1. Japanese Giant Mantis: The Largest Mantis Found in Grassy Areas
The Japanese Giant Mantis is commonly seen in grassy areas along riverbanks or at the edges of forests. It is considered the largest praying mantis in Japan, with males measuring 68 to 92 mm and females 77 to 105 mm [1]. The maximum length of a female, 105 mm, is about 60 percent of the length of a new pencil (approximately 17 cm). Another species found in similar grasslands is the Korean Mantis. The Kyoto Prefecture Red Data Book describes this species as an "indicator species for flatland grassland environments." An indicator species is one whose presence serves as a benchmark for that specific environment. Because they live in grasslands near cities, the book points out that they can unexpectedly go extinct easily if development progresses [3]. This evaluation applies specifically to Kyoto Prefecture and does not necessarily reflect the situation across all of Japan.
Even among large mantises found in grass, there seem to be different preferences for where they live depending on the species. So, what kind of relatives might live in high places without grass?
2. Narrow-winged Mantis: A Mantis That Lives in Trees and Shrubs
The Narrow-winged Mantis is often found on trees in forests or in grass at the forest edges, frequently staying on shrubs. Its body length is 50 to 70 mm. It lays its egg cases (oothecae) on tree branches or walls of houses, and it overwinters as eggs [2]. Narrow-winged Mantises also live in parks in central Tokyo. An observation record from the Imperial Palace Outer Garden by the Ministry of the Environment notes that in August 2018, a Narrow-winged Mantis appeared before a staff member walking in Kitano-maru Park after being blown down from a camphor tree by the wind [10]. This is one example of them living in trees even in urban areas.
The Small Praying Mantis is described as an "arboreal" (tree-dwelling) species in the Kyoto Prefecture Red Data Book and is distributed in Honshu and Kyushu. Its egg case is rectangular, measuring about 5.0 by 12.0 mm, which is smaller than a 1-yen coin (20 mm in diameter), and it is laid on small twigs [5]. Since the Narrow-winged Mantis also attaches its egg cases to house walls, do they live only in grass and trees? Let us look near rivers and on the ground.
3. Pale-winged Mantis: A Mantis of Riverbank Grass and Fallen Leaves
The Pale-winged Mantis lives in grassy areas along riverbanks. According to the Kyoto Prefecture Red Data Book, it inhabits stable grasslands with little disturbance from flooding or human activity, and it is distributed from Hokkaido to the southwestern islands [4]. Even near rivers, this species prefers calm grasslands rather than areas that are constantly disturbed.
In contrast, the Ground Mantis lives close to the ground. While most praying mantises in Japan live among grass or in trees, the Ground Mantis is introduced as an unusual species that lives between fallen leaves on the ground [6]. Praying mantises in Japan belong to two families: Mantidae and Hymenopodidae. The number of species varies by reference, ranging from about 10 to 13 species [6]. Worldwide, there are said to be over 2,400 species, with many found in tropical regions [7]. Even just the Japanese species occupy a wide range of habitats: grasslands, forests, riverbanks, and leaf litter. Since the Pale-winged Mantis is said to inhabit Hokkaido as well, how far north does the Japanese Giant Mantis actually live?
4. What Sapporo Sightings Show About the Japanese Giant Mantis's Range
According to an October 2025 article in the Hokkaido Shimbun, the Japanese Giant Mantis, whose northern limit of habitat within Japan was previously thought to be southern Hokkaido, has been sighted in Sapporo City, including Nopporo Forest Park and Susukino. There have been over 100 reports [8]. Experts point out the possibility that "settlement," meaning repeated generation changes, is spreading throughout Hokkaido.
In another article, citing confirmation by the Tomakomai City Art Museum, it is stated that Japanese Giant Mantises, which were said not to exist north of Osamambe Town, were confirmed: 4 in one year and 6 the following year [9]. It is important to note that "settlement" has not been confirmed; experts say it may be spreading. The influence of global warming mentioned in article headlines is also a speculation ("may be"), not a confirmed cause.
In autumn, female Japanese Giant Mantises lay egg cases on small twigs, overwinter as eggs, and about 200 nymphs hatch simultaneously around April [1]. If individuals found in northern cities lay eggs and nymphs are born the next spring, that constitutes a "generation change." So, where do the praying mantises in your neighborhood live?
5. How to Find Where Praying Mantises Live Near You
Try this: look for praying mantis egg cases in nearby grass, shrubs, house walls, or tree branches. If you find an adult, record that too. In your notebook, write one word each for where you found it and what it looked like. Even if you do not find any, recording which places you looked at will help you compare findings on other days.
When walking near roadsides or riverbanks, watch your step and go with an adult. The habitats of the species we have looked at so far include grasslands, forest edges, treetops, riverbanks, and leaf litter. Comparing where you found them with the habitats listed in reference materials can reveal connections to your local scenery. The movements in Hokkaido also serve as a guide when looking for future news. For reference, the Ministry of the Environment website and the Kyoto Prefecture Red Data Book (which has explanations for each species) are useful [10].