Cockroaches: These pesky roommates may be creepy, but they help clean up after you. Cockroaches eat mold and the eggs of bedbugs and lice.
Mosquitoes: These guys suck - literally. They are also the major food source for many species, including freshwater fish. Don't discount these guys.
Bats: Apart from reminding you of Dracula, bats are kind of scary. But they are really helpful because they eats tons of bugs. Scientists say they save us billions in pest control services.
Earthworms: These slimy things are not just good for fishing bait. They also help keep the plants in your gardens alive by creating holes in the soil for oxygen and nutrients to travel through.
Spiders: Like some of the other species in this lists, spiders help keep pests in control. They are also helping you stay healthy by eating bugs that could transmit a disease
RELATED: Check out these islands that are overrun with animals:
Islands overrun with animals
Islands overrun with animals
Ilha da Queimada Grande, Brazil: Snakes
Scarily close to São Paulo and Rio de Janeiro, there is an island so dangerous, the government strictly controls all visits there. There are between 2,000 to 4,000 golden lancehead vipers, one of the deadliest snakes in the entire world. Its incredibly potent venom can 'melt human flesh.'
Hundreds of freely roaming rabbits take over 'Bunny Island' in Japan, drawing tourists from all over. But once upon a time, this same island was used to test chemical weapons during WWII.
Lambay, Ireland: Wallabies
Not far from Dublin, there is a virtually abandoned island that is overtaken by wallabies. The island first became home to the Oceanic animal in the 1950s and 1960s when a well-known, wealthy family decided to raise exotic animals. Some escaped into the bushes and the rest is history. How do the Australian animals survive the cold, Irish winters? They grow adorable thick coats!
The sacred Japanese island is home to shrines, temples and countless tame deer. Deer are believed to have lived on the island for 6,000 years and are a messengers of the local gods. The natives' respect for the animals has made them extremely sociable.
Assateague Island National Seashore, Maryland: Horses
Hundreds of feral horses live on this remote barrier island on the east coast of the United States. Experts speculate they are the descendants of horses brought to surrounding islands in the late 17th century to avoid fencing laws and taxation.
Kauai, Hawaii: Chickens
The tropical island is stuffed with thousands of feral chickens. And without natural predators, the population is rapidly increasing. Scientists think the boom started in 1992, after Hurricane Iniki destroyed chicken enclosures.
Miyagi Zao Fox Village, Japan: Foxes
Hidden in the Japanese mountains is a 'village' that is chock full of foxes. Trickster foxes play an important role in Japanese folk culture and they are just plain adorable. But beware when visiting here -- you can feed these little guys, but they are not domesticated and can bite.
Photo: Instagram via @bikke_the_chip
Aoshima Island, Japan: Cats
More than100 felines have take over this Japanese island. In fact, cats outnumber human residents one to six.
Yes, New Zealand is known for its sheep and sheep-related exports. But many people don't know that there are 6 sheep for every one human being. New Zealand sheep numbers peaked in 1982, with a total of 70.3 million sheep, but as of 2015, there were still nearly 30 million sheep. That's a lot of wool.
Christmas Island, Australia: Red crabs
Tens of millions of these unusual crustaceans live on Christmas Island. Impregnated female crabs burrow in the moist forest floors and head to ocean when their eggs are ready to hatch. After about a month in the ocean, the baby crabs migrate back to the forest, where they live for the first three years of their life.