At 21 inches (54 cm) long, a new species of stick insect found in Vietnam has nabbed the title of the second-longest insect ever described by science! The elongated twig mimic (Phryganistria heusii yentuensis), which looks like something you'd find after rolling a five or an eight [Ed. note: Obscure 'Jumanji' reference alert], is one of a dozen undescribed species of stick insects discovered by entomologists working for the Royal Belgian Institute of Natural Sciences (RBINS).

Entomologist Joachim Bresseel holding a female Phryganistria heusii yentuensis. Image: Bresseel & Constant/Royal Belgian Institute of Natural Sciences (RBINS)

Like many other animals, stick insects exhibit sexual dimorphism (one sex is larger or looks different than the other) ... but what you might not expect is that in this case, it's actually the female that is longer! "It's not uncommon for female stick insects to be twice the size of males," says entomologist and writer Gwen Pearson, who confirms the discovery of the giant tree-climber was met by 'strong language' from the researchers!

Through their expeditions, the team expects to double the number of known stick insects over the next few years – a particularly amazing feat given the difficulty of actually finding one. "[These insects] are almost only active at night," explains RBINS entomologist Jérôme Constant. "... and with their elongated body and green-brown colour, in shrubs and trees they are almost invisible. It often took us up to two hours before we returned to base camp with a collected specimen."

Image: Bresseel & Constant/RBINS

The authors note that the discovery of these new giant species is evidence that a large number of Vietnamese species are waiting to be described – and that's particularly concerning in an area where lush forests and marshes overlap dense human populations. 

Many rural Vietnamese communities rely on the collection of plants for building materials and fuel, but a largely unregulated industry poses a big threat to local wildlife. To help combat habitat loss, RBINS entomologists are working with local biologists to create a reference library of insects. That way, scientists in Vietnam will be able to spot and identify species, monitor biodiversity and prevent damage to crucial plants. 

Along with both live and preserved specimens gathered for museum collections, the team scooped up another form of precious cargo on the expedition ... stick insect eggs! Studying these masters of disguise in captivity will help researchers better understand their growth stages and bring us one step closer to being able to better protect them.

Want more giant walking sticks in your life? You can check out the rest of the newly described species here