There is a world somewhere between reality and fiction. Although ignored by many, it is very real and so are those living in it. This forum is about the natural world. Here, wild animals will be heard and respected. The forum offers a glimpse into an unknown world as well as a room with a view on the present and the future. Anyone able to speak on behalf of those living in the emerald forest and the deep blue sea is invited to join.
Predatory behavior and kill rate of a female jaguar (Panthera onca) on cattle
By Wlodzimierz Jedrzejewski, Hugo Cerda, Ángel Viloria, Jose Gertrudes Gamarra & Krzysztof Schmidt.
Abstract:
Killing behavior and consumption rate are important components that determine the final preda-tion rate. We studied the predatory behavior of a female jaguar with one offspring in Hato Piñero in Venezuelan Los Llanos. Seven carcasses of freshly killed calves were found over a period of 9 days. Automatic video recording was used to document the jaguar’s behavior. Our study revealed a detailed, repetitive sequence of female jaguar behavior while hunting for calves. The sequence started with the female killing a calf by biting through the skull or neck, then she dragged the carcass to concealment, evis-cerated it and left it concealed; then, the next evening, the female returned with its cub, fed intermittently for a total time of about 90 min while in the meantime it hunted for new prey. All this sequence seems to have a highly adap-tive significance for a female jaguar rearing cubs and utilizing large prey. During the short period of our obser-vations, the estimated kill rate of the female jaguar with one offspring was from 0.67 to 1 calf per day. Proper cattle management is necessary to avoid high losses of calves from predation by jaguars.
Depredation of livestock by jaguars (Panthera onca Linnaeus 1758) often results in the retaliatory killing of this predator by farmers, and is thus regarded as one of the most important reasons behind the decline of the species range (Rabinowitz 1986, Quigley and Crawshaw 1992, Gonzalez-Fernandez 1995, Hoogesteijn et al. 2002, Silveira et al. 2008, Jedrzejewski et al. 2011). Therefore, any information that can increase our understanding of the mechanisms deter-mining the jaguar predation rate of livestock is important, as it can help in developing methods to minimize the conflict. Killing behavior and consumption rate are important components of the predation process.
In this article, we report on observations of the killing and foraging behavior of an adult female jaguar with a half-grown cub in a cattle ranch in Venezuela. We also attempted to estimate her killing rate. The study was conducted on a private ranch, “Hato Piñero” (8°56′ N, 68°04′ W), located in the region of Los Llanos in the Cojedes state of Venezuela, in the hills of Macizo de El Baul and plains, between the rivers Cojedes, Portuguesa, and Pao. We worked there from the 13th to 15th and from the 17th to 23rd of October 2009. Every day, we looked for jaguar tracks while driving on a dirt road at the side of the group of eight paddocks that contained the cows and calves. A stream with forested banks flowed through the central paddock with the highest number of calves. Jaguars that killed a calf inside a paddock usually dragged the carcass across the road to the forest, leaving tracks and signs of dragging on the road. When we found jaguar tracks and signs of prey dragging, we followed them trying to locate the site where the prey was hidden. After locating a prey carcass, we examined it for signs of killing and consumption by jaguar and scavengers. Then, we set two Pix-Controller camera traps (PixController Inc., Export, PA, USA). We attempted to set the cameras at four prey sites; however, owing to technical problems with the cameras, we only managed to record jaguars at two sites, and only at one site did the cameras properly record jaguar behavior for the whole night.
During 9 days of our work, we found seven carcasses of calves killed by a jaguar. Six of them were found in the forest on the side of the central paddock with a stream with forested banks. Tracks found on the road indicated that all six calves were killed by the same female jaguar leading one cub. One prey was found on the side of another paddock, at a distance of about 1.6 km from the other six carcasses, and it was not clear if that prey was killed by the same jaguar. Only in one case did the jaguar kill two calves (Figure 1) on the same night. In all other cases, we found only one fresh prey. In most cases, the tracks found on the road were only those of the female, indicating that she was hunting alone. Tracks found closer to hidden car-casses were always of both – the female and the cub.All calves found were freshly killed and almost intact at their first localization. Three of them had clear teeth marks at the posterior part of the head, and in three others, the upper and back parts of the head (brain) and part of the neck were eaten. Remarkably, every kill was eviscerated and no intestines were found in its vicinity, suggesting that the jaguar had eaten them. Interestingly, in four carcasses we found only a small opening in the abdomen, but still all the intestines were removed. Most kills, except one that was hidden inside the paddock, were moved by the jaguar from the killing site to concealment at a distance of 50–80 m from the fence or 250–300 m from the central part of the paddock.
Our visits to the prey sites in the following days indicated that the jaguars came back to the site where the prey was hidden the next night after killing it and utilized the carcass only for one night, consuming most of it (in the case of four small newborn calves) or more than half of it (in the case of two bigger calves). Only in the case of the distant carcass, found far from the other six preys, the jaguars did not come back at all. The parts of carcass that were usually left were the legs, backbone, head or parts of it, and in the case of the two larger calves, the whole posterior part of the prey. After the jaguars left (usually around the early morning of the second day after killing), black vultures (Coragyps atratus Bechstein 1793) and foxes (Cerdocyon thous Linnaeus 1776) utilized the carcass. On the third day, the remains of the carcass became decayed and were covered with large numbers of insect larvae. Only in the case of two calves killed on the same night did the jaguars come back to eat the prey for two consecutive nights (up to the third night after killing).
