An Exploratory Study into the Influence of Sex on Body Measurements, Carcass Weights and Meat Yields of Giraffe (Giraffa camelopardalis angolensis)

Various body measurements and commercial carcass yields of relatively young (2½–6 yrs old) giraffe (Giraffa camelopardalis angolensis) were investigated to quantify the effect of sex there upon. Eight male and eight female giraffe were culled by standard practice in Namibia, where body and horn measurements were taken, before the carcasses were dressed. There were no significant differences between the mean dead weights of the two sexes (bulls = 691.1 kg; cows = 636.5 kg; p = 0.096), the only body measurements found to differ significantly were those of the forelegs, with the shoulder to hoof (p = 0.046) and the knee to hoof (p = 0.025) both being significantly longer in the bulls. The horn measurements were all found to be significantly larger in the bulls than the cows even at this young age. The neck weight as a percentage of the carcass weight was found to be significantly heavier for the bulls compared to the cows, however, the back percentage values were significantly heavier in the cows than the bulls. There was a strong positive correlation between the body weight and most of the body lengths, as well as between most of the individual body measurements. The giraffe used had an average age of 3.7 years old, and had therefore not yet reached their growth plateau, which may be why sex had no influence on most of the body measurements recorded.

Antitypes, Ancestors, and the Origin of Modern Giraffes

Against the odds, over a period of 8 million years the genetic material in small gazelle-like Canthumerycids transformed by natural selection into modern long-legged, long-necked giraffes, Giraffa camelopardalis. How did that happen? The 8 million-year-long evolutionary gap between Canthumerycids and giraffes, during which the astonishing morphophysiological changes occurred, is filled by three ancestral species of Paleotragine giraffids—Giraffokeryx, Paleotragus, and Samotherium—that lived in southern central Europe, with each making small but significant evolutionary contributions. While all had elongated necks, their necks were never more than half the length of modern giraffes. All, though, had long legs. Long necks arose in Bohlinia, a unique species that evolved from the Paleotragine genetic pool. Bohlinia migrated to Asia and gave rise to Indian and Chinese giraffes, and also into North Africa. Relatively quickly the Indo-Asian giraffes became extinct. In Africa the giraffe lineage that produced modern giraffes began with the evolution of Giraffa jumae from Bohlinia about 6 million years ago. G. jumae was the origin of three ancestors of modern giraffes—G. stillei, G. gracilis, and G. pygmaea—that made their appearance in East Africa around 3 million years ago. Their appearance then was a consequence of major episodes of climate change. From their genetic pool, modern giraffes, G. camelopardalis, emerged 1 million years ago.

What’s in a Name?

The modern scientific name of giraffes is Giraffa camelopardalis, given to the species by Mathurin Brisson and Carl Linnaeus in the eighteenth century. At that time a single species was thought to exist, but it soon became apparent that depending on where they lived in Africa giraffes had different skin markings and different “horns.” Thus the idea arose that there were more than one species, or if just one species then there were several different subspecies. Investigation of these two possibilities has depended partly on analysis of external characteristics, but mostly on the study of mitochondrial and nuclear DNA to establish if geographical distribution is associated with distinct genetic differences. These studies have indicated that there may be six separate species or four or three. However, as each of the variants can interbreed, genetic differences thus far have not resulted in reproductive isolation and the overall conclusion must be that there is one species with regional variants/subspecies that can be genetically distinct.

Microbiome Analysis Reveals the Dynamic Alternations in Gut Microbiota of Diarrheal Giraffa camelopardalis

The ruminant gut microbial community's importance has been widely acknowledged due to its positive roles in physiology, metabolism, and health maintenance. Diarrhea has been demonstrated to cause adverse effects on gastrointestinal health and intestinal microecosystem, but studies regarding diarrheal influence on gut microbiota in Giraffa camelopardalis have been insufficient to date. Here, this study was performed to investigate and compare gut microbial composition and variability between healthy and diarrheic G. camelopardalis. The results showed that the gut microbial community of diarrheal G. camelopardalis displayed a significant decrease in alpha diversity, accompanied by distinct alterations in taxonomic compositions. Bacterial taxonomic analysis indicated that the dominant bacterial phyla (Proteobacteria, Bacteroidetes, and Firmicutes) and genera (Escherichia Shigella and Acinetobacter) of both groups were the same but different in relative abundance. Specifically, the proportion of Proteobacteria in the diarrheal G. camelopardalis was increased as compared with healthy populations, whereas Bacteroidetes, Firmicutes, Tenericutes, and Spirochaetes were significantly decreased. Moreover, the relative abundance of one bacterial genus (Comamonas) dramatically increased in diarrheic G. camelopardalis, whereas the relative richness of 18 bacterial genera decreased compared with healthy populations. Among them, two bacterial genera (Ruminiclostridium_5 and Blautia) cannot be detected in the gut bacterial community of diarrheal G. camelopardalis. In summary, this study demonstrated that diarrhea could significantly change the gut microbial composition and diversity in G. camelopardalis by increasing the proportion of pathogenic to beneficial bacteria. Moreover, this study first characterized the distribution of gut microbial communities in G. camelopardalis with different health states. It contributed to providing a theoretical basis for establishing a prevention and treatment system for G. camelopardalis diarrhea.