2 to 4 days Click to see full answer. Just so, how long does it take for a rat to starve to death?The length of time it takes for a dead rat to decompose varies, and is largely determined by the ambient temperature humidity levels. 1/30/2018 · This is what I learnt from having a pet hamster (another type of rodent):— * A hamster will starve to death without food for around 4–5 days.Subsequently, question is, how often do rats need water? Like mice, rats will live in freezers, feeding only on frozen food. Rats eat so much that one rat can leave behind 25,000 droppings per year. The rat’s main constraint is that it cannot go long without water unless its diet supplies enough. Rats need up to one ounce of water every day. Correspondingly, how long can pet rats go without food? two weeks Can rats survive in water?Rats have incredible stamina—they can tread water for three days straight! And they can hold their breath underwater for up to three minutes. This aquatic proficiency is the very reason rats became global travelers.