8 Plants That Behave Suspiciously Like Animals

Plants are supposed to be the furniture of the natural world. They sit there. They photosynthesise. They do not, as a rule, count, hunt by smell, or install sanitation for a small mammal.

And yet. Botany has spent the last century and a half documenting species that break the deal, and the mechanisms turn out to be far weirder than the folklore around them. No brains involved. No nerves in the animal sense. Just turgor pressure, electrical signalling and a few million years of selection arriving at answers that look uncomfortably like decisions. Without further ado, eight plants handed the wrong instruction manual.

1. The Venus Flytrap, Which Can Count

Let’s kick things off with the celebrity. Each lobe carries three hair-like trichomes, and brushing one achieves nothing. Touch a second within roughly 20 seconds, or the same hair twice, and the trap shuts in about a tenth of a second.

The counting is literal. A 2016 paper in Current Biology by Jennifer Böhm and colleagues, titled with admirable bluntness “The Venus Flytrap Dionaea muscipula Counts Prey-Induced Action Potentials to Induce Sodium Uptake”, found that two electrical spikes close the trap, more than three switch on the genes for prey-digesting hydrolases, and enzyme output scales with how much the insect keeps struggling. A raindrop fires once and is ignored. A beetle fires repeatedly and is dissolved.

Where it stands now: badly. The species grows wild only within about 90 km of Wilmington, North Carolina, the population is down roughly 93 percent from a 1979 estimate of some 4.5 million plants, and the state made poaching a felony in 2014. One man drew 17 months in prison for lifting 970 of them. Buy cultivated stock, and start with the International Carnivorous Plant Society.

2. Bladderworts, Which Fire Faster Than You Can Perceive

Utricularia is the largest genus of carnivorous plants, roughly 233 species, on every continent except Antarctica. The traps are hollow bladders between 0.02 and 1.2 cm across. The plant pumps water out of each one until the walls cave inward under negative pressure, loading the structure like a drawn bow.

Then a water flea brushes a trigger hair. The door buckles, water floods in, the animal goes with it. A 2011 study in Proceedings of the Royal Society B led by Olivier Vincent timed it on high-speed video and found the suction completes in under a millisecond, among the fastest actions recorded anywhere in the plant kingdom. Francis Ernest Lloyd, who spent the 1940s poking bladderworts, found that a fired trap resets itself within 15 to 30 minutes.

3. The Corpse Flower, Which Heats Itself Up To Smell Worse

Amorphophallus titanum is endemic to limestone hills in western Sumatra, takes around ten years to flower for the first time, then repeats every three to seven years. The bloom lasts 24 to 36 hours. That is the entire show.

Chemists have taken the smell apart compound by compound and the list reads like a dare: dimethyl trisulfide for limburger cheese, trimethylamine for rotting fish, isovaleric acid for sweaty socks, and indole for exactly what you are imagining. The spadix then heats itself to roughly 37 degrees Celsius, human body temperature, generating a convection plume that lofts the stench up and out. Reports put the detectable range at up to 800 m. Carrion beetles and flesh flies arrive expecting a corpse and leave dusted in pollen.

The tallest on record reached 3.225 metres at Meise Botanic Garden in Belgium on 13 August 2024. Gardens livestream these blooms. People watch.

4. Dodder, Which Hunts By Smell

A Cuscuta seedling germinates with a clock running. It has almost no chlorophyll and roughly five to ten days to reach a host or die. So it sniffs.

Justin Runyon, Mark Mescher and Consuelo De Moraes showed how in Science in 2006. They grew seedlings near tomato plants, then near extracted tomato volatiles with no plant present, and the seedlings bent toward the smell by itself. Offered tomato against wheat, they picked tomato. One wheat compound actively repelled them. After contact the dodder drives haustoria into the host’s vascular system and starts swapping mRNA and small RNAs across the join, an intimacy most parasites never manage.

5. The Telegraph Plant, Which Actually Dances

Codariocalyx motorius grows across South and Southeast Asia and does something no houseplant has any business doing. Two small leaflets sit at the base of each large leaf and rotate continuously, completing a cycle every three to five minutes. Fast enough to watch. No time-lapse needed.

The motion wants warmth and generally quits below about 22 degrees Celsius. Darwin gave it several pages in The Power of Movement in Plants in 1880 and left the purpose open. The shortlist today: angling the big leaf toward light, and discouraging butterflies from laying eggs on a surface that will not hold still.

6. Mimosa Pudica, Which May Remember Being Dropped

Why it’s weird is the part nobody agrees on. The folding is settled science. Touch a leaflet, an action potential runs to the pulvinus at its base, water rushes out of those cells, turgor collapses and the leaf drops, then resets a few minutes later. Sold in seed packets alongside the rest of the impulse-buy shelf, it is most children’s first encounter with vegetation that reacts.

The argument is over Monica Gagliano’s 2014 work in Oecologia. She dropped potted mimosas 15 cm, over and over. The plants stopped bothering to fold. They stayed open through drops for at least 28 days, and when she shook them instead they folded instantly, which rules out exhaustion. Habituation is a textbook form of animal learning, so the claim landed hard.

Kasey Markel published a replication attempt in eLife in 2020 aimed at Gagliano’s related pea plant experiment, ran 121 plants with blinded scoring, and found nothing. The mimosa result has never been cleanly overturned. It has never been independently confirmed either. File under open.

7. Nepenthes lowii, Which Is Functionally A Toilet

High on the mountains of Borneo, between 1,650 and 2,600 m, one pitcher plant gave up on insects. The upper pitchers of Nepenthes lowii grow up to 28 cm tall and carry a stiff reflexed lid that secretes a white exudate mountain tree shrews consider worth the climb.

The shrew, Tupaia montana, straddles the opening and licks. Pitcher geometry matches its body length closely enough that the animal’s rear end sits directly over the mouth for the whole meal. You can see where this is heading. A 2009 paper in Biology Letters by Charles Clarke and colleagues found that mature plants drew 57 to 100 percent of their leaf nitrogen from tree shrew droppings. A 2010 follow-up put the colour of the lower lid right at the peak of the shrew’s visual sensitivity, so the plant is advertising too. Little Shop of Horrors never managed anything this undignified.

8. Boquila trifoliolata, The Vine That Copies Whatever It Climbs

Save the strangest for last. Boquila trifoliolata is a climbing vine from the temperate rainforests of Chile and southern Argentina, and its leaves change to resemble those of whichever plant it grows through. Precisely. Size, outline, colour, vein pattern, spininess at the tip, the angle the leaf holds, with recorded size changes of up to tenfold.

Ernesto Gianoli and Fernando Carrasco-Urra reported it in Current Biology in 2014 and called it mimetic polymorphism, since one vine can imitate several species at once, changing disguise leaf by leaf. Vines that mimicked got chewed on less than vines climbing a leafless support. More than 20 host species have been documented.

Nobody has produced a mechanism. A 2021 report claimed the vine also copied nearby plastic plants of the sort that turn up in discount homeware hauls and proposed rudimentary plant vision, which the field received with folded arms and sharp questions about method. Volatile chemicals, horizontal gene transfer and microbes have all been floated. None has been nailed down, and the vine carries on regardless.