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A typical fruit rat is between 13 to 18 inches long from nose
to tail. It is commonly known as the black rat, but is often dark brown in color. Unlike other rats, their tails
are longer than the length of their bodies and they have large ears. Fruit rats will nest in trees, woodpiles,
garbage and plants, but they generally like inside high places, like attics. They sometimes co-exist with sewer
rats, though they like to be up high. They are good climbers and only need a hole the size of a quarter to gain
entry. Fruit Rats can have up to 8 liters per year each bearing 6-8 rats. They become sexually active 2-3 months
after birth. Fruit Rats are most active one hour after sunset and one hour before dawn. They primarily consume
fruits and nuts, although they will eat anything. They tend to hoard food for consuming later. They are known for
hollowing out citrus fruit in trees or on the ground.
The fruit rat is an introduced species of rat native to southern
Asia. It was brought to America on the first ships to reach the New World and has spread around the world. This rat
is the same species that carried the bubonic plague around the world and is also the reservoir host for murine
typhus. Fruit rats are the worst rodent pest in the state of Florida and most abundant. The Norway rat (Rattus
norvegicus) that is familiar to most people is not common in Florida, but still seen.
Fruit rats consume and destroy stored animal and human food, attack
fruit crops, and take up residence in attics, soffits, hollow walls, and out-buildings.
When they invade buildings they chew through wires (potentially
starting fires), gnaw through plastic and lead water pipes, make holes in walls and cause other structural damage.
The secretive, nocturnal nature of rat’s means that they often go unnoticed in a neighborhood until dooryard citrus
and other fruit starts to ripen. They then make their presence known with a vengeance. In citrus, papaya,
cantaloupe and watermelon, the characteristic damage is a circular hole about the size of a quarter or half dollar
and the whole fruit hollowed out.
As we progress through the citrus season (from September through March), the fruit rats that may have been living
quietly around your house or grove make themselves known. Hollowed-out fruit is the most common evidence of roof
rats. In apples, peaches, tomatoes, carambolas, bananas, pineapples and mangos, large sections of fruit are eaten
away. They remove whole fruits from blueberries, figs, grapes, strawberries, lichees, Surinam cherry, loquat, and
dates, so the damage is less noticeable or birds are blamed for the missing fruit. In Florida, fruit rats - along
with our native cotton rat - destroy or damage a great deal of sugar cane every year.
Adult fruit rats are 12-14 inches long (30-36cm) and weigh 5-10oz
(150-250g). The tail of a fruit rat is longer than the head and body length: hairless, scaly, and black
The body is sleek and graceful with prominent ears and eyes. There
are three color phases seen in Florida: black back with a slate gray belly, gray back with lighter gray belly, and
brownish gray above with a white or cream colored belly. In addition to the damage done to fruit, other evidence
includes black banana-shaped droppings about 1/4-1/2 inch long (about 1 cm) and dark smears or rub marks seen along
the rat's travel routes.
Fruit rats are arboreal (tree-living) by nature. They are similar to
squirrels in their ability to move through trees and along vines and wires. They often use utility lines and tree
branches to reach food and water and to enter buildings. They prefer nesting above the ground in attics, soffits,
piles of debris, hollow trees, skirts of old fronds on palm trees, and in Quaker parrot nests, but will nest in
burrows in canal banks and under sidewalks or stacks of materials stored on the ground.
Fruit rats are omnivores (plant- and animal-eating) but very fond of
fruit. They feed on most cultivated fruits and eat many native fruits and nuts. They also feed on livestock feed,
pet food, bird seed in feeders and garbage. They contaminate and damage much more than they actually eat. They will
chew through lead and plastic pipes to reach water. They will travel 150yds. (135m.) from their den to reach food
Fruit rats reach sexual maturity at 3 to 4 months of age. In
Florida, they breed year-round, with peak breeding activity in spring and fall. The litters of 5 to 8 pups are born
after a gestation period of 21 to 23 days. A female roof rat can have 4 or 5 liters per year.
