Sonoran Desert
The Sonoran Desert, in which Tucson finds itself, is an arid region
but is lush in comparison to most other deserts. It encompasses a
rich spectrum of some 2,000 species of plants and thousands of desert
animal species.
Tucson is in the northeastern section of the Sonora desert,
called the Arizona Upland. It is the highest and coldest subdivision of
the Sonoran desert. Trees are common on rocky slopes and saguaros
are found everywhere but on the valley floors. This community is also
called the saguaro-palo verde forest.
Seasons in the Sonora Desert
Sonoran Desert Animals and Wildlife
Sonoran Desert Plants and Wildflowers
The amount and seasonality of rainfall are defining characteristics of the Sonoran Desert. Residents who move to Tucson from temperate climates often complain about the lack of seasons. Actually Arizona Upland has five seasons, which, though more subtle than Spring/Summer/Fall/Winter, are distinct.
Summer monsoon or summer rainy season (early July to mid-
September): The year traditionally begins with the often abrupt
arrival of the summer rains – the monsoons. A tropical air mass
adds humidity and "cools" June's extreme temperatures. Spectacular
lightening storms and deafening thunder rumbles across Tucson, followed
by a downpour resulting in filled arroyos and perhaps rumbling "rivers".
How to protect yourself during a monsoon:
- To avoid being struck by lightening, do not stand near trees or tall poles. Stay in your home or vehicle if possible.
- Avoid areas that are prone to flooding. The rains come swiftly and heavily.
- Do not use a telephone.
- Avoid large farm equipment, golf carts or other large metal equipment.
- Dust devils are also associated with monsoons. Try to avoid getting caught in one.
- Visibility can be near zero when monsoon thunderstorms are raging. If driving in a dangerous storm, find somewhere to safely park your car.
- If you pull over in your car to the side of the road, do not leave your lights on. Drivers with little or no visibility behind you may think you are still on the road and follow you. Smack!
- Arizona does not really get tornadoes. You might see a microburst now and then. They, too, are scary.
- If you are outside hiking or camping, be aware of quick wind shifts, quick cooling of temperature and increasing wind velocity. These are signals for thunderstorm activity.
- If you are on a boat, get to land.
- Do not huddle closely together with other people. Spread out.
- Avoid wide open areas.
- If your hair starts to stand on end, that is a sign of electricity and you may be about to be struck by lightening. Drop to your knees and cover your head.
Autumn (October and November): Characterized by warm
temperatures, low humidity and little rain. In years with adequate
rain, winter annuals begin their growth season, but few flowers are in
bloom. Autumn and late summer occasionally receive heavy rains.
Winter (December, January and February]: Potentially, an
occasional dusting of snow and just a few mornings with freezing
temperatures, but usually sunny, mild days, with intermittent storms
with wind, rain, and cool to cold temperatures; February often warm and
dry, more spring-like.
Spring (From early / late February through April): Exemplified by
mild temperatures, little rain, and often windy. This is the main
flowering season for annuals, shrubs and trees; winter annuals may
bloom in February in warm, wet years.
Foresummer drought (May and June): This is the season of high
temperatures and very low humidity and no rain most years. May is very
warm and often windy; June is hot and usually calm. There is little
biological activity except for the flowering and fruiting of saguaro,
foothill palo verdes, and desert ironwood trees. Flora and fauna are in
basic survival mode until the rains arrive.
| Jan |
Feb |
Mar |
Apr |
May |
June |
July |
Aug |
Sept |
Oct |
Nov |
Dec | |
| High -0F | 65.8 | 69.1 | 69.1 | 75.0 | 92.1 | 100. | 101. | 98.7 | 95.4 | 96.2 | 74.0 | 65.3 |
| Low - 0F |
40.9 | 43.8 | 47.6 | 53.5 | 61.6 | 70.1 | 74.7 | 73.6 | 68.7 | 57.9 | 46.5 | 40.5 |
| Avg - 0F |
53.4 | 56.5 | 61.3 | 68.3 | 76.9 | 85.4 | 87.9 | 86.2 | 68.7 | 72.0 | 60.3 | 52.9 |
| Rain | 1.1 | 1.26 | 1.02 | 0.33 | 0.27 | 0.28 | 2.03 | 3.02 | 1.41 | 1.12 | .82 | 1.44 |
It is a miracle that life can survive in the extreme conditions of the desert. Fortunately, most desert animals have evolved both behavioral and physiological mechanisms to solve the heat and water problems the desert environment creates. Among the thousands of desert animal species, there are almost as many remarkable behavioral and structural adaptations developed for avoiding excess heat.
