Why Do Cacti Have Spines

The cactus family is known for its prickly spines, which are actually altered leaves. The kind of leaves that a maple or oak tree has are not present on cacti. But in the distant past, they might have had leaves that were at least somewhat more similar. Due to the fact that they aid the plants in surviving in hot, dry situations, those leaves eventually changed into the prickly spines we see on cactuses today.

“They could serve as a defensive strategy to prevent herbivores, or animals that consume plants, from consuming the cactus. But spines also produce shade! “Kimberlie McCue says.

“When you are covered with spines, those spines are throwing shadows on the cactus’ body as the sun moves across the sky. They are tiny umbrellas for shade.”

All cacti are native to arid regions, and some can even survive in dry climates. How do they acquire water to exist, then? Kimberlie informs us that these plants can be found close to the water.

“There will be fog coming off the ocean in the morning. Water condenses on those spines, forming tiny droplets, which then flow down the spine, to the plant’s body, to the soil, and to the roots.”

As they hold the soil in place and offer shelter to birds and other creatures, cactuses are also crucial components of their desert ecosystems. In exchange, such animals and birds assist in pollinating the cactus flowers. Cacti are a significant local source of food for people.

Cactuses are unfortunately threatened by people who illegally steal natural plants from their surroundings. According to Kimberlie McCue, being cautious when purchasing cactus plants is one method to ensure that cacti remain healthy and numerous. Before you buy, find out where the cactus came from and confirm that the vendor is being a responsible steward of these plants.

What do the spines on a cactus do?

The spines of cacti are completely changed leaves that serve as the plant’s defense against herbivores, a source of heat radiation from the stem during the day, and a reservoir for condensed water vapour during the cooler nighttime hours.

Why do cacti lack leaves in favor of spines?

Cacti have numerous adaptations that enable them to survive in arid climates; these adaptations enable the plant to efficiently gather water, store it for a long time, and conserve it (minimizing water loss from evaporation).

Cacti have thick, succulent stems with rigid walls that store water when it rains. The stems are fleshy, green, and photosynthetic. Either the stem’s inside is spongey or hollow (depending on the cactus). The water inside the cactus is prevented from evaporating by a thick, waxy layer.

Long, fibrous roots are common in cactus, and these roots take moisture from the earth. Some cacti, such as ball cacti, have smaller, more compact roots that can capture dew that falls from the cactus.

Most cacti feature scales or spines in place of leaves (which are modified leaves). These scales and spines do not evaporate their water (unlike regular leaves, which lose a lot of water). Predators (animals that would like to consume the cactus to gain food and/or water) are kept at bay by the spines. On a cactus, areoles are a circular collection of spines. An areole is where flowers bud, and it is also where new stems branch.

Why do plants in the desert have spines?

The thorny plants, like cactus, are attractive to look at but difficult to manage because most people are reluctant to admit they would enjoy having one because of the potential for intense discomfort. Cactus, agave, and mesquite are examples of desert plants that must endure in areas with little water. To live, these desert plants must contend with a variety of strange situations.

Other plants lose moisture through the pores on their leaves and stems, which they have. Therefore, in order to lock in the meager amounts of moisture they have, these desert plants must avoid those pores. As a result, these leaves lack pores and develop hard, dry spines or thorns. By not releasing any moisture at all, these thorns save water. The lower, greener portion of a leaf has the least amount of activity, assisting the plant’s survival. To protect themselves from being nibbled on, the spikes also cover the pores.

  • They are short because of a slower development mechanism.
  • Desert plants must make efficient use of their limited water supply.
  • Even still, they develop much more slowly than typical plants do.

As a result, these clever prickly bushes develop slowly while protecting themselves and preserving resources.

How do cactus spines aid in desert survival?

Being a desert plant, your goal is to prevent water reduction. As strange as it may appear, cactus spines really work to prevent water loss in cacti.

Cactus spines primarily stop cacti from losing water by decreasing air flow around the plant. Air flow is broken up by spines, which can aid in lowering evaporation. A buffer zone with air that is a little bit more humid can also be produced by the trapped air surrounding the cactus.

