The Patagonian mara Dolichotis patagonum is a relatively large rodent in the mara genus Dolichotis. This herbivorous , somewhat rabbit -like animal is found in open and semiopen habitats in Argentina , including large parts of Patagonia. It is monogamous , but often breeds in warrens shared by several pairs. The Patagonian mara resembles a jackrabbit. Its hind limbs are longer and more muscular than its fore limbs and it has a longer radius than humerus. The fore feet have four digits while the hind feet have three digits.
|Published (Last):||9 September 2009|
|PDF File Size:||5.36 Mb|
|ePub File Size:||3.89 Mb|
|Price:||Free* [*Free Regsitration Required]|
Campos, et al. Patagonian maras live only in the arid central and southern regions of Argentina. Generally classified as desert, this area exhibits a wide range of distinct microhabitats ranging from sandy plains to thorny shrubland steppes.
Rainfall is extremely unpredictable and there are huge shifts in precipitation and floral composition between wet and dry seasons. The area is quite warm, with average temperatures in the summer usually around 20 degrees Celsius and winter temperatures rarely dropping below freezing. Generally, Patagonian maras prefer to build dens in open habitat dominated by grasses and other low-growing plants.
Though it dens in areas that are densely vegetated, they visually monitor for predators, which is less effective in more closed habitats. Large settlements of Patagonian maras have been observed on and around sheep ranches, most likely due to their similar habitat preferences. Baldi, ; Campos, et al. Dolichotis patagonum is the second largest member of the family Caviidae. One study reported average weights of males and females as 7.
However, most accounts report that males are larger than females. Length ranges from to mm with an average of mm. They can be distinguished from other members of Caviidae by their large size, long rabbit-like ears Dolichotis literally means "long ear" , and short, nearly hairless tail which it holds close to the body.
Unlike other cavies, which have anal glands anterior to the anus, the anal glands of D. It has short, grizzly gray fur , with a large, conspicuous patch of white on the rump. Midway up the rump a sharply contrasting area of black occurs, which quickly fades to gray.
The venter is white, with patches of rusty orange fur on the chin, cheeks, and flanks. Two subspecies are recognized: Dolichotis patagonum centricola and Dolichotis patagonum patagonum , which are distinguished based on geographic location and fur coloration.
Much like ungulates, Dolichotis patagonum has elongated metapodials in its hindlegs as a modification for fast and efficient running. Forelegs are significantly longer than in most other rodents , and both the hind- and forefeet are small with hoof-like claws. Forefeet have four digits while hindfeet have three, and all digits have a claw.
The elbow lies relatively high on the forelimb as the radius is longer than the humerus. Dolichotis patagonum is strongly monogamous, and male-female pairs usually bond for life. The pair-bond is maintained mainly by the efforts of the male, who follows and guards the female wherever she goes.
To mark her as his territory, he urinates on her, spreads anal gland secretions around her and fiercely defends her from rival males. Males have been observed fighting, but there has never been a documented case of mate stealing.
Because estrus occurs once every 3 to 4 months and lasts for just half an hour, monogamy is advantageous, as spending all his time with one female assures a male that he does not miss his chance to breed.
Monogamy may have also arisen as a response to the patchy and sparsely distributed food resources of the region.
Since this sort of resource distribution is likely to result in a very scattered distribution of females, a male has the highest chance of successful breeding by finding one female and remaining with her.
Another benefit to pair-bonds is that females are able to invest additional time and attention to caring for her young, relying on the male to watch for predators. Monogamy increases the males reproductive success both by lowering the death rate of his own offspring and increasing the longevity of his mate, allowing him more chances to breed.
Female Patagonian maras are sexually mature by 8 months of age. Estrus occurs once every 3 or 4 months and lasts only about half an hour. This extremely short estrous cycle is very unusual and most likely played a part in the evolution of monogamy in this species. Females in captivity often conceive shortly after parturition and can give birth to 3 or 4 litters per year, however, in the wild only one litter per year is produced.
Litters range in size from 1 to 3 pups, with average litters containing 2. Rarely, a few females may have a second litter around January, but the majority of pups are born between mid August and late December. There is a large pulse of births between mid September and late October, with almost two thirds of pups being born during this time period. Gestation lasts an average of days in the wild. Females have 6 or 8 teats and nurse 1 or 2 pups at a time. On rare occasions females have been seen nursing up to 4 pups, suggesting occasional milk stealing by unrelated pups.
