Cactus
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40 free Cactus trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Cacti are some of the toughest and strangest plants on Earth. They thrive where rain may not fall for months, defend themselves with needle-sharp spines, and still manage to produce some of the showiest flowers in the plant world. They also turn up in kitchens, on flags, in video games and on windowsills every winter. This quiz covers the whole family: how a cactus stores and saves water, the best-known species of the deserts of North and South America, the birds and insects that live on them, and the foods, dyes and traditions people have made from them. A few questions wander into film, music, sport and wartime history, where the word cactus pops up in unexpected places. It suits gardeners, houseplant collectors, desert hikers, teachers planning a plant unit and anyone hosting a nature-themed trivia round. Every answer comes with a short explanation, so you will finish knowing more than when you started.
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Q 01Which giant cactus of the Sonoran Desert may not sprout its first arm until it is 75 years old?
Saguaro
Saguaro cacti are the largest in the United States, yet some never grow an arm at all, and the tallest one ever measured had none.
Q 02Which spiky source of tequila is often mistaken for a cactus but belongs to the asparagus family?
Agave
Agave and cacti look alike because both adapted to dry places, probably a case of convergent evolution; they are not close relatives.
Q 03On the flag of Mexico, which creature perches on a cactus while devouring a snake?
An eagle
An eagle on a cactus was, in Aztec legend, the sign that showed the wandering people where to found their city.
Q 04Pitaya, the pink-skinned harvest of a climbing cactus from Mexico and Central America, is better known by which name?
Dragon fruit
Dragon fruit grows on a cactus that winds around nearby trees for support and can climb 8 to 10 meters off the ground.
Q 05Thorns are modified branches, botanists say, while cactus spines are modified versions of which plant part?
Leaves
Leaves reshaped into spines lose far less water, and the spines also shade the cactus and keep hungry animals away.
Q 06To avoid losing water in the desert heat, when do most cacti open their pores to take in carbon dioxide?
At night
At night the air is cooler, so far less water escapes; the gas is stored as an acid until daylight returns.
Q 07Which actress won an Academy Award for her first major film role, in the 1969 comedy Cactus Flower?
Goldie Hawn
Goldie Hawn, until then a regular on TV's Laugh-In, won Best Supporting Actress playing opposite Walter Matthau and Ingrid Bergman.
Q 08Which brother of Snoopy lives in the desert near Needles, California, with only cacti and rocks for company?
Spike
Spike was named after a dog Charles Schulz had as a boy, and the Schulz family itself lived in Needles for two years.
Q 09Which sport holds spring training in two circuits nicknamed the Cactus League and the Grapefruit League?
Baseball
Baseball named its two preseason circuits after plants typical of the states that host them; the grapefruit stands for Florida.
Q 10Which percussion instrument is traditionally a dried cactus tube with its own spines driven inward like nails?
Rainstick
A rainstick is filled with pebbles or dried beans that bounce off the spines as they fall, making a sound like falling rain.
Q 11The bright red or yellow top of a grafted moon cactus cannot survive alone because it lacks which pigment?
Chlorophyll
Chlorophyll is what lets a plant feed itself from sunlight, so the colorful mutant is grafted onto a green cactus that feeds it.
Q 12On which islands explored by Charles Darwin do Opuntia cacti grow as trees, some reaching 12 meters tall?
The Galápagos
The Galápagos has cactus trees found nowhere else on Earth, and one variety carries spines up to 25 centimeters long.
Q 13The lesser long-nosed, a key pollinator of giant desert cacti that bloom after dark, is what kind of animal?
A bat
A bat of this species may migrate 1,600 kilometers a year, following the flowering of its food plants north out of Mexico each spring.
Q 21In Mexican cooking, what are the flat cactus pads called that go into salads, soups and stews?
Nopales
Nopales take their name from the Nahuatl word nohpalli, and the pads of almost all Opuntia species are edible, raw or cooked.
Q 22Which video game series features the Cactuar, a dashing cactus creature feared for its 1000 Needles attack?
Final Fantasy
Final Fantasy introduced the Cactuar as an enemy in its sixth game, with a face modeled on haniwa, the clay figures of ancient Japan.
Q 23Which cactus is nicknamed jumping because its spiny segments detach at a touch and cling to passing animals?
Cholla
Cholla stems that hitch a ride on desert animals are carried a short way, and young plants start from the pieces that fall off.
Q 14The word cactus comes, by way of Latin, from which ancient language's name for a spiny plant?
Greek
Greek kaktos was the name Theophrastus used for a spiny plant that may have been the cardoon; nobody is now sure which plant he meant.
Q 15Aloes, jade plants and almost all cacti are counted among which broad group of drought-hardy plants?
Succulents
Succulents have thickened, fleshy parts adapted to store water, a trick found in many separate plant families, not just the cactus family.
Q 16Which US state adopted the white blossom of a giant desert cactus as its official state flower?
Arizona
Arizona's state flower opens well after sunset and closes by the middle of the next afternoon, so each bloom lasts less than a day.
Q 17The golden ball cactus, a spiny yellow sphere from Mexico, is nicknamed the mother-in-law's what?
Cushion
Cushion is one version of the joke and chair is another; though grown in gardens around the world, the plant is rare and endangered in the wild.
Q 18Christmas cactus, the holiday houseplant, grows wild on trees and rocks in which country's coastal mountains?
Brazil
Brazil calls the plant Flor de Maio, the May flower, because south of the equator it blooms in May rather than December.
Q 19Which cactus with flat, paddle-shaped pads bears an edible fruit known in Spanish as tuna?
Prickly pear
Prickly pear fruit is eaten across Mexico and the Mediterranean and is blended into the chilled drinks called aguas frescas.
Q 20To catch brief desert showers, the roots of most ground-growing cacti spread in which pattern?
Wide and shallow
Wide and shallow roots sit close to the surface, where they quickly absorb any water that reaches the ground before it is gone.
Q 24Which stout, ribbed desert plant is nicknamed the compass because older specimens lean toward the south?
Barrel cactus
Barrel cactus plants may lean because fierce afternoon sun slows growth on the exposed side, and old ones can tip far enough to uproot themselves.
Q 25Which small bump, the feature that identifies a plant as a cactus, sprouts both spines and flowers?
Areole
An areole is really a highly shortened branch, which is why new stems can grow from one as well as spines.
Q 26What are the tiny barbed bristles of Opuntia cacti called, which detach at a touch and lodge in the skin?
Glochids
Glochids grow in tufts of hundreds and, being barbed, are far harder to get out of skin than a cactus's big spines.
Q 27Which insect, brushed from cactus pads and dried, yields the red dye carmine used in food and lipstick?
Cochineal
Cochineal was shipped from the New World to Spain from the 1520s; before that, Europe colored its cloth red with a dye called kermes.
Q 28Which small, spineless cactus of the Chihuahuan Desert is taken as a sacrament by the Native American Church?
Peyote
Peyote takes its name from a Nahuatl word said to mean caterpillar or its cocoon, after the plant's downy top, and it can need around ten years to mature.
Q 29Which country, its farmland overrun by cacti, was rescued in the 1920s by a moth brought from Argentina?
Australia
Australia's prickly pear covered tens of millions of acres by 1920; the moth, released in 1925, almost wiped it out, and one Queensland town built the insect a monument.
Q 30Which tiny desert bird, the smallest of its kind in the world, nests in old woodpecker holes in giant cacti?
Elf owl
Elf owl adults are about the size of a sparrow, and pairs usually pick an abandoned north-facing hole in which to raise their young.