This is significant because plants lose a lot of water as it evaporates off their leaves.

A cactus protects itself in what way?

The protection of cacti from predators is one of the spines’ primary roles. Most animals will avoid them because of their sharp spines, but not all. The sharp spines don’t deter javelina (wild pigs), pack rats, desert tortoises, or bighorn sheep since they eat cacti.

Unexpectedly, the cactus itself receives shade from the spines of the plant. It can be difficult to believe at first that the small cactus spines provide any actual shelter from the scorching desert sun. But it is simpler to think that the spines help to protect the surface of cacti when you realize that each spine offers a modest bit of shade and then multiply that by 1,000 or more per cactus. Additionally, the spines lessen water evaporation.

The spines of some Cholla species actually have a second function; they aid in reproduction. Chollas have small barbs at the terminals of their spines that are extremely responsive to adjacent movement. As a result, the cholla’s segments “leap out” and attach themselves to anyone passing by (animal or human). Although they don’t truly “jump,” it sure feels like they do. The dislodged cholla segment will eventually take root in the soil and develop into a new Cholla when it falls to the ground from whatever was dragging it along.

What three adaptations do cacti have?

A cactus, unlike other plants, has unique adaptations in its roots, leaves, and stems that allow it to survive in hot, dry settings. Here is a summary of these adaptations:


A cactus does not have any parts that resemble leaves, if you could look at one closely. Instead, the leaves are transformed into spines, which protrude from the plant’s tiny bumps known as areoles. Consequently, the stems carry out the process of photosynthesis rather than the leaves. Additionally, the stem of a cacti is easily exposed to sunlight because they are primarily found in arid environments.

Additionally, because excessive evaporation is prevented by the spines because water is scarce in a desert. The spines also trap air, limiting airflow and obstructing evaporation. Collecting dew from the early-morning fog is another crucial job that the spines do. The gathered dew turned into liquid water and ran down to the earth below. The plant then takes this water up. Herbivores in the desert may also be enticed to consume the delicious cactus flesh. These creatures are prevented from doing so by the spines.


To swiftly absorb precipitation, cacti have shallow, broad, fibrous roots that are near to the surface. Although the desert is a dry environment, it does occasionally rain there. These plants typically have broad, shallow roots that may absorb a lot of groundwater. In addition, throughout the course of two hours during rainsoften growing, cactus roots also exhibit brief growth spurts. These fictitious roots disappear after it rains. When it rains, root hairs quickly expand to enhance the absorption surface area before dying when the ground dries out. In addition to their fibrous roots, some cacti also have a long, deep taproot that is several times longer than the plant’s height above the ground. Water that is present underground is absorbed by taproots.

Deep-layer Stomata

Stomata in cacti are located deep into the tissue as opposed to the surface. Furthermore, a photosynthetic adaptation known as Crassulacean acid metabolism causes the stomata to open at night (CAM). This drastically lowers water loss, which is crucial in a dry environment, together with the deep-layer stomata.

Thick and Expandable Stem

Cactus stems are tender. Because their stems are thicker than those of other plants, cacti may store water in their stems, specifically in collapsible water-storage cells. To hold additional water, the stems are also capable of significant expansion. They carry out photosynthesis and are green.

Short Growing Season

Continuous growth needs a lot of water, and in places like deserts, water is extremely rare. Because of this, cacti have a shorter growing season than other plants. In actuality, plants only develop for one season before ceasing growth and starting again the next year. Cacti also survive longer than other plants, although they grow considerably more slowly.

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What is required for cacti to survive?

It’s a widespread notion that cactus can survive under neglect, however this is undoubtedly untrue. A cactus need the five things listed below to survive:


In science class, we all discovered that all plants need light for photosynthesis. There must be light, regardless of the kind of plant or how much light they truly require. Cacti are the same. A cactus actually prefers sunlight because it is abundant in its native environment.

The quantity of light a cactus requires can vary depending on the species, although most cacti can live in bright, direct sunlight.

It is possible to have too much light, too. A cactus can get burnt if it is exposed to high-intensity light for an extended period of time. To prevent this problem, it is advised that you provide your cactus protection from harsh light, especially if you are trying to adapt it to a new location.

