Modern Weights and Measurements of Wild Lions

[Pckts]

(02-17-2022, 04:41 PM)LandSeaLion Wrote: So I got around to reading that paper that SpinoRex posted ("Hunting by male lions: ecological influences and socioecological implications" by Funston et al). It's an interesting one! There are some details that I think are important but so far have been overlooked in the discussion. The authors note that the movements of pride males were constrained by the need to patrol the pride territory and scent-mark the boundaries to deter rivals; nomadic males on the other hand, with no territory to maintain, were free to pursue the movements of their favoured prey (buffalo). They also seemed more likely to engage in more risk-taking behaviour. This could explain why the nomadic lions killed this prey at higher frequencies than the territorial males in the study. It's also possible that this is a location-specific phenomenon, which in my view may explain why it contradicts the findings of some other studies (which found that pride males are generally better fed than nomadic males). The local environment, after all, has a big impact on hunting and territorial behaviour.

Quote:Amongst the males, the differences in prey selection,with nonterritorial males catching significantly more buffalo and scavenging less frequently, reflect important social differences between the two groups. Nonterritorial males, with their slightly larger group sizes and freedom to select foraging ranges, preyed on dangerous, but rewarding, buffalo more frequently than territorial males.The latter have to maintain sufficient body mass and condition to ensure their competitiveness in territory defence, and are essentially restricted to foraging within their territorial range. In contrast, nonterritorial males may benefit by ranging more freely in search of buffalo,and thus from eating more than the minimum required amount. In fact, they encountered buffalo more frequently than the other lion group types, suggesting that they were occupying areas where buffalo were likely to been countered. Killing buffalo frequently, and thus eating more, allows for rapid growth and the acquisition of the body size required to challenge for territorial status,provided that their coalition size and experience allow successful hunting of buffalo. Although there was no significant difference in probability of hunting success, nonterritorial males had slightly lower success rates than the other groups (57 versus 72–73%), suggesting less experience, at least initially, in capturing buffalo.

On the topic of food-sharing, interestingly enough, non-territorial males were observed to share food with unrelated males from other coalitions:

Quote:A further aspect of the nonterritorial males’ behaviour was food sharing with other unrelated nonterritorial males. Sharing with unrelated individuals of the same status was never recorded during the study for the other groups. It is, however, known that pride females will occasionally feed on carcasses with other prides (Schaller1972; personal observation in other parts of the KNP). Nonterritorial males, however, shared a relatively large number (26–40%) of their carcasses with other coalitions.This was probably because of their being attracted to large  buffalo kills. On five occasions, more than one coalition of males was observed hunting the same large buffalo herd. Food sharing could also be explained by the reduced likelihood of aggression between equally low-ranking nonterritorial male groups at large carcasses.

Male lions living in prides typically take "the lion's share" and appropriate the carcass for themselves when the prey is small - however, for large prey, they fed together with the rest of the pride:

Quote:Territorial males obtained significantly more meat from each carcass killed by themselves (X +/- SD=38 +/ 17 kg, N =21) than from carcasses that they scavenged (19 +/- 10 kg, N = 23, Mann-Whitney U test: Z = -3.25, P < 0.05). When joining pride females at a kill, territorial males were usually sufficiently dominant to appropriate smaller (<100 kg) carcasses (10 of 13) whereas when feeding on large carcasses (>100 kg, usually adult zebra, wildebeest or buffalo), they were not able to appropriate the entire carcass and fed together with the pride (5 of 6; Fisher’s exact test: chi^2 = 6.11, P < 0.05).

Some more notes on the impact of environment on hunting and territorial behaviour (male lions in plains-like ecosystems did less independent hunting - relying more on lionesses - than male lions in thicker bush, for example):

Quote:The cross-habitat review showed that in open ‘plains-like’ ecosystems adult males tend to be located mostly in the company of pride females (Table 7). We propose three hypotheses that may explain habitat-related differences in male/female associations.

(1) Hunting success. In open areas males have difficulty hunting suitable prey. This is probably because of (a) a lack of cover, as males are more conspicuous and slower than females, (b) all-male groups generally associate in smaller average groups than females do, and group size is an important variable affecting hunting success (Scheel& Packer 1991; Stander & Albon 1993; P. J. Funston, M. G. L. Mills & H. C. Biggs, unpublished data) and © in many areas buffalo are either absent or at low densities. Suitable prey and habitat, that is, buffalo and impala in thick bush, need to be present at sufficiently high densities to allow males to hunt for themselves (P. J. Funston,M. G. L. Mills & H. C. Biggs, unpublished data).

