Question

Suppose you are a graduate student studying primate sociality (the area that examines reasons why primates live in groups). You observed a group of howler monkeys in northern Argentina to determine whether competition over resources or predation avoidance is the primary factor favoring group living. (a) First, describe both the Resource Defense Model and the Predation Avoidance Model. (b) One piece of data you obtained was that larger howler groups had larger territories. If the howlers formed groups for resource defense, what would be the expected relationship between group size and territory size? [Your answer to this question should be something like, "As groups size increases, territory size is expected to (increase, decrease, stay the same."] Explain how this data supports the Resource Defense Model. (c) Another piece of data you obtained was that predation rates were the same regardless if howlers lived in large or in small groups. If howlers formed groups to avoid getting eaten, what would be the expected relationship be- tween group size and predation rates? Explain why this data contradicts the Predation Avoidance Model.

Answer 1

1. Resource Defense Model: This can be explained in terms of defense, aggressiveness and density of species. When the density of animals scavenging for a part or resource of any food resource upsurges, there is increase in the fierceness which is related with depending the resource or the foraging part to derive the sustenance When the density is low, there is less fierceness or aggressiveness seen as equated to that of the fact mentioned above. In other words, there is no intra-species interaction which in turn permits equal credit to consuming the resource, nevertheless when the density increases, there will be increase in amount of conflicts within the affiliates of the species. This results in the origin group finder to display the fierceness or aggressiveness nature in order to trace and eradicate the other affiliates or members away from the reserve Cases, when there is a dissimilar species member foraging for the resource, this would in turn show ample differences in rivalry which would affect the welfares allied with defending the resource. Predation Avoidance Model: This Model or theory fundamentally outlines a specific strategy implemented either in the form of group or as an individual to avoid themselves from effective predation Greater the group size in most of the cases offers more safety due to decrease in time associated with observance or protecting the group. This can be stated as an advantage in terms of existence of group members who are better at recognizing locations occupied by predators and at the same time this social alliance may also lessen the rate of related predation. Living in group but existence of small number may upsurge the chances of effective predation.