On the other hand, your cactus will grow tall and thin in quest of the light it need, a process known as etiolation, if you don’t give it enough sunshine. The plant won’t also be able to blossom because it doesn’t receive adequate sunlight exposure for photosynthesis.

So where is the ideal middle ground? Cacti like direct sunshine, but if you’re keeping yours indoors, you’ll need to expose it to full-spectrum light for 12 to 14 hours each day. Your cactus will receive all the wavelengths that sunshine offers thanks to full-spectrum light. To control the number of hours your cactus is exposed to light, you can use A Plus LED Grow Lights for Indoor Plants or this Fauna 100W COB Plant Grow Light Full Spectrum.

Here are a few quick cactus lighting suggestions to remember:

  • Pick a location for your cactus with care. Whether you keep it inside or outside, make sure it gets enough sunshine where it is.
  • To prevent shock when moving a cactus to a new location or transplanting one, gradually increase its exposure to light.
  • If your cactus lives indoors, attempt to modify the illumination according to the seasons. If you bring your cactus indoors over the winter, be sure to give it the light it requires, even if you have to reduce the quantity to reflect the season.
  • Pay close attention to how your cactus looks; if you spot a light sunburn on its surface, act quickly to offer some protection.


Your cactus needs to be in an aerated area; as obvious as this may sound, plants require air to survive. It must be kept in a well-ventilated area where it has unrestricted access to both oxygen and carbon dioxide.

Cacti breathe differently than other plants, which helps them thrive in hot, dry climates. A cactus closes its stomata during the day and opens it at night, but most plants do the opposite to prevent water loss.

A cactus can increase the air quality at night by producing more oxygen, but it isn’t a good enough excuse to cram it in a closet or other small, enclosed area. Your cactus has to be kept in an airy, open area so that it can breathe properly, especially at night.


Underwatering is one of the worst mistakes that cactus owners do. Plants believe that because cacti can survive in hot climates, they can go for weeks without water. Cacti are robust plants, but they still need frequent watering to live, just like other plants. If you don’t give them enough water, they usually die.

On the other side, some cactus owners could overwater their plants. Water that accumulates at the bottom of the container may eventually cause root rot. It is crucial to comprehend that cactus can survive periods of drought but prefer a dry environment.

How much water does a cactus thus require? The Cactus & Succulent Society of San Jose’s specialists say that cacti only require weekly watering. Make sure the soil is loose and that the pot has holes at the bottom so that any extra water can quickly drain. Water the cactus until the soil is completely soaked and water begins to drain from the drainage holes.

Cacti may be consumed?

You can either leave the pads whole, cut them into strips, or chop them into cubes, depending on how you intend to use this vegetable. Cacti that are edible can be eaten raw or cooked. They can be grilled, sautéed, boiled, simmered, or deep-fried. Their ideal serving texture is soft and crispy. The texture of overcooked pads will be slimy. Combine them with various ingredients to create a range of wholesome, nutrient-rich recipes. Here are some recommendations:

You might need to switch the water you’re using to boil the pads and re-boil them. It’s possible that the sap coming from the pad is thick. As a general rule, the sap will be thicker the thicker the pad. After draining, the pads are washed in cold water. Why not prepare a traditional Mexican salad with diced tomatoes, cilantro, jalapenos, onions, and lime juice? Salt and pepper are other good additions.


Season the pads well with salt and pepper if grilling them. When the pads are somewhat brown in color and soft to the touch, they are prepared. Additionally, you may season them with a dash of salt, a squeeze of lime juice, and a little olive oil.

Cactus pads can be added to various meals, either raw or cooked, to create flavorful, nutritious foods. They can be blended into a smoothie, or they can be diced and added as a topping to yogurt or cereal. Why not attempt incorporating them into stews, casseroles, and eggs. They make a delicious addition to quesadillas and salsa. You can choose to consume this adaptable, healthy vegetable alone, in a robust vegetable soup, in a fruit or vegetable salad, or even simply by itself! It can also be prepared into a jelly. Cactus pads can also be pickled and used to other meals as a condiment.