Praying Mantises Can Kill Birds and Eat Their Brains All Around the World

Photo 9
A European mantis (Mantis religiosa) eating a black-chinned hummingbird (Archilochus alexandri) in Millwood, Colorado. Tom Vaughan

Like all great assassins, praying mantises are patient. Many species sit completely still, waiting until edible creatures comes within reach. Then they pounce, holding prey in a death grip with their spiked forelegs. Although they mostly hunt other insects, they can also eat birds. A new scientific review shows that mantises have been observed targeting birds all around the world, in every continent except Antarctica.

The paper, published in The Wilson Journal of Ornithology, compiles 147 confirmed incidents of mantis-bird predation in 13 countries on six continents. In all, 12 different types of mantises have been seen eating 24 types of birds, mostly hummingbirds.

"The fact that eating of birds by praying mantises is so widespread, both taxonomically as well as geographically speaking, is a spectacular discovery," says paper first author Martin Nyffeler, a zoologist at the University of Basel.

The brutality of these mantises should not be underestimated. Typically, they grab birds by the head to "pierce the skull to feed on brain tissue," says William Brown, a biologist with the State University of New York at Fredonia, who wasn't involved in the research. This head-first approach appears to be a typical tact, though further observations will be needed to confirm this, he adds.

Dietrich Mebs, a retired forensic ecologist at the University of Frankfurt, explains that the mantis's strength lies in its ability to surprise the birds, and to not let go once it has latched on. "They just hold [their prey], and they eat them while they are still alive, slowly and slowly until there is nothing left," he says. "It's really impressive."

The most capable bird assassin appears to be the Chinese mantis (Tenodera sinensis), which is native to China but has spread throughout the northeastern United States, where there are 25 recorded incidents of the creatures eating birds. Ruby-throated hummingbirds (Archilochus colubris), on the other hand, are the most common victims.

Other animals that praying mantises have been observed eating include "frogs, lizards, salamanders, newts, shrews, mice, snakes, tiny soft-shelled turtles, and even once a small bat," the authors write. Mebs notes that Chinese mantises can eat frogs and newts, including venomous species that would kill a human. But the mantises, somehow, are able to ingest and excrete the toxins without absorbing them.

A Chinese mantis (Tenodera sinensis) eating a ruby-throated hummingbird (Archilochus colubris) in Biggsville, Illinois. Randy Anderson (courtesy from ‘What’s That Bug?’)

Many of the mantis-bird attacks occurred at bird feeders and were predominantly upon hummingbirds. However, the insects have also been witnessed going after larger birds. In two separate observations on Long Island, ornithologists witnessed praying mantises attacking and latching on to a blue-headed vireo and a northern parula, although in both cases the humans intervened and the birds escaped.

Nyffeler says that mantises, which are sometimes introduced into suburban areas to control insect pests, might exact a significant toll on hummingbirds in these areas. However, Mebs notes that 147 confirmed cases worldwide is still a small number, and the impact of this type of predation is likely to be small. But Nyffeler suspects that many more birds may become prey to these mantises than has already been observed. "It can be expected that almost all of the more than 300 hummingbird species are vulnerable to predation by large mantises where they co-occur," he says.