Detecting Genetic Drift Versus Selection in Human Evolution, Essay Example

New evidence on the tool-assisted hunting exhibited by chimpanzees (Pan troglodytes verus) in a savannah habitat at Fongoli, Sénégal was a 2015 study conducted by Pruetz et al. (Pruetz et al. 2015). The authors aimed to determine whether use of tools among chimpanzees is related to the savannah environment that they inhabited, as well as whether there were sex differences in terms of tool use as well as age-sex class differences in hunting behavior. A comparison between a group that used tools in one location and a group that did not use tools in a second location were also compared. As such, this information was collected with the purpose of describing behaviors and tool use among chimpanzees.

The research ultimately demonstrated that adult male chimpanzees are more likely to be hunters, and they hunt by hand (Pruetz et al. 2015). However, Savannah chimpanzees use tools to hunt pray, which is a behavior that is similar to human hunting. This is distinct from other chimpanzee groups. The male chimpanzees were found to use tools in most cases, although tools were used as frequently as the authors had expected (Pruetz et al. 2015). Females were found to use tools in a majority of the cases in which they were observed hunting. Based on this evidence, the authors concluded that early humans likely used tools in this manner to hunt their pray (Pruetz et al. 2015). In addition, it is thought that social tolerance that was present among the chimpanzees that used tools contributed to their ability to coordinate the use of this technology to improve their likelihood of survival.

Overview of the Research

Methodology

The researchers aimed to observe the Fongoli chimpanzee community to collect information about hunting behavior both with and without the use of tools (Pruetz et al. 2015). This community is located in a savannah environment, where there is woodlands, forests, grasslands, and bamboo (Pruetz et al. 2015). Hunting bouts were conceptually defined as the capture of intact pray, and different categories were assigned to these cases: capture that was visually observed, capture out of sight that includes evidence of a successful hunt, and possession, in which the actual capture was not observed (Pruetz et al. 2015). This enables the team to sort their data more readily into one of these three groups as their observations are collected. When observers noted that the chimpanzees were using tools to conduct their hunt, the observer moved within 20 m of the hunting chimpanzee (Pruetz et al. 2015). The outcomes of success were similarly noted for this method (Pruetz et al. 2015).

Findings

The authors observed a total of 99 hunting cases, which included hunting with the use of tools as well as hunting without the use of tools (Pruetz et al. 2015). Females were responsible for 30% of the observed hunting cases, while the other 70% was carried out by males (Pruetz et al. 2015). In 21% of cases, the chimpanzees made the use of tools to assist their hunt. In addition, 40% of successful hunts were conducted by females (Pruetz et al. 2015). The most successful hunter was the lowest ranking male, who was also the oldest of the group. Two alpha males were also considered to be the best hunters, although one alpha only caught prey once (Pruetz et al. 2015). Ultimately, this evidence effectively summarizes the hunting patterns that were present in the hunting scenarios performed by the Fongoli chimpanzees.

Interpretations

The fact that the Fongoli chimpanzees use tools is meaningful because this is the only non-human population that has been known to do so (Pruetz et al. 2015). The use of tools was more closely affiliated with female hunting than male, and the use of these tools likely contributed to the success of the hunt. The savannah environment likely contributed to the role of tools in the lives of the Fongoli chimpanzees because they have the raw materials that are needed to create usable tools for hunting. Chimpanzees in other locations likely have the ability to create these tools if they were raised in an environment that was similar as the Fongoli chimpanzees. A similar trend was seen among tool use in Bonobos, since mostly females tend to use weapons as well (Pruetz et al. 2015).

Significance

The researchers claim that it would be advantageous to use our present understanding of chimpanzee hunting behavior and tool use to further evaluate the hunting patterns that are exhibited by female chimpanzees. In particular, it is thought that female feeding and hunting behavior may be different from these behaviors when exhibited by males of the species (Hughes et al. 2005). It is likewise valuable to compare the similarities of these gender differences among chimpanzees to understand more about these same differences among male and female humans, given the close evolutionary relationship between chimpanzees and humans.

