By Garrett Genereux, Intern Naturalist
An assassin bug having a bee for lunch! Photo credit Dave Wilson Photography.
During this spooky time of year it is popular to post lists of scary things. Often times these lists feature animals such as the Great White shark or the Grizzly bear – animals that are actually quite frightening when encountered in nature. The five animals I am going to write about are “scary” but they will not get your instinctual-adrenaline pumping. These animals either appear scary or have some type of behavior that is scary, but in reality they pose little threat to us humans.
5. Assassin Bugs
These small (less than 40 mm) insects from the order Hemiptera (true bugs) are real-life vampires. Like their name suggests, they are highly-skilled predators. Assassin bugs employ camouflage coloring, dust, and sometimes even the exoskeletons of previous victims to hide and wait for their prey. They have also been known attack while flying. Once they have caught their prey, they use their straw-like mouth, called a rostrum, to inject saliva into their victim’s body. This isn’t just ordinary saliva; this saliva dissolves the inner tissues of their prey into liquid which the assassin bug then sucks out through the rostrum. There are 7,000 species worldwide. The Assassin bugs that can commonly be found in the prairie here at River Bend are quite benign. However, there are several species that inhabit parts of Central and South America that do feed on the blood of humans while they are sleeping. A few specific species of these blood-sucking Assassin bugs carry Chagas disease which can be fatal.
It is hard to forget a face like that! Photo credit Evets Lembek.
4. Wrinkle-faced Bat
This fruit-eating bat truly has a face that only a mother could love. Wrinkle-faced bats can be found in several Central and South American countries. The face of the male bat typically has more wrinkles than the female. These skin growths are thought to help direct sound waves to their ears. Also quite strange is that the male bats have a flap of skin on their neck that they can tuck their whole head into. Very interesting to note is that the wrinkle-faced bat’s head is wider than it is tall. This adaptation allows the bat to increase the strength of its bite. Some scientists have conjectured that this allows the Wrinkle-faced bat to eat tough-skinned fruit when soft fruit is not available.
Just remember it can’t hurt you! Photo credit Brujo.
3. Tailless Whip Scorpion
Although not a scorpion, this arachnid is perhaps more visually startling than its relative. Besides its six walking legs and two pedipalps (the two claw/pincer type legs near the animal’s mouth) it has a long appendage on each side of its body which is the “whip”. These appendages are not actually used as whips, but they do help catch prey. Typically the Tailless Whip scorpion walks sideways with its whips probing in front and behind as it walks feeling around for prey. Once it finds its prey it catches it with the pedipalps which have thornish spikes to ensure the prey does not get away. These arachnids do not have spinnerets or venom. There are 155 species that live in tropical and sub-tropical areas (so nothing to fear here in Minnesota). These animals prefer a humid environment.
For being so small it sure packs a punch! Photo credit Debby Ng.
2. Pistol Shrimp
Yes, a diminutive, plain-looking shrimp is at number two on this list. So if it doesn’t look frightening, then why is it on this list? Because it can do something quite spectacular that makes me thankful that it is fairly small and lives on the ocean floor far away from here. The Pistol shrimp, also known as the Snapping shrimp, is a predatory shrimp and has a very unique way of catching its prey. The shrimp has asymmetrical claws, with one of the claws being able to produce very loud (190 decibels) snapping noise that it uses to catch prey and communicate. When there are great populations of these shrimp they can actually disrupt sonar and cause noise pollution in the ocean due to their incredibly loud snapping. Now to the interesting part, how they catch their prey. Typically they feed on small fish and other shrimp. They lay in wait until they sense movement with their antennae. Then they cock back their snapping claw and aim it at their prey. Next it releases the claw (hence the pistol name) and it creates a cavitation bubble (the loud snapping noise creates a pressure difference in the water) which travels towards the prey at upwards of 100 km/hr and at a temperature of 9000 ⁰C. Yes you read that correctly. Nine. Thousand. Degrees. Celsius. And yes, that is hotter than the surface of the sun. This cavitation bubble eventually implodes, effectively and severely stunning the prey which allows the Pistol shrimp to grab it and bring it back to its burrow to feed. This shrimp lives in oceans worldwide.
So terrifying!!! Photo credit AussieBotanist.
1. House Centipede
This centipede is only five centimeters long, which is dramatically smaller than its largest cousin, the Amazonian Giant centipede, which can be up to 35 centimeters long. However, this centipede can be commonly found in your house, it moves uncommonly fast, and is not pleasant to look at. It may be of consolation that if this centipede is found in your house, it means that it is getting rid of other pests including ants, silverfish, small spiders, and even bed bugs. To catch this prey it moves very fast- up to .5 meters per second. Like many other centipedes, the house centipede uses venom to kill its prey. This species has specialized legs near its mouth that inject the venom instead of using mouthparts. House centipedes have been observed jumping onto their prey, lassoing them with their legs, and even bludgeoning their prey with their legs. Another adaptation that makes this centipede a great hunter is that it has highly developed eyes which are unusual among centipedes, although it still uses its antennae quite a bit. If you are quick enough to squash this arthropod, you better be accurate. House centipedes are notorious for being able to drop appendages that are trapped. However, if you squash too hard the centipede may drop all of its legs and essentially explodes. Originally from the Mediterranean, the House centipede is found almost worldwide. Just hope that the next time you move a piece of furniture you don’t see this creepy crawler speed away to its next hiding spot.
I hope that these animals did not scare you too much. Just remember that most of them don’t live here in Minnesota and that you as a human are much larger than they are so in reality they are probably more scared of you than you are of them. Enjoy Halloween!
Garrett Genereux is an intern naturalist for the River Bend Nature Center, a member supported non-profit dedicated to helping people discover, enjoy, understand and preserve the incredible natural world that surrounds us. Contact us at firstname.lastname@example.org or 507-332-7151.