Monday, February 1, 2016

The Mara's Mighty Hunters

While driving home from obs one fine January evening, we were startled by a flurry of motion in the road – a black-backed jackal in hot pursuit of a springhare. We stopped the car to watch the lightning-fast chase. One wrong step from the hare gave the jackal the opening he needed; in the blink of an eye he’d scooped up his prize in his jaws and trotted off into the grass to enjoy his freshly-caught dinner.

The thrill of watching the hunt got me wondering about the other hunters who inhabit the Mara. Almost every prey animal in this vast grassland is built for incredible speed, so how do the predators who live here manage to keep up? Hunting strategies vary widely by species, region and prey, but I’ll cover some of the most common techniques for the Mara’s greatest hunters.


I’ll start with the critter that sparked my interest: the black-backed jackal. Jackals are opportunistic omnivores, which essentially means they will eat anything they can get their jaws around. This covers everything from insects, reptiles and rodents, all the way up to fully grown impala. For smaller prey, like rodents and the unfortunate hare whose demise we witnessed, jackals use their impressive agility to catch and subdue their food. For larger prey like gazelles and impala, jackals switch to a harrying technique to compensate for their small size – harassing an animal until it’s too tired to fight back, then taking it down with bites to the throat or stomach. Though they don’t hunt nearly as much as the obligate carnivores (animals which are only capable of eating meat) of the Mara, jackals have a hunting prowess all out of proportion with their size.


Like the jackal, leopards have a size disadvantage to many of the species they choose to prey upon. Weighing in at only 66-176lbs, leopards are outweighed by some of the larger antelopes that make up their diet. They make up for this with unparalleled stealth and jaw strength. Leopards stalk their prey by night, choosing to pounce at close range from the ground or dropping from trees onto their unsuspecting target. As we were lucky enough to witness, they can kill with blinding speed, using powerful jaws to crush their prey’s throat. Unfortunately, leopards are frequent victims of prey-theft by lions and hyenas due to their small size. To prevent this, they commonly stash carcasses in trees. If you’re wondering how much strength that would take, try dragging something that weighs more than you do backwards up a tree using only your mouth, and let me know how it goes.


Don’t tell the hyenas, but cheetahs are my personal favorite Mara hunter. Unmatched in elegance and, of course, in speed, the cheetah has definitely earned its place as the world’s fastest land mammal. Different sources give different numbers, but most experts I could find agree these lovely cats can break at least 60mph in a dead sprint. Everything about the cheetah is built for speed. Their spine is extra flexible to allow their legs to reach huge distances per stride. Their claws have lost the ability to retract in favor of acting like sprinter’s cleats to give them greater grip on the ground. Even their tails are adapted for use as a counterbalance, allowing cheetahs to cancel forward momentum in order to change directions more quickly in the heat of a chase. All of these finely-tuned adaptations pay off: cheetahs have a nearly unheard-of hunting success rate of 50%. The much-lauded lion has a success rate of only 17-19% when hunting alone, or around 30% when hunting in groups. However, there are drawbacks to their speedy build. Cheetahs are comparatively small and fragile, which mean as many as half of their successful kills are stolen by lions and hyenas.


They may not be the most successful, but lions are certainly the biggest and the baddest of the Mara’s hunters. Some males in East Africa have reached sizes of around 390lbs. Their impressive bulk means they can’t keep up with agile antelope in a test of speed, so they must rely on stealth instead. Lions hunting on their own will stalk their prey, taking advantage of the Mara’s tall grasses to hide them until they are within pouncing distance. Lions hunting in groups can get a little fancier, and employ tactics where one lion lies in wait while others drive the prey into an ambush. Though they have the reputation as one of the world’s mightiest hunters, lions actually prefer to scavenge whenever possible. They use their strength and numbers to shoo other predators off their kills and take the food for themselves. Typically, only a group of hyenas are capable of defending themselves at carcasses when lions come calling.


Last, but certainly not least, our own beloved spotted hyenas. Hyenas are possibly the world’s most infamous scavengers and carcass thieves, but it is a reputation that is only partially deserved. Hyenas do indeed scavenge and steal, but they are excellent hunters in their own right, killing up to 90% of their own food. Rather than employing speed and stealth like most of the Mara’s predators, hyenas rely on their powers of endurance. Hyenas are built to run at a steady lope for many kilometers, wearing their prey down until it is incapable of running any farther before eating it alive.

References:

Holekamp, K. E., Smale, L., Berg, R. and Cooper, S. M. (1997), Hunting rates and hunting success in the spotted hyena (Crocuta crocuta). Journal of Zoology, 242: 1–15. doi:10.1111/j.1469-7998.1997.tb02925.x

Kamler, J., Foght, J., & Collins, K. Single black‐backed jackal (Canis mesomelas) kills adult impala (Aepyceros melampus). African Journal of Ecology 09/2009; 48(3):847 - 848. DOI: 10.1111/j.1365-2028.2009.01173.x

http://www.sanbi.org/creature/black-backed-jackal

http://animals.nationalgeographic.com/animals/mammals/leopard/

http://www.cheetah.co.za/c_info.html

https://lionalert.org/page/predatory-behaviour

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