412 POPULATIONS 



Unlike proto-cooperative phases of ani- 

 mal aggregations, organizational aspects 

 may involve definite conflict— often severe 

 fighting— between members of a contact 

 pair. This is particularly true for the hold- 

 ing of territories and the maintenance of 

 status in a social hierarchy. In both these 

 relationships, group organization grows out 

 of a series of pair conflicts even within the 

 Umits of a more or less closely knit group, 

 rather than from mass encounters. Leader- 

 ship sometimes devolves on the most potent 

 fighter in the group. 



Intraspecies organizational struggles ap- 

 pear later in the evolutionary series than 

 does primitive, automatic proto-coopera- 

 tion. It is made possible, in part, by the 

 presence of natural mutualism within the 

 species, and by group-oriented behavior 

 which, together with environmental gradi- 

 ents, lead to the formation of aggregations. 

 Only animals that are somewhat aggregated 

 can become organized. 



TERRITORY* 



Territoriality includes homing or the de- 

 fense of a given area, or both. Homing re- 

 actions are concerned with an animal's be- 

 coming so adjusted to a specific area that 

 returns are made, perhaps to the precise 

 spot, when activities or environmental ac- 

 cidents cause removal. The distance 

 covered in the return may be only a few 

 millimeters or centimeters in certain mol- 

 lusks. Homing pigeons may return for 

 miles, and displaced men often travel no- 

 table distances. Insects give essentially 

 similar reactions under a variety of condi- 

 tions. 



Homing territories in man are based on 

 preferences that result from learned be- 

 havior. They may be similarly established, 

 to a greater or less degree, by other ani- 

 mals. "Preference" territories are not neces- 

 sarily defended, although they may be. De- 

 fense of boundaries occurs to such an ex- 

 tent among territorial birds that ornitholo- 

 gists define bird territory as a defended 



"* We have read much of the extensive 

 literature on territoriality in animals and present 

 the following account as a generalized sum- 

 mary without careful documentation for each 

 statement. Initiated students will recognize, as 

 do we, our indebtedness to the competent 

 scholarship of Margaret M. Nice (1933, 1937, 

 1939, 1941, 1943). 



area. Defense against territorial invasion is 

 well developed by many fishes, lizards, and 

 mammals as well as by man. It is also 

 known for the fiddler crab Uca (Crane, 

 1941). Territoriality is based both on a 

 positive reaction to a given space and, 

 within that, often, on a negative reaction 

 to invaders of the same species, except for 

 a mate or mates. 



We know more about the territorial or- 

 ganizations of birds than that of most non- 

 human groups. Birds show the following 

 types of territories: 



1. Mating and nesting combined with 

 space in which to collect food during 

 the breeding season 



2. Mating and nesting with food col- 

 lected elsewhere 



3. Mating station only 



4. Nesting region only: 



a. Sohtary individuals 



b. Colonial birds 



5. Nonbreeding territories including: 



a. Roosting territories 



b. Feeding territories 



Varied types of territorial defense are 

 known among birds when "any defended 

 area" is regarded as being a "territory." Al- 

 though the variations are great, especially 

 when different species are considered, cer- 

 tain general rules can be recognized: Males 

 are more active than females in maintain- 

 ing territories, and they are most active 

 during or near the breeding season. Not all 

 species of birds maintain territories, and 

 of those that do, unmated males may or 

 may not defend permanent holdings. Some 

 birds remain territorial during the winter, 

 although many do not. Often the female 

 does not defend the boundaries kept by her 

 mate, though she may do so; in general, 

 female territorial behavior is much more 

 varied than is that shown by males. Some 

 flocks hold and defend definite areas, 

 others do not; when held, a flock territory 

 may be subdivided or remain a group-de- 

 fended unit. 



Territories tend to be larger when popu- 

 lation pressure is low and to be compressed 

 when more nesting birds are present in the 

 area. The amount of space defended also 

 depends, in part, on the fighting ability 

 and the aggressiveness of the male; its lo- 

 cation is related both to date of establish- 