Be prepared to encounter the following desert inhabitants.
Desert Cottontails are named after their tail, which is shaped like a
cottony ball. The desert portion of their common name arises from their
distribution across the arid lands of the American Southwest and Plains
states. The adult desert cottontail is light colored, tan to
gray, with a yellowish tinge. The tail is rounded and looks like a
cottonball. The cottontail is thirteen to seventeen inches and
the average weight is two to three pounds. Females are larger than the
males.
Cottontails are active early morning, late afternoon and at night, but
may be seen at any time of the day. During the day, cottontails may
rest in the shades of large shrubs, in burrows or within thickets. In
the hot months of summer, they conserve moisture and energy by avoiding
activity during the hot, dry daylight hours. They eat a wide
variety of plants, including grasses, shrubs and even cacti; however,
ninety percent of their diet is grass. Cottontails will forage on
domestic crops, even the bark of fruit trees.
When alarmed, a cottontail can run up to twenty miles per hour in a
zigzag pattern to escape predators. Often, the cottontail runs to a
protective location like a burrow or thicket. If cornered by a small
predator, a cottontail may "bowl over" the predator and give it a kick
with its powerful hind legs as well. A cottontail may also freeze when
danger lurks, and scrunch down to blend into its surroundings.
Cottontails are preyed upon by a number of predators, including golden
and bald eagles, great horned owls, hawks, badgers, coyotes, foxes,
bobcats and humans. Rattlesnakes may prey on the young.
The Coyote is found throughout North America from eastern Alaska to New England and south through Mexico to Panama. The coyote is a member of the dog family. In size and shape the coyote is similar to a Collie, but it's tail is round and bushy and is carried straight out below the level of its back. Coyotes found in low deserts and valleys weigh about 20 pounds, less than half of their mountain kin, who can weigh up to 50 pounds. Desert coyotes are light gray or tan with a black tip on the tail.
The coyote is one of the few wild animals whose vocalizations are
frequently heard. At night, coyotes both howl (a high quavering cry)
and emit a series of short, high-pitched yips. The howl is used to keep
in touch with other coyotes in the area. Yelping is often heard in play
among pups.
Their typical diet consists of small mammals, insects, reptiles and
fruit. Typically hunting for food alone, they will band together
in the hunt for larger prey. Coyotes live in dens usually hidden from
view. They are evasive and coupled with a good sense of smell,
vision and hearing, they survive in the wild and in more urban settings.
The Javelina, or Collared Peccary, is the only wild, native,
pig-looking animal found in the United States. They are called Javelina
because of their razor-sharp tusks, Spanish for javelin or spear.
Although they look similar to pigs, Peccaries are classified in a
family of their own because of anatomical differences. Pecca
ries are
more slender and 30-50 pounds smaller than pigs, have longer, thinner
legs and smaller hooves. Peccaries have large heads and long snouts
with thick coats of dark-gray, bristly hair and a band of white hair
(collar) around the neck. A mane of long, stiff hairs runs down the
back from head to rump. The Peccary is colored a grizzled black and
gray overall with a dark dorsal stripe but is lighter around the
shoulders. The fur is very coarse. The adult male Collared Peccary is
46 to 60 inches in length and is usually 20 to 24 inches in height. The
adult male weighs between 40 and 60 pounds. You may smell a Peccary
before you see it. Peccaries have a powerful musk gland on the top of
the rump. Their odor is always apparent, especially when they are
excited.
Peccaries usually travel in a band from 6 to 12 although as many as 50
have been seen together. They are most active during early morning and
evening when it is cooler. Their diet consists of roots, fruits,
insects, worms, and reptiles. The prickly pear is ideal food for the
Collared Peccary due to its high water content. Collared Peccary have
poor eyesight and good hearing. Peccaries are not dangerous when left
alone but an entire band can attack if one is wounded or pursued.
Speedy and agile, they can drive off dogs, Coyotes and Bobcats.
Bobcats are found primarily in mountains and even in desert areas where
water is available, favoring rocky, brushy hillsides on which to live
and hunt. The name Bobcat may have originated from its short tail,
which is only 6 or 7 inches long. The Bobcat has long legs and
large paws. Typically weighing 15 to 20 pounds, large specimens can
weigh up to 30 pounds.
Despite its pussycat appearance when seen in repose, the Bobcat is
quite fierce and is equipped to kill animals as large as deer.
Typically, Bobcats subsist on a diet of rabbits, ground squirrels,
mice, pocket gophers and wood rats. Quail have also been found in
bobcat stomachs. The Bobcat roams freely at night.
