grizzlies are opportunistic and will consume almost anything. Meat is a big favorite – their “Ice Cream food” so to speak. However, other than squirrels and such, and the new born, they are poor predators. Scavenging on the larger winter-killed beasts is common after emerging from hibernation. The Grizzly pictured is feeding on carrion at the side of a pond. When I saw the bear moving to it, I ran and hurriedly walked for about a mile (packing a heavy camera and tripod) to witness the spectacle that was to occur. Now, that is hard on a 75 year old man, but it was well worth the effort!

Grizzly Bear Gorging upon a carcass

Gorging upon the carcass

Masking Factors

MASKING FACTORS are those items in a habitat that compensate for conditions that might prevent a specific species from surviving in that habitat. Example: The tiger is normally a cold climate animal, but the Bengal Tiger lives in hot, hot India. They keep close to forested (shady) areas which have access to water. The mid-day hours are spent languishing in that water. The ponds are one of the tiger’s masking factors and are essential for its survival in India.

Wind allows Mountain Goats to stay safe from predators in the winter. The vegetation on wind-swept cliffs is now assessable to the goats, and they can feed without descending into dangerous bottom-lands.

Large rocks can be an important masking factor for Marmots and Pika – vegetarians that could find food more easily in more open areas. Too far away from the rocks, and they become the food for carnivorous enemies.

The little Rock Wren also uses large rocky areas. It is an insectivore and spider eater. Not only will it take insects out of spider webs that are formed on the rocks, but will also eat the spider. As a ground feeder, it is vulnerable to overhead, as well as terrestrial predators, and the rocks provide a handy escape. The bird will make a pathway out of small, flat stones (a pavement so to speak) to its nest cavity within the boulders. The exact reason for this behavior is not known.

Two interesting side notes about this species are: 1 – It never drinks. It gets the necessary moisture from the insects it consumes and 2 – Its ability to sing. They are quite the songsters. They have a repertoire of over 100 different variations to their song.

A Rock Wren in his camouflaged coat

A Rock Wren in his camouflaged coat