Grazing Behavior of the Giraffe in Hwange National Park, Zimbabwe
As mentioned in a previous post, acacia
leaves make up a majority of a giraffe’s diet. Therefore, giraffes are
typically classified solely as browsers. “Browsing” is foraging behavior that
occurs when a giraffe stands upright, like when eating leaves from a tree
(Seeber 248). However, studies
show that giraffes sometimes feed on grass and herbs at ground level, which
requires them to assume the ‘drinking position’ where their front legs are
spread apart so their heads can reach the ground. Peter A. Seeber and his team
of researchers observed giraffe feeding behavior (for a total of 188 hours)
from March to May 2011 in Hwange National Park, located in Zimbabwe (247). The
team investigated how often grazing is part of giraffes’ feeding behavior, and
recorded the number of grazing events observed as well as the duration of the
grazing behavior.
Giraffe in Hwange National Park, Zimbabwe
Thirty-one instances of grazing occurred
for a total of 174 minutes of grazing, which made up 1.5% of the total
observation time (248). Interestingly, giraffes that did graze were almost
always in groups, perhaps because the ‘drinking position’ makes giraffes
vulnerable to predators. Seeber’s research illustrates that although not a
primary activity, grazing does occur in a “nutrient-poor environment” like the
Hwange National Park (247). Upon reviewing their results, the researchers
concluded, “the function of feeding on herbs during the dry season is not
principally to supplement protein/energy intake, but rather to access other
nutritional factors not currently present in sufficient amounts in browse…
because the herb layer sometimes has more available micronutrients than browse”
(249). Further research about the micronutrient content in plants would
supplement the research conducted at Hwange National Park.
Giraffe grazing in 'drinking position'
Seeber, Peter A.,
Honestly T. Ndlovu, Patrick Duncan, and Andre Ganswindt. "Grazing Behaviour
of the Giraffe in Hwange
National Park, Zimbabwe." African Journal of Ecology
50.2 (2012): 247-50. Wiley Online Library. Web. 25 Apr. 2012.
<http://0-onlinelibrary.wiley.com.sally.sandiego.edu/doi/10.1111/j.13652028.2011.01314.x/abstract;jsessionid=
8F1D66A9F273D7BA85E8F2E8453218CC.d03t03>.
This is really interesting! I always assumed giraffes only bent over to drink water! I wonder grazing in the drinking position is such a small part of their dietary behavior? It is interesting to consider that they only graze when the environment is nutrient poor; it seems like they would always want the different nutrients they can gain from both grazing and browsing! Perhaps the lack of need to graze developed over time because of the danger of being bent over, maybe all the giraffes who needed the nutrients found in grazing were killed off! This is an interesting evolutionary idea!
ReplyDeleteI wonder if there isn't as much nutrients in the grass. This is interesting seeing as giraffes don't really graze, according to this article. Maybe the reason they graze when the environment is nutrient low is because if the grass itself is not high in nutrients, it would be safe to assume that the trees would not have as much (because they get their nutrients from the ground). It also makes sense that they graze in groups. Don't giraffes normally feed in groups anyway?
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