Fat Sand Mouse

Fat Sand Mouse

Sand rat

Psammomys obesus
Population size
Life Span
14 mos-4 yrs
125-208 g
130-185 mm

The Fat sand rat is a gerbil species, endemic to desert areas, where it maintains a usual rodent diet, primarily consisting of leaves. This species was accidentally found in Egypt by the US Naval Medical Research Unit. In spite of the common name, this heavy-built rodent is not a rat. As a matter of fact, the sand rat is so called due to occurring on the sandy beaches of the Nile Delta, where it has been trapped. Meanwhile, they are called 'fat rats' because of their bulky appearance, which is more prominent in mature males. Females of this species are distinguished by leaner body as well as agility.


The Fat sand rats are distributed throughout North Africa and the Arabian Peninsula. Their African range extends eastwards from Mauritania to Egypt and Sudan. As ground-dwelling rodents, they generally occur in sandy deserts. Other suitable habitats include rocky terrain, saline-marsh areas and loess plains.

Climate zones

Habits and Lifestyle

The Fat sand rats are solitary and diurnal animals. Their daytime activity largely depends on season and temperature above the ground. During the winter months, the peak activity occurs in the midday, lasting for around 5 hours. Coming out of their dwellings, these rodents spend their time sunbathing, flattening their body as well as absorbing heat by outstretching their legs. Throughout the summer months, activity usually takes place in the early morning and afternoon. During this period, the rodents try to escape scorching midday sun. In areas where the night temperature is warm enough, they may also exhibit some activity during the nighttime hours. Communication is generally made by foot drumming as well as vocalizations such as high-pitched squeaks, although the purpose of these types of communication is unknown. However, these high-pitched squeaks are believed to serve as an alert against when threatened.

Diet and Nutrition

The diet of these herbivores (folivores) rodents generally consists of leaves of various succulent plants. They are known to especially favor salt bushes of the Chenopodiaceae family, supplementing this diet with barley and other grains.

Mating Habits

24 days
1-7 pups
3 weeks
pup, pinkie, kit

The reproductive system of this species is insufficiently explored, although the dominant males are known to have considerably larger territories that overlap with these of multiple females. Hence, the Fat sand rats may have a polygynous mating system, where one male mates with a number of females. Breeding occurs from December to April. Gestation period lasts for 24 days, yielding a litter of 1 - 7 babies. Females are able to produce 2 - 4 litter during each season. Newborn rats are completely hairless. They come with closed eyes that open at 1 week old. The young are weaned by 3 weeks old. The age of sexual maturity is 4 months old for males and 3 - 3.5 months old for females.


Population threats

Currently, the population of these animals as a whole is not threatened.

Population number

According to IUCN, the Fat sand rat is common and widespread throughout its range but no overall population estimate is available. Today, this species’ numbers are stable and it is classified as Least Concern (LC) on the IUCN Red List.

Ecological niche

Fat sand rats may have an impact on the populations of the bushes they consume. In addition, they are an important prey for the local predators.

Fun Facts for Kids

  • When feeling danger, Fat sand rats usually sit up on their hind limbs and observe surroundings to detect the threat. When alarmed, they flee to their burrows.
  • When eating, these rodents hold their meal with one 'hand'. Before consuming leaves, Fat sand rats wipe them. They also comb their fur with their front legs.
  • Sand rats can live without drinking water and consume only salty plants, comprising very little amount of moisture. This is due to their efficient kidneys, which produce urine that is up to 18 times as concentrated as that of humans.
  • Rats are known for their curious nature. However, these animals are extremely cautious, typically fleeing from danger rather than directly facing it.
  • Rats are very clean creatures. They spend a lot of time daily cleaning and grooming themselves and each other.
  • Rats have very little water requirements. They can survive without water for even longer periods of time than camels.
  • The multifunctional tail of this rodent is used in keeping balance, communication as well as controlling the body temperature.
  • In Indian tradition, rats are believed to be the vehicle of Lord Ganesh. Moreover, these animals are worshipped at the Karni Devi Temple, fed with grain and milk by priests and pilgrims of the temple.


1. Fat Sand Rat Wikipedia article - https://en.wikipedia.org/wiki/Fat_sand_rat
2. Fat Sand Rat on The IUCN Red List site - http://www.iucnredlist.org/details/18418/0

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