Imagine you are a lowly ungulate living on the harsh plains of the Serengeti. You are a delicious meal on legs to the many carnivores that share your habitat. When you notice a predator your natural reaction is to flee. However, evolution has provided you with another option. You leap into the air, all four feet leaving the ground in an exaggerated and highly visible display. The predator sees you and assesses your physical condition. Hopefully it decides that you are too fit and too much work to try to catch.
Although a seemingly bizarre interspecies communication, stotting is advantageous to a svelte Thomson’s gazelle because it is an honest signal of its physical capabilities. If it weren’t, the behavior would soon have been selected against. Researchers have found that the more stots a gazelle makes in the presence of a predator, the less likely it is to be selected by that predator and chased (thus preserving its energy stores), and if it is selected, the more likely it is to escape. Therefore it is also beneficial for predators to read and understand this signal so that they don’t waste their time and energy chasing gazelles that can outrun them.
Besides showing off their physical capabilities, another interesting hypothesis is that stotting is used by gazelles when they notice a predator stalking them to convey that the predator has lost the element of surprise. However, researchers have not observed a correlation between stotting rate or height and the selection of the prey when gazelles are approached by a stalking animal such as a cheetah. It is used much more often in the presence of “coursers”, animals such as wild dogs and hyenas that rely on their stamina to run down prey, compared to “stalkers” which use camouflage and quick bursts of speed. It appears that coursers understand the stotting signal but stalkers do not, and choose their prey before they attack regardless of stotting.
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Photo credit: Gerald Hinde/Gallo Images/Getty Images
Posted by Alex Sprague
Response to comments:
Thank you all for the comments! A little further research in response to everyone’s queries and hypotheses yielded some interesting information. It seems that the exact reason gazelles stot is actually very unclear among animal behaviorists. A different article I perused suggested that stotting serves no function related to predator deterrence. The paper argues that the main function of stotting is for young gazelles to convey to their mothers that they are in need of defense. The paper also argues that a young gazelle stotting while being chased by a cheetah will escape more often than one that doesn’t. This doesn’t really match up with other information and articles about stotting that claim it is used to deter predators from beginning an attack, and it appears that there is no conclusive understanding of this interesting behavior.
What an unusual form of communication! Do you think this behavior could also be used to warn other Gazelles that a predator has been sighted?
ReplyDeleteAbbie Lamarre-DeJesus
That is really cool..Do you know how high they leap on average? Also if this is selected for..would it be possible that there are more coursers in the habitat than stalkers? If there were more, that would explain why this strategy works.
ReplyDelete-Katie Cyr
How successful are stalkers when they attack gazelles? Is it possible that they may understand the signal and the gazelle’s attempts to display its strength, but they just ignore it? If they are very good at capturing gazelles, then maybe they don’t need to worry about selecting weaker prey.
ReplyDeletePosted by Katie Kalutkiewicz
I find this to be very interesting both on the gazelle and lion's part. Lion's must be opportunistic hunters if they see a healthy gazelle and would rather prey on a less healthy one. My only question on the lions part would be is there a difference in the healthy and unhealthy gazelle as a meal. Is there less nutritional value in an older unhealthier gazelle than there is a young healthy one? This also goes to show you how the gazelles have kept up with the evolutionary arms race between themselves and the Lions. Gazelles evolved tremendous speed and agility to escape being predated while Lions evolved unbelievable hunting skills and dominant power.
ReplyDeletePatrick Salome
I actually knew about this, although I didn't really think about it. There's got to be an advantage to this signaling behavior. Maybe if the study was from the predators view from young to adulthood, so maybe there's a learning curve where the predator finally understands the signal. Also it would make sense that stalkers are not intended receivers, since the point of stalking is not to be caught. I am guessing that stotting was more beneficial because the major predators are not lions/leopards (i.e. the stalkers) but hyenas and wild dogs who are the coursers. Does that mean these gazelles are the main diets of stalkers rather than coursers? Would it possibly mean that stotting is then a form to deter one type of predator?
ReplyDeletePosted by Leona Chan
Intersting. It makes sense that stotting would be a good way to display the animals physical fitness.
ReplyDeleteStalking predators generally depend on being hidden and the element of surprise so stotting is a way for the gazelle to let the predator know that it's been spotted and will no longer have a good chance of killing it, which usually deters the predator from killing it. This might be another benefit to stotting which helped it to evolve.
-Meghan Nichols