(2) Territory and/or group defence. It is accepted that territorial males primarily defend the territory of the pride, enabling a cohort of their cubs to be reared(Schaller 1972; Bertram 1978; Packer 1986). In open areas, males may defend cubs largely by staying with the females. Visibility over the pride range is not hindered so that (a) males are easily able to detect intruders in their females’ territory when in the company of the females and cubs, and (b) females and their cubs are more easily detected by intruding infanticidal males, necessitating that the males accompany them. In a savanna woodland environment where intruders are less conspicuous it maybe necessary for males to patrol the territory, repelling other males by maintaining the territory through scent marking and roaring. Females and their cubs would also be less easily detected in thicker bush.

(3) Spotted hyaena interrelationships. Cooper (1991)suggested that cooperative defence of carcasses against high density spotted hyaena populations may be a factor influencing lion grouping. In areas where spotted hyaenas occur at much higher densities than lions, they appropriate large amounts of meat from female kills(Schaller 1972; Cooper 1991). When females are outnumbered at a kill by spotted hyaenas by more than four to one, they are unable to defend their kills (Cooper 1991) whereas spotted hyaenas are not able to appropriate kills when territorial males are present (southern Kalahari:Mills 1990; Savuti: Cooper 1991). The kills made by females are vital to territorial males, both in terms of the food acquisition (particularly in open habitats with low buffalo densities) and to provide food for their cubs. Spotted hyaena density relative to that of lions maybe a factor influencing defence of kills, and thus the association of territorial males with pride females,especially in open habitats where carcasses are more easily located.

I hope that is useful! I do recommend reading the discussion in full.

So numerous things to unpack...
First is the difference in feeding on large prey *100kg or more* observations.
 TM were only viewed on 4 carcasses while NTM were viewed on 13 on top of that no matter the Sub Group, all Lions preyed most often on animals less than 100kg. However pride females caught the most substantial number of large species *100kg or more* since Male Lions aren't very successful in preying on Zebra and Wildebeest while pride females are. And since TM Lions scavenged kills much more often from pride females, they also had access Zebra and Wildebeest without expending any energy. On top of that, Males generally only spent time with females when no cubs were present and during that same time they were most likely to scavenge prey. TM's would spend less time with the pride once cubs were born and overall they spent very little time with the pride as a whole.

Next is the amount of meat available per lion is only a calculation not an actual observation and since TM's were seen with less Adult Buffalo throughout the study the calculation was less for them but that's misleading since TM's were seen with less kills period. 

What really stands out is Impala, both TM and NTM would attempt predation on Impala at the same rate when the encountered them but since TM controlled the thick bush habitat they encountered Impala far more often and thus preyed upon them far more. 
Also the hunting technique, living in controlling the thick bush territory allowed the TM to stalk the impala where as the NTM had to chase upon detection.
The NTM's encountered Buffalo more often but no difference in success rate on hunts between groups so that again leads itself to the idea that the NTM are forced to inhabit a more open habitat and Buffalo were their only option. Buffalo hunts also cover a significantly greater distance so this means the Lions would likely expend more energy tracking and hunting buffalo as well as Buffalo being more dangerous prey obviously. 

Next is Hyena, which made up very little observations at kills but when they did show they were least present at Territorial Male kills and most present and NTM kills. 
Hyena #'s only exceeded female #'s at 5 out of 77 kills observed, and never higher than a ration of 3:1 and they showed that 4:1 is needed to usurp a kill from a female, which goes to show their small impact on Lion predation there. Although it will depend on the location.
For instance, Males spent very little time with pride females in general but in areas where Hyena outnumber Lion 6.3:1 *Savuti* TM spent more time with their prides, so in areas with high Hyena density the pride males play much more of a factor in protection than areas where the Lion/Hyena density is low. So most likely E. Africa TM males are the most important since animal/lion/hyena density is the highest on earth. 
This is also implied in the fact that Males NT/TM alike made their own kills much higher there than in other areas.

This limited study also had differences in coalition size, TM's were no more than 2 while NTM's were between 2-4, this could also play a role in prey taken. The Notches are probably a perfect example, their large coalition size and prey availability turned them into Hippo hunters and the largest Lions in the Mara. This could be different in S. Africa where the prey density and habitat is different. 

Like the paper states, there are a significant amount of ecological factors that goes into prey preference. You could make arguments for or against many claims, but nothing I read in this study backs the idea that a TM will have less food intake than a NTM. What I really take away from it is the major differences in lifestyle between the two, it's no doubt easier to be a TM in Kruger than a NTM, which I think most would agree regardless of reading this study or not. Reply