52 IOWA STUDIES IN NATURAL HISTORY 
by following bits of meat or other small objects which were 
moved about in the aquarium. 
A study of the behavior of the hungry animals in the pres- 
ence of food or other objects which stimulate their interest, re- 
veals at least two distinct reactions. They first approach, then 
seize or attempt to seize an object. If the object is within easy 
reach an attempt may be made to seize it without any appar- 
ent preceding movement. In his study of the feeding reactions 
of the spotted newt (Diemyctylus Coteecany Copeland (713)? 
described an ‘‘approaching,’’ a ‘‘nosing,’’ and a ‘‘seizing”’ 
action. Following Copeland, we will designate the movement 
toward the object the ‘‘approaching reaction’’ and the attempt 
to seize it the ‘‘seizing reaction.’? We were unable to recog- 
nize any reaction of the larvae of Ambystoma tigrinum which 
corresponds to the ‘‘nosing reaction’’ of Diemyctylus virides- 
cens described by Copeland. 
When a bit of meat held with forceps or probe, or suspended 
by a thread, is moved about in the water in the presence of the 
hungry animals it soon attracts their attention. As soon as 
one of the animals discovers and pursues it, others near by are 
attracted and pursue it also. If any of them approach it suf- 
ficiently closely they seize or attempt to seize it. If a small in- 
edible object is presented in the same way, the hungry animals 
react essentially in the same manner. Obviously, the stimuli 
which play the major part in these responses are received 
through the sense of sight. 
When a bit of meat is held quietly in the water, care being 
taken that the animals do not observe the movements involved 
in bringing it into position, the hungry larvae respond less 
promptly. However, in a relatively short time one or more 
of the animals are attracted, approach, and seize or attempt to 
seize it. It is not apparent in many instances whether the 
meat is detected by the olfactory sense or by the sense of sight. 
The normal movements of the animals in the aquarium may 
bring the meat into the field of vision of some of them before 
they are attracted by its odor. As soon as one or more of the 
animals approach the meat others are attracted by their move- 
1Copeland, M. The olfactory reactions of the spotted newt, Diemyctylus virid- 
. escens (Rafinesque)—Jour. An. Behavior 3: 260-273. 1913. 
