Praying mantids are fast and can snatch a hummingbird out of the air. Photo: Credit: Tom Vaughan/FeVa Fotos

It’s rare, but it’s gruesome. A praying mantis lurks on a hummingbird feeder, watching carefully as a hummingbird hovers near the sugary water. With one quick motion, the mantis grabs at the hummingbird—and misses.

Video Credit: Mike Lewinski

Hummingbirds don’t always get a second chance. Pictures of these incidents, like the one above, show mantids improbably dangling from feeders with bloodied hummers at the end of their claws. Then, they start eating the innards. But wait, you must be thinking—aren’t hummingbirds as big as mantises?

Below, we breakdown how these insects attack large prey, and how to keep your backyard hummingbirds safe.

What's the size difference between the average mantis and the average hummingbird?

On average, mantids and hummingbirds are the same length. But compare a hummingbird to a mantis's usual meal, and the size difference is quite astounding. Hummingbirds tend to be about 4 inches long (though some species, like the Giant Hummingbird, are twice that size), while bees and wasps are about half an inch long. That makes hummingbirds eight times bigger than what a mantid usually eats.

Some of a mantises favorite meals are drawn to the sugary water of the hummingbird feeder, so feeders are a great place for mantids to await their prey.

What would make a mantis go after a hummingbird?

A mantis has to be very hungry to go after a meal as large as a hummingbird, especially since the mantis will not be able to eat the whole thing, says Dr. Joshua Martin, from Case Western Reserve University. Because of this, hummingbirds are just a small part of the mantis diet.

"We know that mantises use the size of the prey and its speed relative to its size to decide to whether to strike," Martin says. Bees and wasps are fast, so mantids need to react quickly to catch them. Hummingbirds are also fast, so a mantis might react before discerning what it caught.

Hunger may also make the mantids' eyes bigger than its belly. "As a mantis gets hungry, as the time from its last meal gets longer, this 'idea' of what constitutes prey gets broader and broader, and she'll strike at larger targets," Martin says.

Why is a mantis such an effective predator?

Mantids have rapid reflexes and their forearms and legs have spikes to pin prey down. They can also turn their heads 180 degrees, so prey have little chance of going unnoticed. Mantids also have the uncanny ability to blend into their surroundings, and with their knack for staying very still, it's very hard for birds and insects to identify them.

How can you protect your backyard hummingbirds?

Even though there is a low risk that a mantis will snatch a hummingbird, there are ways to prevent these incidents. Placing a hummingbird feeder away from shrubbery or trees, where mantids can disguise themselves, is one effective method. Another method is to place a wide bird feeder cover above the humming bird feeder. The cover is intended as a deterrent, though many species of mantids can fly.

The easiest method is to gently take a mantis off a feeder with a stick and move it to another location. Other solutions, like insecticides, may do more harm than good to other creatures (including hummingbirds) in the back yard.

Should I try to ban mantids from my yard?

Mantids sure seem evil—like a few other species, the female eats the male after mating. But the reality is that mantids are actually great insects to have in the garden. They eat bugs and they're kind of cool looking. Keeping them around is also a good idea if you're growing vegetables.

"Mantises are probably eating far more pestiferous insects [than hummingbirds] while also being eaten themselves by other birds," says Dr. Gavin Svenson, head of invertebrate zoology at the Cleveland Museum of Natural History.

Let's just hope you can turn the mantis away before you have to witness a brutal takedown of a hummingbird.