How Does the Saguaro Cactus Work?

This cactus is a source of food and construction material for people and animals alike, especially during the dry season in the Sonaran Desert. Learn more about it in this episode of BrainStuff, based on this article: https://science.howstuffworks.com/life/botany/saguaro-cactus.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeartRadio. Hey brain Stuff,
Lauren Vogelbaum. Here. If you were to grab the nearest
piece of paper and draw a cactus, think not something
you might have in your house, but a wild desert cactus.
Chances are decent that the first thing that would come

(00:22):
to mind would be a tall, cylindrical cactus with a
couple arms sticking out from the sides with bent elbows
pointing upward. This is the sowarrow cactus, and it's the
only cactus on the planet that looks like that. In
spite of its iconic silhouette made popular in Hollywood, Western
films and Looney Tunes, of most people have never seen

(00:44):
one in real life, as it only grows in a
small area of the American Southwest and northern Mexico. Suarrows
are the tallest North American cacti, native to and common
throughout the Sonoran Desert in the southwestern corner of the
United States and northwestern Mexico. Or they can be the tallest,

(01:05):
they grow very slowly. At the age of ten years
a soorrow might still be less than two inches high
that's less than five centimeters, but over their entire lifespan,
which can be over one hundred and fifty years. They
can grow as much as forty to sixty feet tall
that's twelve to eighteen meters. They don't always grow their

(01:26):
iconic arms, but they can grow over twenty five of them,
and when they're fully hydrated and thriving, they can weigh
over thirty two hundred pounds that's fifteen hundred kilos. Because
of their size, soarrows are important to the local ecosystem
as they provide food and shelter for various desert animals,

(01:48):
and because they're often the tallest thing standing in the
desert landscape, they can fill the niche that's usually occupied
by trees. They are the desert go to for nesting
and perching birds and protection for other animals, and once
a sorrow has died and fallen, its decomposing body provides
important organic matter to the desert ecosystem. A sowarro cacti

(02:12):
have also been an important natural resource for the indigenous
peoples of the Sonoran Desert before the article. This episode
is based on How Stuffworks. Spoke by email with Kat Rumbley,
marketing and media manager at the Arizona Sonora Desert Museum
in Tucson, Arizona. She said, the tohono o Odam Seri

(02:32):
and other local peoples have used sowaro as a food
plant and used sowaro ribs as construction material. Many members
of the tohono Ohodam nation still harvest toarrow fruit to
this day, as the harvest marks their new year and
provides them with sowarro syrup for the year to come.
In the cultural traditions of the tahono Ohodam, the soarros

(02:53):
are considered people the ancestors of today's tahono Ohodam. While
some other cacties spread by vegetative reproduction essentially cloning. A
soarows reproduced by seed which they grow in stout pretty
cone shaped flowers that are white with a creamy yellow center.

(03:13):
It's the state flower of Arizona, and they require a
pollinator to get those flowers pollen from plant to plant.
A Rumbley explained, flowers of the sowarrow are pollinated by
the Lesser long nosed bat and the Mexican long tongued
bat at night, and by bees and birds such as
the white winged dove during the day. Soorrow fruits develop

(03:36):
right before summer monsoon rainfall and serve as a critical
food and moisture source for animals after the famine period
of dry early summer. Those fruits are green on the
outside as they develop, and can blush pinkish when they mature,
and many split open in a way that honestly looks
a little like a demigorgon from Stranger Things, but instead

(03:59):
of a gaping mall of teeth, they have bright red
flesh and many small black seeds. The fruit is very
sweet and can be eaten raw or processed into jams, syrups,
fruit leather, wine, or non alcoholic drinks. The seeds are
nutty and can be eaten raw or dried, and ground
and flour, which can be used in baked goods like cookies, crackers,

(04:21):
or flatbreads, or to make a tasty porridge. If the
fruits aren't harvested when the heavy monsoon rains come in
midsummer in early autumn, they're knocked from the tops of
the plant to the base and can be carried by
floods to be established in new spots. Their seeds are
also spread by animals that eat their fruits, and perhaps

(04:41):
especially ants which berry a surplus of sowarrow seeds in
their nests for their larvae to eat. Rumbly said, the
conditions for successful sowarrow seed germination are relatively specific, so
you'll notice large cohorts of cacti that are all the
same age due to establishment in u years. With these
specific conditions, saros have a pretty broad geographic range for

(05:07):
a plant that's so specifically designed for one ecosystem, but
cold is their kryptonite. They avoid both the cold air
drainage basins in the lowest areas of the Snaran Desert
as well as any elevations high enough to have much frost. Therefore,
soarrows keep to the warm air belts in the foothills
at the base of desert mountains within their range. The

(05:31):
sowarro currently faces threats such as wildfires, increased summer temperatures,
and inconsistent rainfall due to climate change, as well as
loss of habitat due to livestock, invasive species, and people
building a bunch of stuff. Rumbley said development and increased
urbanization within its habitat removes mature plants, eliminates the favorable

(05:54):
areas for suarrows to establish, and influences climate change by
producing urban heat eyeland that become inhospitable to soarows. A
mature soorrow can produce about a million seeds every year,
but even under good conditions, only a few will survive
to become mature cacti themselves. Changes in rainfall patterns affect

(06:17):
the establishment of young soarrows, as the younglings need dependable
watering and they suffer under constant record breaking high temperatures.
And the introduction of grazing to desert landscapes has reduced
nurse plant cover and is thought to be negatively affecting
sowarrow establishment. A rumbly said human introduced invasives such as

(06:40):
buffal grass, create fodder for wildfires that would not traditionally
be able to spread in the sparse desert landscape. The
soarrows are ill adapted to fire, as are many desert
endemic species, and are not able to recover from significant
burn events. A cattle ranchers first brought buffalo grass to
the area in the nineteen thirties, hoping to feed their

(07:03):
herds and control erosion. Buffalgrass is now considered invasive. It
can double an abundance in as little as three years.
Removal efforts have been ongoing since nineteen ninety and a
number of measures have proven successful without harming other local wildlife.
To learn more, including how you can help, check out

(07:24):
friendsofsowaro dot org. That's Friends of sag Uaro dot org.
They're not a sponsor, we just think they're pretty cool.
Today's episode is based on the article the Souaro cactus
is an iconic symbol of the Americansouthwest on how Stuffworks

(07:45):
dot com, written by Jesslynshields. The brain Stuff is production
of iHeartRadio in partnership with how stuffworks dot com and
is produced by Tyler Klang. Four more podcasts from my
Heart Radio, visit the Aheartradio app, Apple Podcasts, or wherever
you listen to your favorite shows.