The Saguaro National Park was made a national monument in 1933. In Nov of 1961, President Kennedy signed a bill expanding the monument to include Tucson Mountain Park. Then on 14 Oct 1994, Saguaro National Park was established.
Saguaro National Monument - 1933
Tucson Mountain District - 1961
Saguaro Wilderness Area 71,400 acres - 1975
National Park Status - 1994
Size and Visitation
Gross Area Acres - 91,446
Total Recreation Visits in 2000 - 757,417
Saguaro National Park is open year round, daily from sunrise to sunset, with peak visitation in March.
The saguaro has been described as the monarch of the Sonoran Desert, as a prickly horror, as the supreme symbol of the American Southwest, and as a plant with personality. It is renowned for the variety of odd, all too human shapes it assumes, shapes that inspire wild and fanciful imaginings. Giant saguaro cacti, unique to the Sonoran Desert, sometimes reach a height of 50 feet in this cactus forest, which covers the valley floor, rising into the Rincon and West Tucson mountains.
Since 1933 this extraordinary giant cactus has been protected within Saguaro National Park. Preserved along with it are many other members of the Sonoran Desert community, other cacti, desert trees and shrubs, and animals. In lushness and variety of life the Sonoran Desert far surpasses all other North American deserts and yet paradoxically, it is one of the hottest and driest regions on the continent. Summer midday temperatures commonly climb above 100 degrees F. Less than 12 inches of rain fall in a typical year. Between summer and winter rainy seasons, it is not unusual for months to pass without a drop of rain. The plants and animals able to survive this environment, with adaptations specially designed for desert survival, make up one of the most interesting and unusual collections of life in the United States.
The life force is patient here. Desert vegetation, of times appearing to have succumbed to a harsh and unforgiving environment, lies dormant, anxiously awaiting the rainfall and mild weather that will trigger its growth, painting a profusion of colors. At the edges of daylight and under clear night stars is a fascinating multitude of generally familiar desert wildlife. Waiting out day time heat, these animals run, hop, crawl, and burrow in the slow rhythm of desert life. Under bright sun and blue sky, when the night creatures have long since sought shelter, bighorn sheep and golden eagles add an air of unfettered majesty to this land.
The desert. Some think it wretched and seemingly useless. For all its harshness, the desert is a land of surprising variety and complexity, a land of extreme fragility. Today's moment of carelessness may leave lasting scars or disrupt an intricate system of life that hints at its hidden vitality. To the close observer, however, a tiny flower bud or a lizards frantic dash reveals Joshua Tree as a place of beauty and life. Take your time as you travel through this area. Joshua Tree National park provides space for finding freedom from everyday routines for self- discovery, and a refuge for the human spirit. Let the desert take hold of you.
Deserts are composed of plants and animals living together in what seems like an oppressive environment. Living and nonliving elements interact complexly, forming the desert ecosystem. The lifeblood, of course, is the sun's energy, converted to a living form by green plants.
Unlike most ecosystems, in which plants complete for space in the sun, the desert's sparsity is created in part by too much solar energy. Plants use one of two life strategies to survive. Annuals avoid the extremes, compress their life cycle, and exist while the environment is favorable. Sudden carpets of spring wildflowers are displays of awakened dormancy as seeds, like time travelers, revive to spout flower, and renew their kind. The alternate strategy is that of the patient perennial. Conservative year-round residents like the Joshua tree flourish during the moist periods and bide their time during long droughts.
Many animals derive their energy from plants, but desert plants give up the fruits of their production only reluctantly. Sharp spines and chemical-laden leaves complicate the lives of plant-eaters. The kangaroo rat avoids these obstacles by eating seeds. While safe to eat, seeds can be hard to find. Many are small, looking surprising like the sand grains that offer them sanctuary. These kangaroo rats uses sensitive front paws to sift through the sand, discovering seeds by smell as well as by touch. Seeds consumed by the kangaroo rat are converted into animal tissue.
Energy continues to flow through the web as kangaroo rats and other plant-eaters, such as jackrabbits, fall prey to meat-eaters. It takes many rabbits and rodents to feed a single owl, coyote, bobcat, or eagle, so there must be far more prey than predators. The original solar energy converted to plant tissue has now been transformed several times as it moves through the food web.
