Piles of garbage to blame for rise in number of rats

A graphic of rats.
A graphic of rats. Special to the Sun Herald

“Rats! Rats! Rats! Hundreds, thousands, millions of them” were in Bram Stoker’s movie Dracula.

That was a work of fiction. But in many parts of the world, there has been a dramatic increase in the population of rats. Estimates are that, on average, every human being on this planet lives within three meters of a rat.

Climate change may have something to do with it. But the biggest reason by far is our accumulation of garbage; its increase and careless disposal. Whether its throwing your fast food remains out of your car window or leaving unprotected bags of trash on the curb, disease-carrying rats thrive on it.

Rats carry a plethora of pathogens that they are quite ready to pass on to us: Cryptosporidiosis; E. coli, hoof and mouth disease, salmonella, tuberculosis, Weil’s disease. Not to mention the plague. In the sixth century, diseased rats put the final nail in the coffin of the Roman empire by wiping out over 100 million people. Once again beginning in 1348, the Black Death managed to wipe out a third of the people in Europe.

Like all living things, rats need food, water and shelter. They will eat almost anything organic: eggs, feces, flowers, fruit, meat, snails, even themselves. Rats burrow. But, they prefer ready-made habitats such as attics, under floors, in sheds and wood piles. However, just because you see a rat in your yard doesn’t mean they’re living with you. They will travel several blocks, often along fences and through vegetation, to reach a source of food or water.

There are two types of domestic rat: the Norway rat and the black rat. The Norway rat is grey-brown with a large body and a short tail. The Black rat and has a smaller body and longer tail. The Norway rat likes underground burrows, the black rat likes attics.

There are obvious indicators of rat infestations. Accumulations of their droppings. These are black, thin and one centimeter long. Rat runs are another sign. These are created over time when rats establish a distinct path along walls and fences. There will be a greasy smear running along walls and fences where the rats continuously rub against them. Rats gnaw plastic, wires, wood and other things.

If you think you have a rat problem, there are a number of things you can do. First, talk to your neighbors. The problem may not be just yours. Encourage them to act in coordination with you.

Baits are a good way to reduce rat numbers. But first, rats must be deprived of food. The more food available, the less likely they will be to take up the baits. Wrap up any scraps before throwing them away. Keep your garbage cans tightly sealed. Store any pet food in tight, metal cans and don’t let pet food stay out over night.

If you have any fruit trees, collect any fallen fruit. Pick up any dog droppings. Baits are available in a number of forms. Grain-like baits, palletized baits and solid baits are the most common. The draw-back to baits is that they’re are slow acting and can take as much as two days to work.

Shelter is another necessity for rats. If you have any firewood, stack it at least 30 centimeters off the ground and as far from buildings as feasible. Clear your property of all rubbish. Prune branches away from your house. Black rats get into your house by using branches that touch or overhang your roof.

Repair damage to vents. Check water, gas and electrical conduits, flashings for chimneys and air conditioning lines. Any gaps grater than five millimeters must be closed and sealed. A rat can squeeze through a hole as small as 12 millimeters.

To kill a rat, the safest method is the old-fashioned snap trap. The wooden trap is sold in hardware stores every where. If you use a trap, place it where you’re noticed activity. Don’t “set” the trap. Let it stay in place for a few days. Rats are neophobic. They avoid anything new in their environment.

Once they’ve become used to the trap, set it. Use a piece of apple, chocolate, potato, raw bacon or peanut butter. Place the trap where the rats will pass directly over the trigger as they follow their trail. Make certain that the trap is away from children and pets. Use enough traps to quickly eliminate the infestation. Using too few traps is a common mistake.

Glue boards are another alternative. These trap and hold any rat trying to cross over them. Two or three traps side-by-side will be more effective than a single trap. Finally, There is no valid scientific evidence that sound or electronic devices control rats.

Tim Lockley, a specialist in entomology, is retired from a 30-year career as a research scientist for the U.S. Department of Agriculture. For answers to individual questions, please send a stamped, self-addressed envelope to Tim Lockley, c/o Sun Herald, P.O. Box 4567, Biloxi MS 39535.