Because Bobcats are solitary animals, males and females spend only a
few days of the year together -- during courtship and mating. Bobcats
in captivity have been known to live as long as 25 years.
Gambel's Quail are pear-shaped birds with short legs and roundish
wings. Both sexes are gray above and buff below, with white-streaked
russet sides. Males have a black throat and face and a head plume
(called a "topknot"), a red cap and white headband. Females have a less
prominent plume and lack black coloration and red head cap. The birds
have a 14-inch wing span and average weight of six ounces.
They eat seeds of grasses, shrubs, trees and cacti as well as
herbaceous material, fruits and berries. They are ground feeders,
generally seeking food in the morning and afternoon. They obtain water
from food material, but they may also require some free water.
These gregarious birds often join together in groups known as coveys,
which may total 20 or more individuals in fall and winter. Their
call, "ka-KAA-ka-ka," is used to locate a mate or other covey members,
issuing the call most often in midmorning or late afternoon. When
alarmed, they emit a distinct "chip-chip-chip". Natural predators
include bobcats, hawks, king snakes and coachwhips. When alarmed,
quail commonly sprint into dense undergrowth rather than taking flight.
The legendary Roadrunner, popularized in Warner Bros cartoons for
sprinting across film reel deserts, is recognized by its distinctive
features and for its ability to capture and eat rattlesnakes.
Ranging in length from 20 to 24 inches, it is a black and white mottled
ground bird with a prominent head crest and oversized bill.
When the Roadrunner senses danger or is traveling downhill, it flies,
revealing short, rounded wings with a white crescent. But it cannot
keep its large body airborne for more than a few seconds, and so
prefers walking or running (up to 17 miles per hour) usually with a
clownish gait.
The Roadrunner is uniquely suited to a desert environment by a number
of physiological and behavioral adaptations, including: carnivorous
habits which offer it a large supply of very moist food; reduction of
its activity 50% during the heat of midday; and its extreme quickness
which allows it to snatch a humming bird or dragonfly from midair. The
Roadrunner feeds almost exclusively on other animals, including
insects, scorpions, lizards, snakes – including rattlesnakes, rodents
and other birds. Up to 10 % of its winter diet may consist of plant
material due to the scarcity of desert animals at that time of the year.
The Roadrunner inhabits open, flat or rolling terrain with scattered
cover of dry brush, chaparral or other desert scrub. In the
Sonoran Deserts of Arizona, Roadrunners nest in Spring then again in
August or September after summer rains increase their food sources.
Gila Monsters are one of only two species of venomous lizards and is
the largest lizard known to the United States. They can be located
under rocks, under shrubs in gravelly and sandy soils, and in borrows
they've dug themselves or borrowed from other animals. The Gila Monster
is a stout-bodied lizard that grows 18 to 24 inches in length and
typically weighs three to five pounds. It has bead-like black,
orange, pink or yellow broken blotches, bars and spots, with bands
extending onto its blunt tail. Its face is black, and it has small,
bead-like scales across its back. It is named for the Gila River Basin
of the southwestern United States.
During warm weather the Gila Monster feeds at night on small mammals,
birds and eggs. Fat stored in the tail and abdomen during this period
is utilized during hibernation in the winter months.
They are not as quick as other lizards, but they have a strong,
tenacious bite. Most of the Gila Monster's teeth have two grooves
that conduct the venom, a nerve toxin, from glands in the lower jaw.
The toxin is not injected like that of the snake, but flows into the
wound as the lizard chews on its victim. While the bite can overpower
predators and prey, it is rarely fatal to humans.
The Western Diamondback Rattlesnake has such a hold on the human psyche
that it has been a symbol of the American Southwest from prehistoric
into historic times. It figures in ancient mythology, ceramics and rock
art and in modern story and media.
The Western Diamondback, which can exceed seven feet in length, is the
king of our twenty odd species and sub-species of Southwestern desert
rattlers, not only in terms of size, but also in terms of its fearsome
reputation. " It's basic color ranges from brown to gray to pinkish,
depending on the shade of its habitat. Its back is lined with dark
diamond-shaped blotches outlined by lighter-colored scales. Its head is
distinguished by two dark stripes, one on each side of its face, which
run diagonally, like Zorro's mask, from its eyes back to its jaws. Its
tail is circled by several alternating black and white bands, like the
pattern of a raccoon's tail. Its patterns are most distinctive when the
snake is young and are more faded, blurred and camouflaged when it is
older.
The Western Diamondback has a spade-shaped head, a fiendish fang and
venom system, elliptical pupils and heat-sensing facial pits. The venom
causes extensive tissue damage, bleeding and swelling in humans. The
facial pits guide the snake swiftly and surely to warm blooded prey
such as rodents, even in the total darkness of the animals' burrows.