Desert animals are well adapted to life in their demanding environment. Many avoid the heat by day by venturing out only at night. These nocturnal animals include the cactus mouse and western diamondback rattlesnake. Other creatures restrict their activities to cooler morning and evening hours. Gambel's quail, roadrunners, and other birds feed at these times, as do many reptiles, including the desert tortoise and Gila monsters. Animals who are out at midday have special adaptations for dissipating the heat. One animal, the jackrabbit, radiates heat from its oversized ears. Desert creatures also have ways of dealing with acute shortages of water. During droughts, javelinas eat succulent prickly pear pads. The kangaroo rat never needs to drink a drop of water, getting all it needs from the seeds it eats.
As the original source of living energy, plants fulfill a vital role in the food web. A large productive plant such as the Saguaro cactus resembles a focal point for a complex community of wildlife. Some birds nest in the living tree. Others come regularly to feed on resident insects. Discarded limbs or the toppled body of the cactus provide homes for the night lizard and termites. Even in death, the plant energy of the Joshua tree is converted by termites to animal energy. Termites find protection from heat, cold, and drying winds in the decaying fiber. The night lizard finds the same environmental sanctuary along with its preference for food, termites. Energy continues to flow in the web as an owl or snake feeds on an unwary night lizard. As the Saguaro cactus continues to decompose, stink-bugs may nibble on the fiber, helping termites consume their home. Eventually all the plant's nutrients and energy have been transformed into another living form or released into the soil for use by other plants. The web is fragile, no stronger than its weakest link, yet it endures.
The desert is immense and infinitely variable, yet delicate and fragile. It is a land shaped by sudden torrents of rain and climatic extremes. Rainfall is sparse and unpredictable. Streambeds are usually dry and water holes are few. This land may appear lifeless, but within its parched environment are intricate living systems, each fragment performing a slightly different function and each fragment depending upon the whole system for survival.
For centuries peoples of the Sonora Desert have used natural products of the saguaro. In the summer the saguaro provided a nourishing bounty of juicy fig-like fruits. Native Tohono O�Odham Indians harvested them by knocking them off the tall cacti with long poles. From the fresh fruit the Tohono O�Odham made jam, syrup, and for their religious ceremonies, wine. So important was the fruit to the Tohono O�Odham that the season of its harvest marked the beginning of their new year. The saguaro also provided seeds for the Tohono O�Odhams and their chickens to eat, and strong woody ribs, which the plant uses to support its huge weight, to build shelters and fences.
The flowers of the saguaro, big, bold and numerous, bloom and color the desert in late April, May and June. Each blossom opens in the cool of the night a few hours after sunset. By the next afternoon, the flower has wilted, and the brief period of bloom ended. The spectacle repeats itself night after night for about four week until as many as one hundred flowers have appeared on each saguaro. In the few hours the flowers are open a variety of flying animals will have succeeded in pollinating many of them. Whitewinged doves, and long-nosed bats, summer migrants from Mexico, honeybees, and moths accidentally become powdered with sticky pollen as they feed on the sweet nectar inside the flower. As they travel from flower to flower, they transport the pollen, fertilizing as they go.
In June and July the fruit of the saguaro ripens. The sugary pulp of each fruit contains as many as 2,000 seeds. Javelinas, coyotes, foxes, squirrels and other rodents, harvester ants, and many birds feed on the fruit and seeds.
Many features assist the saguaro in storing and conserving that most precious of desert commodities, water. Accordion-like pleats allow the saguaro to expand and hold water collected through the roots. Spongy flesh in the trunk and branches serves as a reservoir where water is stored as a slow to evaporate gelatin like substance. Unlike most plants, the saguaro cactus has no conventional leaves, which transpire large amounts of water. The food-making process of photosynthesis normally carried out by green leaves is performed in the trunk and branches. Spines discourage animals from taking the cactus' moisture, shade the plant, and shield it from drying winds. Waxy skin aids in reducing moisture loss.
