How the Horned Lizard Got Its Horns?

Introduction

The theory of evolution by Charles Darwin gave numerous principles regarding the various reasons certain being intuitively adapt to its surroundings. The study covered the topic on the possible correlation on the growing of horns to the presumed defense function of these horned lizards against their marauders. These also show the process of natural selection being present in the wild particularly in the shrikes-horned lizards’ relationship.

Hypothesis

Predation is the main factor on how the lizards got their horns developed. These are mainly their defensive mechanism against their predators in the wild.

Experimental Set-Up

Flat-tailed horned lizards were the main subjects of this study. 29 skulls of shrike-killed lizards and 155 heads of live lizards were gathered and compared the parietal and squamosal horn lengths. Standardized statistical measurements were also used (standard deviation and median) as means of analyzing the data collected.

Results

The average parietal and squamosal lengths of the live horned lizards compared to that of lizards killed by loggerhead shrikes were 10% and 10.4% longer, respectively. The results also show that length of parietal horns implies less attraction for the predators than that of squamosal horn lengths. Indications of further development of these horns is possible

within the next generations of these species since the numerical values measured in the study is considerably less than that of the other studies conducted.

Conclusion

The study associated the statistical form of selection to a specific agent accountable to the observed continued existence of certain species. The study did not provide other possible factors affecting the horn size of the horned lizards but nonetheless, showed that defense against predation brought about by logger head shrikes is one aspect driving the horn development in some species of horned lizards.

Reference

Young, Kevin V., Brodie, Edmund Jr., D., Brodie, Edmund III, D.,  How the Horned Lizards Got its Horns. Science 304:65