It is thought that females recognize their young mainly by size, so pups of similar size to a female's own pups may have greater milk stealing success. Females also recognize their young by sound and scent cues. Occasionally, orphaned pups may be "adopted" by another female and allowed to suckle.
However, females usually aggressively reject interloping pups by lunging, chasing, biting and shaking, or throwing them away from her. Some pups make frequent attempts to steal milk and many have tattered and damaged ears from these fierce rejections.
Nursing bouts last for about half an hour and adult visits to the den usually last about an hour. Pups are usually nursed for about 75 to 78 days, which is unusually long compared to other rodents. Like many ungulates, Dolichotis patagonum exhibits the "hider" strategy through the first part of their lives, staying close to the burrow and hiding at the signal from an adult sentry.
As pups mature, they go through a "follower" phase where they trail behind their parents on foraging expeditions farther away from the burrow. Most young disperse at the time of weaning, however some stay with their parents until the next breeding season.
Though members of this species spend most of the year associating strictly as male-female pairs, when pups are born Dolichotis patagonum gathers in large groups around large warren "settlements" and raise young in communal creches.
Each communal den has on average 4. Since males aggressively guard their mates, only one pair at a time is present at the den. Males contribute very little in terms of direct parental care. They rarely interact with small pups, and interactions with large pups is limited to sitting or foraging nearby.
However, males spend the majority of their time watching for predators, which significantly lowers predation risk faced by his offspring and mate. Taber and Macdonald, a ; Taber and Macdonald, b. Little information could be found on the lifespan of wild or captive mara. Patagonian maras are diurnal, cursorial rodents.
For most of the year, they travel in male-female bonded pairs, and very rarely are there more than three maras spotted together at one time. Male-female pairs travel during the day, spending more time grazing in rich patches than sparse ones. Patagonian maras form large groups called settlements, which consists of a collection of dens or warrens.
Some warrens are small and widely spaced and used by just a single pair, while some large dens can be shared by up to 29 pairs. Local population densities may rise dramatically during this time, and groups of up to 70 maras have been observed. Females spend much more time with offspring than males, and males spend much more time watching for predators than females.
Due to the large physiological investment that females make in reproduction, females spend more time feeding than males during this time as well. Males fiercely defend their mates. As a result, typically only one pair at a time can occupy the den. Breeding pairs "take turns" visiting the den for approximately one hour at a time to nurse their young. Taber and Macdonald, a.
The home range of Patagonian maras drifts continuously, most likely as a result of the patchily distributed and widely spaced food resources present in the region. They eat only the very tips of grass blades, so food resources are exhausted very quickly. Once a resource patch has been exhausted, it takes up to four months to be completely renewed. A single, static territory large enough to support a pair of maras for a year would likely be too large for a pair of maras to defend against inter- and intraspecific competitors.
Furthermore, communal denning would be nearly impossible, as it is unlikely that ranges of sufficient size would overlap around a communal warren. Therefore, small, drifting ranges are favorable, allowing Patagonian maras to be near the communal warren during pupping season while also freeing it from the demanding task of defending large territories. Their home ranges are between Dolichotis patagonum prefers open habitats. Similar to ungulates, D. Also similar to some ungulates, Patagonian maras exhibit stotting behavior, which is characterized by a bounding gait that advertises strength and speed and discourages a long and costly chase by the predator.
Like many rodents, Dolichotis patagonum has a pair of anal scent glands. Males are frequently observed anal dragging, which results in a unique looking scent mark. Anal gland secretions play a major role in the mobile territory that males form around their mate.
It is not know whether D. The range of Dolichotis patagonum encompasses a variety of habitats from desert to shrubland steppe. A strict herbivore, D. Despite the fact that most plant biomass in the region consists of forbs and shrubs, D. Most grasses consumed are in the genus Pappophorum. In total, D. This may help offset the unpredictability of rainfall throughout the range of D. Sombra and Mangione, Near the central part of its range, evidence suggests that the grass genera Poa and Panicum make up the bulk of Dolichotis patagonum 's diet, followed by Stipa and Bromus.
Open-shrubland inhabitants also forage on Doli chotis patagonum and grassland inhabitants consume Lycium. Dolichotis patagonum in sandy grasslands and lithosol shrublands prefer Prosopis. These habitat specific differences display the dietary flexibility of this herbivore.
During droughts, Dolichotis patagonum adjusts its diet to include more moisture-rich plants. Puig, et al.