Crepuscular Animals

Curve Billed Thrasher at Twilight

I love new, interesting words, don't you? When reading about snakes found in Arizona, the word  "crepuscular" appeared in the text, which of course triggered my overactive wonder muscle. I  had never heard this delightful adjective, used to describe creatures who are active primarily during the most glorious time of day... twilight...gentle, soothing twilight. Not quite nocturnal or diurnal, the animals who prefer this time are unique.

Twilight is a golden package of fleeting moments, found like book ends on each side of the day.  In the morning, it seems to embody the beauty and hope of a new fresh day, and in the evening, it gently wraps the day in a quiet, ethereal light, spilled alongside deep shadows across the landscape.  It is a time for seeing and hearing animals in a way unlike any other. Many photographers prefer the soothing, natural light that descends in the hour near twilight, a time when our cameras seem to do their best work.

One notable crepuscular desert dweller is the Javelina, or Collard Peccary.  I have only seen them during twilight hours. Unless sick, javelinas will travel in bands of 6 - 12 animals led by a dominant male. They have many incredible design features, such as their ability to eat prickly pear, spines and all. Javelinas derive most of their water from the plants they eat, so juicy prickly pear are among their favorite.  Watch for prickly pear plants that look like they have been torn versus cut or barrel cacti that have been overturned with the flesh scooped about like a tunnel into the underside.

 Javelinas are not considered dangerous if left alone, but an entire band can be aggressive and unpredictable, and if provoked, may attack when there are young or wounded among their members. They also have terrible eyesight, and use their sense of smell to communicate, so you will usually smell the musky scent of a javelina before you see one. They have several scent glands, which are located below each eye and on their back/rump. The glands release a strong odor when marking territory, members of their group, or when they become alarmed or excited.

The hour leading up to evening twilight is my favorite time to trek in the desert.  The harsh mid-day sunlight softens into a warm glow, and as the air cools, a playful breeze carries the sound of owl hoots and cricket songs. Bats and Nighthawks dance overhead, cotton tailed rabbits and other small mammals disappear into the shadows like children heading inside after a long day of play. Although seen other times of the day, Bobcats, Black Tailed Rabbits, as well as some snakes and birds are also considered crepuscular.  Many snakes are nocturnal during the hot summer, crepuscular in the spring and fall.

As you trek at twilight, watch for interesting crepuscular creatures, but remember that it is their feeding time, so try not to disturb them.  In the dim light, gaze with wonder at the unique happenings found only at twilight.

References and Resources
Earth Sky - What Exactly is Twilight?
Animal Sake
Desert USA - Collared Peccary
A-Z Animals - Collard Peccary
National Park Service - Javelina

Images: Sharon Pegany

Cultivate Wonder... Discover Design

Gopher Snake or Rattlesnake?!!!

Watch your step! Our reptile friends are apparently out in full force.  Today, we were out hunting for interesting rocks with our rock-hounding niece Emily and inadvertently came upon a long snake stretched out across our path.  Our first reaction was to stop, back away and mentally run through our internal rattlesnake identification checklist. Fortunately, this long, limber snake had a pointy head and tail, as well as round pupils.  Here in the west, it is commonly known as a Gopher Snake, but is closely related to and often called a Bull Snake.

Due to their length, coloring and markings, this non-poisonous snake is often mistaken for a Rattlesnake. Gopher Snakes and Rattlesnakes both help keep rodent populations under control and are essential for the health of the desert eco-system. As a desert dweller, it is important to learn the differences between a venomous Rattlesnake and a non-venomous Gopher Snake.  One is helpful in your outdoor landscape, and the other is better suited to the open desert.

Head
Rattlesnakes have triangular heads, with facial heat sensing pits that look like nostrils.
Gopher Snakes have narrow, rounded heads, although if threatened, they can flatten their heads to mimic a Rattlesnake.

Eye
Rattlesnakes have vertical, slit pupils, like a cat.
Like most non-venomous snakes in the US, Gopher Snakes have rounded pupils

Tail
Rattlesnakes have an ornate cluster of rattles on the tail which grows every time an old skin is shed. . Young rattlers do not have a "rattle" until they shed.
Gopher Snakes have a pointy tail, but because they mimic rattlers, it may be hard to see their tail if they are vigorously shaking it.

Body
Rattlesnakes are generally bulkier with a thick middle that tapers on both ends.
Gopher Snakes can grow much longer than Rattlesnakes, up to 8 feet, whereas Rattlers usually top out at about 4 feet. Gopher snakes are also slimmer and more limber looking than Rattlers.

No matter what kind of snake you encounter in your tracking adventures, always leave them alone. Even the non-venomous Gopher Snake can strike with a painful bite. However, most snakes are content to slip away without an encounter and will only bite if provoked or surprised.   These amazingly designed creatures are a treat to see in their native habitat if we use caution and give them plenty of space.  When we track wonder in the wild, it is up to us to diligently watch where we place our feet and hands.  As you move across the trails this spring and summer, remember to track wild wonder with great awe, but also great caution.

References and Resources
Reptiles of Arizona
Live Science - Gopher Snake Facts
Sciencing - How to Identify Baby Rattlesnakes

Images: Emily Richardson and Sharon Pegany

Cultivate Wonder... Discover Design

Wake Up Sleepheads!

Desert spring is in the air.  Bird and insect sounds are louder. Plants are showing off their new tender spring green growth, and each morning, there is definitely a soothing warmth chasing the night chill away. Yet in the desert, there is one tell tale sign that signals the coming of spring more than any other... the appearance of reptiles. These cold-blooded creatures have been hibernating through the cooler months and a series of warm days will cause them to begin to stir. It's their time.

The first reptiles to appear are the small lizards.  Due to their size, their body temperature warms and cools more rapidly, so they can warm up and get moving easier than the big guys. This week, we noticed a marked increase in small lizards lounging on the sun-warmed rocks who skitter away at the slightest intrusion.

Hibernation is one of those perplexing design mysteries found in the natural world.  Why do some creatures have the ability to slip into an efficient energy saving mode for several months when others have to store food caches, migrate or find some other crafty way to tough it out when food supplies dwindle? 

In the case of lizards and other "cold-blooded" or ectothermic* creatures, their bodies are dependent on the outside temperature to regulate internal temperature and fuel their metabolism. Instead of getting most of their energy from the food they eat like mammals do, cold blooded animals are energized by the warmth of the sun.  Their muscles are triggered by a chemical reaction that is fast in warm weather and slower in cold weather. Cold blooded, or ectothermic animals are usually elongated or flat in design, allowing heat to be exchanged with the surrounding environment more efficiently. 

The chemical process design in ectothermic animals is fascinating. At the cellular level, water around each cell can freeze, but due to a flow of glucose into the cell, the fluid inside the cell does not freeze, almost like it has been injected with a natural anti-freeze! Animals like frogs can hibernate at temperatures below freezing and still survive. 

The next time you see a lizard lounging in the sun, remember that this well-designed creature is not interested in sporting a tan, but rather in getting an energy boost! Observe his sleek elongated body which can be quickly warmed through by the heat of the rock underneath and the sun overhead. Brilliant design! 

Ectothermic  - Of or relating to an organism that regulates its body temperature largely by exchanging heat with its surrounding environment.  dictionary.com

References and Resources
Arizona-Sonora Museum - Diurnal or Nocturnal Hide and Seek
BBC Nature Wildlife - Hibernation 
American Chemical Society - How Animals Survive Temperature Extremes

Image: Sharon Pegany