Its rattles – a distinguishing feature it shares only with other
rattlesnakes – grows segment by segment, each rattle the keratin
remnant of a shed skin. It can add two or three rattles each year, with
each molt, although it may also break off some of its rattles in the
course of a year. The Western Diamondback coils, rattles, and stands
its ground when threatened. It hunts from late evening to early
morning, crawling either sinuously like other snakes or rectilinearly
like a caterpillar.
The Western Diamondback seeks to live among communities of small
mammals such as prairie dogs, rabbits, mice and rats. Usually hunting
at night, it ambushes victims or attacks them in their burrows,
sometimes striking and devouring an animal weighing more than the
snake. The snake will also eat birds. Once fed, the snake can go
several weeks before feeding again. The Western Diamondback has
predators. It may become a meal for an eagle, a hawk, or a roadrunner;
for a kingsnake; or for a coyote. Regarded as an enemy and a threat, it
may be trampled to death by a deer, an antelope, a cow, a horse or even
a sheep.
Western Diamondbacks spend the colder months hibernating in dens. They emerge in spring, sexually driven, hungry and mean.
Fact or Fiction?
1. The Western Diamondback always rattles to warn a victim.
2. It can grow to be ten or even twelve feet long.
3. It swallows its young to protect them from harm.
4. Its venom, flesh, skin or rattles can cure various human diseases and wounds.
5. Its age corresponds to the number of its rattles.
(all Fiction)
The Bull Snake, or Gopher Snake, is a hissing constrictor often
mistaken as a Rattlesnake. Bull Snakes are up to about 5 feet (1.5 m)
long. They range from yellow-brown to brown to cream-colored, with
black and brown markings; the belly is light brown. This snake has a
small head and a large nose shield, which it uses to dig. Like all
snakes, Bull Snakes are cold-blooded; they are the same temperature as
the environment. The Bull Snake smells using its tongue. This snake has
teeth and can bite (but it is not venomous). They are carnivores and
like all snakes, they swallow the prey whole, head first. The snake's
top and bottom jaws are attached to each other with stretchy ligaments,
which let the snake swallow animals that are wider than itself. Snakes
don't chew their food; they digest it with very strong acids in the
snake's stomach. Bull Snakes eat burrowing mammals (like mice, rabbits,
gophers, and ground squirrels), ground-nesting birds, and bird eggs.
After eating a large animal, the Bull Snake needs no food for a long
time, and it rests for weeks. Enemies of the Bull Snake include hawks
and eagles or coyotes. Alerted to danger, the snake coils up,
vibrates its tail and hisses a warning. "The Gopher snake can also
spread and flatten its head, thereby resembling a rattler even more. An
unsure predator mistakes this behavior and the somewhat triangular head
of the Gopher snake for a rattlesnake and backs off from its pursuit."
The Bull Snake lives in North America, in sandy areas, prairies, open forests (pine and oak), agricultural fields, and brush.
You can find more information about these and other wildlife common to
the Sonoran Desert by accessing this web link.
http://www.desertusa.com/animal.html
Contrary to popular opinion, the Sonoran Desert is not brown and
barren. Instead, its landscapes are adorned with explosions of
spring wildflowers and succulent cactus. Desert plants have adapted to
the extremes of heat and aridity by using both physical and behavioral
mechanisms, much like desert animals.
If conditions are right, the best time to visit Tucson is during spring
- the prime desert wildflower season. However, it is worth visiting at
other times of the year. High in the hills there are summer wildflowers
and fall color. Late summer brings thunderstorms. "Nothing is more
spectacular than driving out to the West Unit of Saguaro National Park
during an afternoon thunderstorm to photograph the dark clouds and
lightning bolts in the west with saguaro cactus in the foreground. "
The best time for spring wildflowers is March through May. Each plant,
though, has its own time. March has the most variety with penstemon,
brittlebush, fairy duster and desert marigold in bloom. The giant
saguaro cacti start blooming in early May and run through early June.
However, you must be lucky and early to catch the saguaro bloom. The
flowers open at night and close by noon the next day, and that is the
end of it. The ocotillo, a spiny plant, has red blossoms in April.
These blossoms also attract hummingbirds. The Palo Verde, a green-bark
tree, blooms in April and May. Prickly pear cactus put forth their
showy flowers around late April. The desert canyons are carpeted with
lavender ironwood in late May.
For more information on Sonoran Desert plants and wildflowers, and to
view the Wildflower Field Guide, visit the following web link:
http://www.desertusa.com/flora.html
