Senses of Rats
A Norway rat's snout is blunt; the roof rat's
Rats have poor vision. They are nearly color
snout is pointed.
blind, and react to shapes and movement rather than
identifying objects by sight. Thirty to forty-five feet is
HABITS OF RATS
the limit of their vision. Their eyes are adapted to dim
Rats must be understood to be controlled.
Knowledge of their life histories, habitat and food
Other senses, however, compensate for poor
requirements, patterns of behavior, range and other
vision. They use their sensitive nose to locate food,
factors is essential to their management.
follow pathways, tell whether another rat is friend or
The Norway and Roof rats have similar habits.
foe, and identify new objects in their territory. They
Most of the discussions below apply to either kind of
use long whiskers and guard hairs to "touch" their way
rat. Where differences are important for control
through dark burrows, pipe chases, wall voids, and
purposes, however, the differences will be highlighted.
other runways. Their ears detect faint sounds that
signal danger. Rats can taste certain chemicals at a
parts-per-million concentration. [This explains why
rats often reject baits or avoid traps that have been
contaminated with insecticides.] Finally, rats have an
A mature female rat can give birth to about 20
excellent sense of balance which allows them to walk
young in a year (4 to 6 at a time), if she lives that
on wires and always land on their feet in a fall.
long. The average life span of a rat in the field is less
than one year; females live longer than males.
The young are born in a nest. They are hairless,
Fear of New Objects (Neophobia)
and their eyes and ears are closed. Within two weeks
Rats are wary of anything new that appears in
their eyes and ears open, they become furry and rat-
their territory. A bait station, a trap, a block of wood
like, and they begin exploring the nest area. In the
will be avoided for a few days until the rats become
third week they begin to eat solid food, and imitate
familiar with the new object; even then, they approach
their mother to forage, escape, and watch for danger.
cautiously, This fear of new objects can make baiting
If the mother rat has become wary of rodenticides
and trapping difficult. Rats will avoid poison bait when
or traps, many of her young will learn to avoid them.
it is first placed. Later, they may nibble warily. If the
This learning experience can make control difficult in
poison bait makes them ill, but doesn't kill them, they
will avoid similar baits or stations in the future.
sites where long term rodent control programs have
been unsuccessful in the past.
Young are totally weaned at four or five weeks
Food & Water
old. They then weigh about 1 l/2 ounces. At three
Rats need about one ounce of food daily. Norway
months, the young are independent of their mother.
and roof rats prefer different types of food. Norway
They will mate and continue the cycle in the same
rats prefer protein-based foods such as meat, fish,
location or will migrate to a new, unoccupied nest
insects, pet food, nuts, and grain. Household garbage
is ideal food for Norway rats. Roof rats prefer plant
materials such as fruits, nuts, seeds, berries,
vegetables, and tree bark. They occasionally feed on
Rats are social animals and live in colonies with
garbage and meats. Each rat species, however, will
well-defined territories that they mark with urine and
feed on nonpreferred food if nothing else is available.
glandular secretions. The colony has a complex social
Rats often cache or hoard food in hidden areas.
hierarchy with a dominant male leader and a "pecking
This food may or may not be eaten when other food
order" of subordinate males and ranking females. The
supplies run short. Hoarding is important for two
strongest and most dominant animals occupy the best
reasons. First, rats may be moving a toxic bait into a
nest and resting sites, and feed at their leisure.
location where the label does not permit it to be.
Weaker, subordinate rats are pushed out to less
Second, rats may be hoarding poison bait while
favorable sites, or forced out of the territory
feeding on their regular food; thus, a baiting program
Rats are aggressive, and social conflicts are most
Rats need water every day. The amount varies,
depending on the moisture content of their food, but is
common at feeding sites, prime resting areas, and
usually around 1/2 to one fluid ounce. Rats prefer to
territorial boundaries. Females fiercely defend their
nest where water is easily available.
nest and young from other rats.
Module Three Chapter 2, Pg 4