tyger, tyger, stalk and kill

[twoeleven]

last week's science has a couple of papers on the bio-energetics of two species of big cats, cheetahs and pumas. i think a few of y'all might be interested for different reasons. (...and those what interested are but lack access might be visited by the journal fairy.)

science is also running a news story on the papers, but like the papers, it's behind their paywall. some key bits:

The carnivores investigated in the two studies seek prey in very different ways. Pumas are sit-and-wait hunters, whereas cheetahs typically chase their prey at high speeds. The results of the studies should thus help to elucidate the effect of energetic demand on hunting style.

There have been ample studies of the energetics of carnivores. However, most attempts to calculate the energetics of large carnivores have not explicitly determined the specific energy necessary for seeking and subduing prey. Most have relied on estimates of metabolic rates under laboratory conditions (7, 8) or velocities and distances traveled over 24 hours based on telemetry or Global Positioning System data gathered from wild animals with collars (9, 10). Williams et al. and Scantlebury et al. instead used more specialized techniques to measure specifically the energy that a carnivore expends during the critical phases of searching for and subduing prey. The most ingenious was the use by Williams et al. of a new SMART (species movement, acceleration, and radio tracking) collar that differentiated among various activities such as resting, eating, and running. The results help to understand how the two species have evolved to compensate for these high-energy-demand activities and have consequences for the conservation of these species.

Both studies concur that seeking prey is much more energetically costly than subduing the prey. Intuitively, one would think that the extreme physical exertion of chasing and pouncing on prey would far outweigh the searching process. As both studies point out, however, although subduing prey is energy-intensive, the time spent doing this is short. Carnivores either quickly capture their prey or give up. Furthermore, Williams et al. found that pumas adjust their energy investment based on prey size, not overexerting themselves on smaller prey.[...]

Because seeking prey is the more energy-intensive activity, both studies propose that these species have evolved ways of reducing this demand. Pumas can substantially reduce the energy demand of seeking prey with their sit-and-wait approach, as do most felids—except cheetahs. Cheetahs, and probably other carnivores that chase their prey, opt for minimizing the time they are mobile and seeking prey. Scantlebury et al. point out that kleptoparasitism—the theft of prey by other animals, in this case by lions and hyenas—increases how often or how long carnivores such as cheetahs have to seek animals. However, they note that if prey abundance is high, cheetahs can quickly find additional animals to pursue, reducing the impact of kleptoparasitism to an acceptable level.

the cheetah paper mentions that their peak metabolic output -- which they keep up for a few seconds -- is ~120W/kg. for an 80kg slob like me, that would be a ~10kW output. while i should be able to put out more than that for the fraction of a second it would take my muscles to burn through their ATP, i'd probably fall over dead from that sort of sprint. OTOH, my top isn't made out of rubber and my tail isn't made out of springs, which does give the cheetah a slight advantage.