A Study On Cheetahs Biology Essay

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Cheetahs were once common in South Central Asia to south West Asia, unfortunately after the nineteenth century is habitat has been very much reduced to central Iran and pockets in Africa (Charruau et al. 2011)Figure. Understanding the current habitat and distribution of Acinonys jubatus is fundamental for preserving and improving the survival of the species. Pettorelli et al., suggests that in order to study a cheetah territory one most take in to account the organism life history (Pettorelli et al. 2009). An individual age, sex, social status will be correlated to its range and habitat niche (Pettorelli et al. 2009). For example, males that form groups will have smaller habitats than males without a group or territory and females that roam around (Broomhall, 2004).

In Kruger National Park, cheetahs are found in woodland savannahs where the Thomson's gazelle forages (Broomhall et al. 2004; Hayward et al. 2006) and male cheetahs will often seek territories of high tree cover, since features like this attract females and are good for stalking prey and avoiding predators (Broomhall et al. 2004).

In a field study conducted by Broomhall, to determine the home range and habitat of the cheetah in the southern part of Kruger National Park, where the mean annual rain fall is between 400-800 mm (Shamrocks 2007). They used small radio collars on seven cheetahs, 3 males (M1, M2, and M3) and 4 females (F1, F2, F3, and F4) from 1987-1990, and divide the area of study in three different types of landscapes: tree savannah (on the center), semi-wooded savannah (to the west), and open savannah (to the east) (Broomhall et al. 2004).

During the study, they found that for both male and female cheetahs a large proportion of their home range is found in open savannahs, but females having a greater range in the Lebombo hills, where shrubs thicken. The range for males and females was determined to be 104-1800 km square in KNP. They also found that female cheetahs range and habitat is severely influenced by impala and gazelle herds, in both wet and dry seasons (Broomhall et al. 2004). Females will follow the herds, as they do not response to different vegetation gradients for activities, while males will hunt and rest in medium (20-60 cm) and small (0-20cm) grasses, but will not enter tall grasses (60 cm or higher). Therefore male cheetahs will often spend about 50% in median shrub habitats and 50% in open shrub habitats, while the females spend about 72% in median shrub habitats, 14% in dense shrub habitats, and 14% in open shrub habitats, as shown in figure 1 (Broomhall et al. 2004). Thus, cheetahs prefer and need an open habitat in woodland areas such in Kruger National Park, with the exception of females, since habitat is influenced by prey distribution.

In the Serengeti ecosystem a similar story, jet different is told by Petterelli. In her study analyzing the ecological niche factors of the Acynonix jubatus, she proclaims that the study in Kruger National Park was an attempt to understanding the habitat selection by the species, since their sample size was fairly small (n=7) (Pattorelli et al. 2009). In her study she used an Ecological Niche Factor Analysis (ENFA) approach, to understand the distribution of ecological variables (EGVs), between marginality, specialization, and tolerance for over 100 individuals. For marginality they look at the difference in variables used by the cheetahs and the variables found within the area of study. Specialization was found in the ratios between different conditions used by individuals and total conditions available in the area of study, while tolerance was the inverse of specialization.

Observation of cheetahs where made, using binoculars and unique fur patterns, to prevent duplication of results. They used statistical analysis and Biomapper 3.1 to perform the ENFAs (table). They tested for three ecological niche factores: 1) females observed in the area of study, 2) males with territories, and 3) males without territories. Values ENFAs vary from negative to positive numbers. Negative numbers mean a low association, while positive values mean a strong association.

The marginality for females cheetahs was 1.04, 1.13 for males with no territories, and 1.08 for males that had territories. The tolerance was found to be highest for females at .56, .44 for males with territories, and with a tolerance of .31 were cheetahs without territories (Pettorelli et al. 2009).

During the study they found that females and males do not use different habitats, despite age and gender differences, or whether they had territories or not. Their habitat use is correlated to the use of kopjes (rocks that provided a slight elevation over the plains), rivers, streams, and showed a low correlation with heavy tree cover, mountainous terrains, lakes, and humans (Pattorelli et al. 2009), with the exception of Botswana populations (Selebatso et al. 2008).

The results suggested that cheetahs, whether in territorial coalition or single and despite age and gender difference, most individuals are highly selective of their habitat and all avoided similar if not the same habitats that are not suitable, such as high cover. In fact all required or selected habitats that could offer high mobility.