Discussion of Positive Aspects

There was no officially claimed hypothesis, but one would generally expect males to be the better hunters. However, females were also good performers in terms of hunting Pruetz et al. 2015). It is expected that the findings generally contradicted the expectations, which is a positive because it revealed that hunting patterns are not necessarily straight forward. For example, while one would expect an alpha male to be among the best hunters, this was not always the case. This helps demonstrate that there are some additional social rules that guide the practices of the chimpanzees. An additional benefit is that the research process was adequate in terms of creating a design that addressed all of the research questioned posed. The authors also posed an interesting case example of a group of non-humans that are exhibiting a human behavior because this could provide us with important information about human evolution (Ackermann and Cheverud 2004).

Discussion of Negative Aspects

The author notes the number of hunts that were observed, but not the duration of time over which the hunts occurred (Pruetz et al. 2015). It is reasonable to consider that there may be some variance in hunting behavior and success of hunting over time, but this possible bias cannot be accounted for because this information is not reported. Other than this key factor, the authors appear to have been thorough in accounting for factors that could potentially impact the reliability and the validity of the research (Healy and Perry 2000).

Conclusion

Overall, the purpose of the research conducted by Pruetz et al. (2015) was to summarize the hunting behaviors of the Fongoli chimpanzees. This group is distinct compared to other chimpanzee populations due to their ability to use tools to hunt, which is remarkable because this group is the only known non-human group to have this ability and to apply it as a survival technique.

It was determined that males are more likely to hunt than females in general, but females are more likely to make use of tools they created as an aid for hunting. In addition, the hunting success rate of females was just lower than that of males. The authors concluded that there is more to learn about the hunting behaviors of female chimpanzees, since most of the literature presently available describes the hunting behaviors of males.

This research helps contribute to our present understanding of human kind. In particular, human males are more likely to engage in hunting behaviors compared to women. Many of the recent mass shooting have been perpetrated by men. On the other hand, it also shows that females may exhibit hunting behaviors less of the time, but they still participate in them. Male chimpanzees are less likely to use weapons when hunting, which correlates with the fact that men are more likely to get into physical fights with their fists, since this does not make the use of a women. Many human women would also feel more comfortable using a weapon in a fight, and certainly to hunt something. As such, this demonstrates that gendered differences that are typically attributed to humans could also be observed among chimpanzees. This demonstrates that humans and chimpanzees have even more similarities than originally thought.

Bibliography

Ackermann, R. R., and J. M. Cheverud. 2004. “Detecting Genetic Drift Versus Selection In Human Evolution”. Proceedings Of The National Academy Of Sciences 101 (52): 17946-17951. doi:10.1073/pnas.0405919102.

Healy, Marilyn, and Chad Perry. 2000. “Comprehensive Criteria To Judge Validity And Reliability Of Qualitative Research Within The Realism Paradigm”. Qualitative Market Research: An International Journal 3 (3): 118-126. doi:10.1108/13522750010333861.

Hughes, Jennifer F., Helen Skaletsky, Tatyana Pyntikova, Patrick J. Minx, Tina Graves, Steve Rozen, Richard K. Wilson, and David C. Page. 2005. “Conservation Of Y-Linked Genes During Human Evolution Revealed By Comparative Sequencing In Chimpanzee”. Nature437 (7055): 100-103. doi:10.1038/nature04101.

Pruetz, J. D., P. Bertolani, K. B. Ontl, S. Lindshield, M. Shelley, and E. G. Wessling. 2015. “New Evidence On The Tool-Assisted Hunting Exhibited By Chimpanzees (Pan Troglodytes Verus) In A Savannah Habitat At Fongoli, Senegal”. Royal Society Open Science 2 (4): 140507-140507. doi:10.1098/rsos.140507.