The saguaro collects water with a network of roots that lies about 3 inches below the surface and stretches as far out from the main stem as the saguaro is tall. In a single rainfall, these shallow roots, along with special small root hairs that grow in response to moisture, may soak up as much as 200 gallons of water, enough to last the saguaro a year.
Honeybees also inhabit some of the disguarded holes of the Saguaro Cactus. For residents, the holes are a retreat from desert temperature extremes. Well insulated by thick walls, the holes are as much as 20 degrees cooler in summer and 20 degrees warmer in the winter. Other saguaro dwellers live in bulky nest. These include the redtailed hawk and Harris hawk.
Plants of Saguaro
A variety of plants live in the Sonora Desert with the saguaro. There are more than 50 types of cacti, including:
Birds of Saguaro
The saguaro is like a multi-storied complex; many animals live in close quarters and the occupants change constantly. Two common residents are the Gila woodpecker and glided flicker. These birds dwell in nest holes they make in the trunk and larger branches of saguaros. The birds excavate new holes each spring and reject several cavities in one nesting season before settling in one and raising a family. Their industriousness leaves many holes for other animals, who rapidly move in. The birds who compete for the homes include:
Phainopeplas elf owls
The life of the saguaro is a struggle from the beginning. The saguaro begins its life as a shiny black seed no bigger that a pinhead. What it lacks in size, it more than makes up for in numbers. One saguaro produces tens of thousands of seeds in a year, and as many as 40 million in a life time of 175 - 200 years. From the start, the odds against survival are great. Out of all the seeds that saguaro produces in its new life, few will survive to adulthood.
Seeds and young saguaros have the best chance for survival if they are cared for by nurse trees such as palo verde and mesquite. Saguaro seedlings that grow under these sheltering plants are shaded from the desert's intense sunlight, blanketed from winter cold, hidden from rodents, birds and other animals that eat them. Rocks provide similar protection for the young saguaros. Saguaros do best on bajadas, gently sloping outwash plains at the foot of desert mountains.
A saguaro's growth is extremely slow. Growth occurs in spurts, with most of it taking place in the summer rainy season each year. By the end of a year, the saguaro seedling may measure only 1/4 inch. After 15 years, the saguaro may be barely a foot tall. At about 30 years saguaro can begin to flower and produce fruits. By 50 years, the saguaro may be as tall as 7 feet. After about 75 years, it may sprout its first branches or "arms." The branches begin as prickly balls, then extend out and upward.
By 100 years the saguaro may have reached 25 feet. Saguaros that live 150 years or more attain the grandest size, towering as much as 50 feet and weighing 8 tons, sometimes more, dwarfing every other living thing in the desert. These are the largest cacti in the United States. Their huge bulk is supported by a strong but flexible cylinder-shaped framework of long woody ribs.
Saguaros may die of old age, but they also die of other causes. Animals eat the seeds and seedlings, lightning and winds kill large saguaro, and severe droughts weaken and kill all ages. The saguaro is vulnerable during every stage of its life.
Where there is a balance of life and death, saguaro forests thrive. Until recent years, in some forests in the park deaths have greatly outnumbered the growth of new young saguaro. Biologists believe freezes are the park's major cause of saguaro deaths. The saguaros here are at their extreme northern and eastern range, where the coldest winter temperatures most often occur. Humans, too have played a part in the decline. Livestock grazing, which continued from the 1880's until 1979, devastated some cactus forests. Seedlings were killed outright by trampling or were tramping or were unable to find suitable places to grow because the ground had been compacted and nurse plants killed.
Today, with grazing eliminated, recovery of the saguaro is underway in several areas. Thousands of young saguaros have taken hold, and they are thriving. Still natural forces, vandalism, and cactus rustling, the theft of saguaros for use in landscaping, continue to take a toll on the park's saguaro forests.
Information provided by the National Park Service
Activities & Calendar
Address & Phone
Annuals Blooming Season
Birds in Saguaro
Brochures, Maps, Written Info
Cacti Blooming Season
Educational Field Trips
Flower Blooming Guide
Jobs, SCA, Volunteer Positions
Junior Ranger Programs
Self Guided Field Trips
Size & Visitation
Tree Blooming Season
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