116 
Forest and Stream 
STUDIES IN TROUT PSYCHOLOGY 
EXPERIMENTS WITH DIFFERENT KINDS OF FOOD WHEN FED 
TO CAPTIVE TROUT PRODUCE SOME STARTLING RESULTS 
W HY a trout rises to a fly is an 
old question. Is it the form, 
more or less accurately repre¬ 
senting the natural insect, 
that attracts attention and provokes re¬ 
sponse? Or do the colors stimulate the 
appetite of the fish by their resemblance 
to the model ? 
There have been devoted much 
thought and speculation to these sub¬ 
jects, but they still remain, more or less, 
in the field of investigation, not of cer¬ 
tainty. The late Henry P. Wells took 
an active interest in this phase of 
angling, and spent much study and 
thought on the subject. But practically 
all of the study made has been spent in 
the effort to ascertain how the artificial 
lure would appear to the human eye. 
There has also been tried the more 
commendable method of opening and ex¬ 
amining the stomachs of trout, when 
caught, to find what their diet at the 
time consisted of. Trout cannot always 
be caught, however, on the fly which 
the angler may have to present; and, 
when they are taken the contents of 
the stomach is usually in such a condi¬ 
tion as to furnish no exact model, in 
good condition, to the fly-tier. An 
angler says that he found “a small, grey 
fly,” or “a little, black fly,” etc. But, 
unless he is a trained entomologist, he 
would be at a loss to produce an artifi¬ 
cial having much resemblance to the 
natural. 
For several years, and from time to 
time, I have been considering this prob¬ 
lem, using information gained from the 
study of trout in captivity. My data is 
based on the feeding habits of at least 
a dozen fish, ranging from two or three 
inches to seven or eight in length. 
Some of these trout were kept in little 
pools near camp and accessible enough 
to permit constant observation; others 
were kept in a large pail, or in a glass 
aquarium; in the last, their movements 
could be clearly discerned, as they first 
quivered their fins, and then shot quickly 
to their food. Several were raised from 
fry to a length of some inches and be¬ 
came so tame as to snatch their food 
from one’s fingers, even jumping from 
the water to do so. After a considerable 
time some individuals would scurry to 
the front of the aquarium whenever any¬ 
body approached and hang with quiver¬ 
ing fins and upturned eyes, expecting 
something eatable to be thrown upon the 
water. 
In fact, one specimen was so excited 
when it saw me coming that it actually 
jumped right over the edge of the 
aquarium nearest me and fell on the 
floor. Of course, it went back promptly. 
So great did the confidence of these fish 
in human nature become, or so great 
was their stupidity, that any small ob- 
By EDWIN T. WHIFFEN 
ject thrown on the water was seized 
and tasted at once. At times if a per¬ 
son looked over into the aquarium the 
fish would come to the surface, seize 
and reject small particles that might be 
floating on the top and then look up 
as if expecting to be fed—at least, any¬ 
thing edible thrown on the surface was 
seized and devoured immediately. 
As a result of these studies, ranging 
over several years and including a dozen 
fish or so, an effort will be made to find 
out how far justified are some of the 
dicta of the fly-fisherman. 
A S to the effect of weather conditions, 
trout kept in an outdoors aquarium 
would furnish no reliable data, except 
during the warmest part of the year. 
The temperature of the w'ater and of 
the air under those conditions would be 
Anglers are often puzzled to know 
just why a certain form of fly ap¬ 
pealed to a trout that had rejected 
all other lures. In this article Mr. 
Whiffen gives our readers the benefit 
of his many experiments made on 
this subject and advances some very 
plausible conjections that will be of 
great interest to fly fishermen. 
so modified by the artificial heat of the 
house in the colder season as to supply 
no accurate parallel to the outside en¬ 
vironment. But many of the trout ex¬ 
perimented upon were constantly out¬ 
doors. So for the purpose their actions 
may be considered a sufficient basis for 
study and comparison with fish in the 
natural environment. It should be noted 
further that these fish became so tame 
as to manifest no fear of a human be¬ 
ing when conditions were ordinary. Of 
course, splashing in the water or ex¬ 
cited motions above it, as thoroughly 
frightened the tame fish as they do wild 
ones. All experiments were tried upon 
our native speckled trout ( Sal-mo fon- 
tinalis). I have never had an oppor¬ 
tunity of studying in captivity the rain¬ 
bow trout (Salmo irideus ) or the brown 
trout(Salmo fario ), though experiments 
on those varieties would undoubtedly 
yield interesting and valuable informa¬ 
tion. 
As to their choices in food there were 
differences noted among the individual 
fish just as among persons. From 
smallest to largest, all were extravagant¬ 
ly fond of angle-worms. As soon as 
the worm touched the water and began 
to sink, squirming as it went, there 
would be a wild rush and the worm 
would be seized and swallowed as 
quickly as possible. 
Frequently this would be the first food 
that a captive specimen would take, as 
they are often shy for the first few 
days, and that in spite of the fact that 
the individual had been caught on that 
kind of bait. Evidently the bait-fisher¬ 
man needs no further recommendation 
as to the taking qualities of this lure 
other than this evidence and his own - 
experience. Yet, in actual experience, 
I knew of one day in August when a 
Red Tag fly secured thirty-nine trout, 
while worm-bait took only seven. Evi¬ 
dently the species has a discriminating 
taste sometimes. 
In the house itself house-flies were 
about the most easily secured food for 
captive trout. If caught and thrown in 
alive, so that they could go buzzing 
around on the surface, they were taken 
when the fish was hungry and had no 
other kind of food offered. If the flies 
were dead when thrown on the water 
they were not often noticed until they 
sank and became mouldy. Often they 
would be seized, alive or dead, but 
ejected as soon as the fish discovered 
what it had taken. 
A large, light-greyish fly, slimmer 
than the house-fly, known locally as the 
deer-fly in the Adirondacks, was a choice 
morsel. An artificial tied after this 
model, with rather long, transparent 
wings, flatwise, would be an effective 
lure for trout, and is, in fact, as various 
grey artificials show. 
Blue-bottle flies received much the 
same treatment. Though they were 
considerably larger and consequently 
more difficult to swallow than the house¬ 
fly, as a rule they were seized at once, 
alive or dead, and strenuously masti¬ 
cated until swallowed. From this I am 
inclined to believe that an accurate copy 
of this insect, with a plump body and 
wings made of fish-scales, tied flat-wise 
and standing out at an angle of about 
45 degrees, would be a very taking lure. 
The so-called blue-bottle of the dealer 
has little resemblance to the insect it¬ 
self. 
Of course I realize that actual prac¬ 
tice might contradict this belief. When 
insects are plentiful on and under the 
water, trout in a natural environment 
have a wide range of choice, and may 
reject for a daintier morsel a form of 
food readily taken in captivity. Ex¬ 
perience hardly confirms that supposi¬ 
tion, however. 
Trout of the size I have had an op¬ 
portunity of studying, up to seven or 
eight inches or so, rarely take cater¬ 
pillars, hairy or hairless, though the 
