page_title: Fat sand rat
section_title: Reproduction
hierarchical_section_title: Fat sand rat / Ecology / Reproduction
caption_attribution_description: עברית: פסמון אוכל מלוח קיפח, בסמוך לשדה בוקר English: Psammomys obesus, Sde Boker- israel.
context_page_description: The fat sand rat is a terrestrial mammal from the gerbil subfamily that is mostly found in North Africa and the Middle East, ranging from Mauritania to the Arabian Peninsula. This species usually lives in sandy deserts, but may also be found in rocky terrain or saline marsh areas. Fat sand rats are very selective in their diet, only eating stems and leaves of plants from the family Amaranthaceae, more commonly known as the amaranth family. The fat sand rat acquired its name due to the fact that when it is fed a typical rodent diet, it quickly becomes obese and develops diabetes. P. obesus has an average lifespan of 14 months in the wild and 3–4 years in captivity.
context_section_description: The fat sand rat breeds from autumn to early spring and produces litters usually consisting of one to eight pups, with average litter sizes increasing over the course of the breeding season. When mothers start lactating, their body energy increases but towards the end of the lactation period they begin to utilize stored energy instead of increasing body energy, resulting in a decrease in body mass. The growth rate of pups is maximized when the litter is small and the mother eats plants with a higher water content. The young disperse from their mother at about 5 weeks of age.
  
  The sexual activity of male fat sand rats is not affected by weather conditions, however there is a correlation between rainfall and the sexual activity of females, with more females being sexually active as the amount of rainfall increases. Reproductive strategies differ between the sexes, with females utilizing smaller ranges of space around their burrow with adequate food resources to provide for their young. Meanwhile, males occupy larger home ranges that overlap with multiple female ranges, creating the potential to mate with several females. Females initiate copulation, and have stereotypical behaviours for approaching males, squealing and turning to dig in and kick sand towards the male. After this display, the female will exhibit lordosis, and the male will mount the female over a series of copulations. Often, a female will lose interest quickly, and will threaten or act aggressively towards the male between mounts.
caption: Fat sand rat eating Atriplex halimus, Israel
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