Both studies (KNP and Serengeti) showed that the Acynonix jubatus habitat requires a large portion of open grass land, but in Broomhall studied female cheetahs required some amount of tree cover and males did not (Broomhall et al. 2004). In the Serengeti, Pattorelli showed that cheetahs avoid areas with dense tree cover, whether their male of female (Pattorelli et al. 2009). However, Pattorelli method was based of observations, thus the sampling in dense vegetation could have been difficult generating poor results, even though sample numbers are greater than Broomhall radio collar method, which provided an accurate location of individuals.

The studies, showed slight differences in environmental requirements of the cheetahs, but perhaps the slight differences are due to different environmental forces in both locations. In both experiments they did not took into an account the cheetahs' dietary components. Perhaps cheetahs in KNP are feeding on ungulates found in denser tree terrains, while in the Serengeti they are feeding on ungulates found in open grass lands (Hayward et al. 2006), or simply they are adapted to different environments that yield greater survival.

In Namibian farmlands, 41 cheetahs (26 males and 15 females) were tag with radio collars from 1993-2000 and found a mean home range of 1651 Km square, but some individual could have ranges less than 300 km square. Home range and habitat was scattered through sparse bush to thick bush, since diet composed mostly of ungulates found in all those habitats (Figure) (Marker et al. 2007). During the study, the cheetah's age and gender were taken into account and found no significant variation between ranges or habitat. The range through the year did not changed in size, even during dry and raining seasons, but simply shift a few kilometers. They also looked at overlapping ranges throughout the year, but not a significant amount was detected. The overlapping was in averaged 15% of home range by both males and females (figure) (Marker et al. 2007), suggesting that social interference was minimal or avoided by individuals.

Marker takes into account all if not all factors in the studies made in KNP and the SNP, with a big sample size and a precise method all recording locations of individuals. He also takes into account the cheetah's dietary consumption in both dry and rain seasons, making his data more reliable than KNO and SNP data.

The large home ranges and inconsistent environments of the cheetahs are probably essential for the survival in the wild. Hence, mobility is crucial and encounters with other predators is highly probable (Pattorelli et al. 2009), leading the cheetah to prey on mostly on small ungulates before higher rank predators take over their food.

In the wild cheetahs' are often avoiding large prey, such as buffalo, zebras, rhinoceros, etc… They go after small to median ungulates of 23-57 Kg, but prefer prey in the range of 27 kg, such as gazelles, impalas, and blesbuk (table) (Hayward et al. 2006). In a study perform in Kenya, Namibia, Tanzania, Zambia, Zimbabwe and South Africa from 1956 to 2005 by Hayward et al. (2006); they look at the dietary composition of the cheetah by observations of 3909 kills throughout the countries. They observed that the cheetahs preferred weak or young mammals that were easier to catch, therefore reducing the probability of injury and death by predation of larger predators, such as lions and hyenas. Ultimately avoidance of lions and hyenas is crucial for avoiding kleptoparasitism and death.

The dietary composition is perhaps based on their morphological body structure. Their unique long, slim, and light body, along with their long tail used for balance, allows them to exceed speed of over 100 Km/hr to maximize hunting success, but as a trade off they lack musculature and body size to defend against other predators and include lager game in their diet. Thus, the cheetah hunting success depends on capturing small to medium game.

The cheetah uses quick short bursts to catch prey, mainly in open grasslands. Their acceleration is quick; they can reach 100 km per hour in only a few seconds (Heyward et al. 2006). Because of their agility while sprinting, they can make fast turns. They are able to capture prey that no other predators in the savannah are able to hunt, since they are sprinters and not long-distance runners. They are easily tired after a short distance burst, usually after 70 meters into the chase (Shorrocks 2007). The cheetah's core temperature can rise up to 40 degrees Celsius during a chase and their muscles start to fatigue.

But before all the sprinting, the cheetah must get close to the prey, since they fatigue quickly. Using their camouflage to minimize detection, they slowly approach the herd, looking for the weakest member of the herd. Once they have attacked the ungulate, they go for the throat to suffocate and reduce panic responses emitted by the hoofed animal. This tactic reduced kleptoparasitism by avoiding other predators to hear the crying mammal (Marker et al. 2008).

The cheetah has a disadvantage among other predator when it comes to hunting, because unlike social predators cheetahs tend to avoid other individuals. Unless a small group of brothers form a coalition, but not enough evidence has been done in this area to prove that cheetah coalitions have higher hunting success rates than solitary cheetahs. In general their hunting success ranges from 37-70%, but about 15% of their kills are stolen by lions and hyenas (Shorrocks 2007).

Parental care is quite common among placental mammals and it has been observed that offspring survival is heavily correlated to the maturity of the parents and life histories (Pettorelli et al. 2007).