During the continuous automatic video recording at the calf carcass on the night of 19th/20th October 2009 (the second night after killing that prey), the presence of jaguars was recorded from 18:45 to 04:54 (Figure 1). During that night, the jaguars utilized the carcass intermittently with the female appearing at the site five times and the cub six times (Table 1).
*This image is copyright of its original author
*This image is copyright of its original author
Continuous bouts of visits by the female lasted from 2 to 62 min (mean 18 min), and those of the cub from 1 to 50 min (mean 16 min). The total time that the female was present around the prey was 90 min, and for 68 min of that she was recorded to be eating. The cub was present for 94 min, eating the prey for 50 min. Most of the time, the female and the cub stayed at the kill site together (Figure 1); however, for 25% of the time, the cub was left alone and the female was recorded without the cub for 14% of the time. The majority of the jaguar activity at the kill site was foraging, with the female starting first by plucking hairs to gain access to the meat. An additional behavior recorded was play. The female spent 4% of time playing with the cub and the cub played 15% of the time in total, either with the mother or with objects such as the camera.The distribution and sequence of kills, the rate of their utilization by jaguars, and recorded tracks indicated a repet-itive pattern of behavior: (1) killing a calf inside the paddock close to the stream, which ensured better concealment; (2) dragging the carcass to concealment; (3) eviscerating the calf, eating the intestines, and leaving it concealed until the next night; (4) the next night, feeding on the carcass together with the cub in five to six short bouts; and (5) hunting for a new prey, while leaving the cub with the carcass. The recorded behavior of the female jaguar with one offspring can lead to the conclusion that she attempted to hunt a new prey every night over the short period of our study. This would give some maximum estimate of the kill rate equal to one calf per day. Based only on the six calves that were killed close to the central paddock and found by us over the period of 9 days, we can calculate that the minimum kill rate of that female was 0.67 kills/day or 1 kill/1.5 days.
The sequence of the female jaguar predatory behavior from killing through concealing and consuming recorded in our study has, in general, matched the pattern known in other large or medium-sized felids recorded for natural prey (Okarma et al. 1997, Sunquist and Sunquist 1989, 2002). However, our study documented a more detailed, repetitive sequence of female jaguar behavior while hunting for cattle. All components of this sequence seem to have highly adaptive significance for a female jaguar rearing cubs. It seems to be directed at ensuring continu-ous provision of food for offspring and for herself (killing and utilization of two different prey overlapping in time), avoiding fast decay (evisceration), ensuring safety from humans, and avoiding competition with scavengers (drag-ging the prey to concealment).
Among large carnivores, killing prey by direct perfo-ration of skull is unique for the jaguar and is a result of the jaguar’s extremely strong and powerful mandibles and canines (Meachen-Samuels and Van Valkenburgh 2009, Del Moral Sachetti et al. 2011). Prey evisceration by jaguars was recorded in several studies (Schaller and Vasconcelos 1978, Hoogesteijn and Mondolfi 1992, Craw-shaw and Quigley 2002). However, an interesting aspect of this behavior noticed in our study and not mentioned in the literature is the precise evisceration of prey through a small opening in the abdomen.The high kill rate of the female jaguar recorded by us can be partially explained by the fairly small body mass of newborn calves. In Hato Piñero, it is on average 35 kg, which is much less than the jaguar body mass (Scognamillo et al. 2003). Additionally, the fast rate of meat decay in Hato Piñero and intensive scavenging by vultures and foxes could have also been influencing the kill rate of that female. There was no indication that our presence had any important effect on her kill rate and killing behavior.
The high kill rate that we observed may also be explained as a temporal increase in hunting effort of the female jaguar in order to rear the cub. Similar increase has been documented for female lynx (Okarma et al. 1997). It should be emphasized, however, that it is difficult to draw conclusions based on our observations about the long-term kill rate of reproducing jaguar females or about the total effect of female jaguar predation over cattle populations. The kill rate of a radio-collared jaguar female with one cub reported by Cavalcanti and Gese (2010) in Pantanal was one large prey per 3.6 days. Only few authors have documented a kill rate by female jaguars equally high as in our study (Brock 1963, Almeida 1986).
Several factors may reduce the final predation impact of female jaguars on cattle. First, the number of reproducing females is limited by their territorial behavior. Accord-ing to Scognamillo et al. (2003) and Polisar et al. (2003), during their studies inside Hato Piñero, there were four adult females. Second, jaguar females reproduce usually every second year (Hoogesteijn and Mondolfi 1992). Finally, in developed Venezuelan ranches, the calving season, with high availability of newborn calves, is fairly short (90–120 days).
Some of the behavioral components of the jaguar female predation observed by us in Hato Piñero are pos-sible to modify in order to prevent high losses. Limiting accessibility of calves for jaguars by proper location of nurseries (especially locating them far from streams and forests), shortening of calving season, and electric fencing are among the most important preventing measures that have been also proposed by other authors (Quigley and Crawshaw 1992, Hoogesteijn et al. 1993, 2002, Michalski et al. 2006, Azevedo and Murray 2007, Hoogesteijn and Hoogesteijn 2010, Hoogesteijn and Hoogesteijn 2011).
The following 1 user Likes Balam's post:1 user Likes Balam's post • Rage2277