Control of Fruit rats is not an easy task. Integrated pest
management is needed to control these pests. The tools of Integrated Pest Management (IPM) include inspection;
cultural control (prevention and habitat management); physical control (trapping and exclusion); biological control
(predators); and--if needed--chemical control (rodenticides and repellents).
City of St. Petersburg (FL) Sanitation Department offers a Rodent Line at 727-893-7360 for citizens who have
spotted a rat on their property. They will assist in controlling rats on the outside of one's property and in their
neighborhood. They will send out a Rodent Control Technician to inspect the property, place a tamper-resistant bait
station in a rodent-attracting location outdoors and advise on how to help rat prevention. In-home rodent control
requires a private exterminator.
Because fruit rats are such good climbers and swimmers it is hard to
completely exclude them from your yard, grove, or orchard. Here are some cultural techniques to help you reduce
damage: Proper spacing and pruning of fruit trees your fruit trees should be isolated, not touching fences,
overhead wires, or the branches of other trees. Fruit rats will run along fence stringer boards or support poles,
phone and cable TV wires, and tree branches to reach your fruit tree. Lower branches of the tree should not touch
the ground. A low-hanging skirt of drooping branches gives the rats additional access routes and provides them with
protective cover while feeding. Prune trees so that the ground under them is open and visible. This lack of cover
makes the rats uncomfortable and more susceptible to predators.
Rat guards on the trunks will keep the rats out of trees. Rat guards
can be as simple as a piece of sheet metal 18-24 inches wide and as long as the circumference of the tree plus two
inches. Use a piece of wire bent like a giant staple to secure the ends of the sheet metal without penetrating the
tree. Put the back of the wire against the tree's trunk and insert the two ends of the wire through holes in the
sheet metal. Then bend the wire outward to hold the ends of the rat guard together.
If your tree has a short or forked trunk, then a sheet metal wall, 2
feet tall (60 cm), around the tree will reduce rodent access to it. If wires go through the crown of the tree or
your tree touches a fence or branches of another tree, then rat guards are useless--the tree must be isolated for
rat guards to work. Sanitation is also important. Remove all fallen fruit. If you have more fruit than you can use,
contact your local food banks or become involved with community fruit salvage operations.
Integrated Pest Management relies on biological control
agents as a cost-effective way of controlling pests. We have many allies in our war on
Snakes - In Florida, many species of snake help control roof
rats. Yellow rat snake, gray rat snakes, corn or red rat snakes, black racers, king snakes, coachwhips and indigo
snakes all prey on fruit rats. Even our venomous rattlesnakes and cottonmouths eat lots of
Cautionary Tale: The importance of snakes in rat control was made clear in the following report: A dog
kennel worker took it upon himself to eliminate all of the snakes at his place of work. Once the rat snakes had
been killed, the fruit rat population exploded. It took two years, hundreds of people-hours, and thousands of
dollars to get control of the rats and repair the structural damage the rats had caused. This does not include the
hundreds of pounds of dog food the rats ate and contaminated. The economic cost of removing the rats' natural
predators was obvious.
Raptors, hawks and owls, especially barn owls, are very effective at
killing fruit rats. Keeping the area around fruit trees open makes hunting easier for birds of prey.
Cats and Dogs? Many people believe that cats and dogs will keep rats out of their yards and fruit trees. But,
because fruit rats are so arboreal, they are usually able to get into attics and fruit trees without ever coming to
the ground. Rats quickly learn safe travel routes through yards to avoid terrestrial predators. Cats will kill
dispersing juvenile rats, but are rarely able to handle an adult fruit rat within its own
Many claims are made about ultrasonic and electromagnetic devices'
repelling rodents from buildings and yards. There is no evidence that these devices will or can drive rodents from
their home range. There is evidence that ultrasonic devices can cause hearing loss in pets, especially