Evening star. [volume] (Washington, D.C.) 1854-1972, 1931-08-23
HOM|NG INSTINCT
OF MICE IS SHOWN
Experiments With Rodents
Prove They Can Return
Over Long Distances.
BY THOMAS r. HENRY.

hX THOMAS II. HENRY.
Experiments showing remarkable
ability in mice to return home over
long distances have just been reported
to the American Society of Mann
malogists here
A sense of direction or homing in
etinct analogous to that of bees or
pigeons is suggested in the report Of
the experiments in the current issue Of
the journal Of the socisty. The work,
reported by G. J. and Adolph Murie,
was done with the deer mouse, COM
mon habitant OF the Rocky Mountain
area, through two seasons
The little animals were trapped and
their ears marked for Identification.
Then they were carried in closed con-
tanners various distances from camp
alld released. Many returned and were
caught days later in the traps on the
original location. One returned to the
old home over a distance of approx
mately 2 miles in two days. Four out
OF 40 went over mile to get back
home. Many trayersed shorter dis
tar1ces successfully. The returns were
necessarily very incomplete, because not
all who returned ventured into the traps
again, some were killed by other ami
mails on the way, and 1t was shown
that not a few preferred the new home
to the old and stayed there. The num-
ICChptuEeO, II Is pOlIlJEQ OUT III LIE
report. was too great to be explained
By mere ainless wanderings.
Range Over Wide Area.
Another possibility considered by the
two experimenters was that these mice
ordinarily range over a wide area and
become familiar with the landmarks.
To test this q large number were trap
ped at the camp, their ears marked,
and Immediately released. Then traps
were scattered about the place to de-
termine the extent of their ordinary
were recaptured. 1t was found that
the great majority remain within a
radius OF about 100 yards.
One mouse which returned from q
distance of mile and the animal that
returned miles were from 8 to weeks
old. The animals spend considerable
time In the nest after birth, so that
these could not possibly have had time
to become familiar with the outlying
territory. They saw nothing of the
landscape through which they were
taken, SO no landmarks could have
been fixed In their minds.
The investigation started with a
casual experiment two years ago in
which . marked mouse Unexpectedly
Tet1irned q distance Of 100 yards after
being released from the trap. The two
experimenters then trapped and re-
leased 10 others at this distance, and
after recapture repeatedly released
them at greater and greater distances.
until all disappeared. The greatest
distance was ] mile This was open
to the Interpretation that the animals
became familiar with the landmarks of
part Of the trail each time they passed
over II.
Followed Straight Lines.
The next Summer the biologists re-
turned TO the same place and trapped
Is many mice as they could, releasing
them at q distance OF ] mile without
any intermediate steps. Some made
their way back through heavy forest
and undergrowth, while others. released
in the opposite direction, showed
slightly better ability to get home over
open country. The evidence indicates
that they moved In almost a straight
line, as do other animals with an al
legged -homing instinct" The expert
mentors always travelled In as near q
straight line as the nature of the coun-
Try permitted IN taking the animals to
the point where they were to be re-
leased.
The almost uncanny judgment of
direction Is even more remarkable
since the creatures were shown By
other experiments to have no great
desire to return there. If the new
habitat suits them they proceed to
settle down. One lot was trapped 4
miles away and released at the camp.
During the next few days several Of
these were recaptured within a short
radius. 1t Is explained that most Of
the mice In the area had been trapped
before 50 that the newcomers found
comfortable Abandoned homes await
ing them. Whether other mice share
70 any extent this remarkable ability
Of the deer mouse is unknown. Some
thing Of the kind has been observed
IN the case OF domestic dogs who seem
70 have strong drive to return to a
loved home over great distances of I'M
familiar country.
Homlng Instinct Seen.
This data, the report says appears
% show that although various factors
probably influence the behavior OF the
mice released, mere chance does NOT
satisfactorily account for the ability
Of q certain number to return to the
original place Of capture from distances
Of ! 70 2 miles. One is tempted
70 believe that q sense Of direction
or homing instinct plays some part.
IT Is diflcult to define exactly a
homtng instinct We are familiar with
the abilities Of homing pigeons, migra-
tory birds and certain insects. What
ever such abilities may be called, it
seems likely that mammals share them
70 . certain degree. The desire to re-
turn TO the home range no doubt
varies with species as well as with in
dtvtduals, but at any rate our data
appear 70 show that the deer mice
have remarkable ability"
Further work with the homirg ability
OF mammals, especially other varieties
OF mice, Is urged to clear up some cen
1ustng factors In this experiment The
natural dangers TO which mice are ex-
posed in the open country where such
work must be carried on, 1t is pointed
out, makes this study much more Diff
cult than In the case Of such creatures
AZ tIlaecfs whose heha s.inr On n he sAr,cland