Reproduction
Naked mole rats are in the class Mammalia, meaning they give birth to live young. This also means that they undergo sexual reproduction; a naked mole rat typically becomes sexually mature at 1 year old (Atlanta Zoo, 2012). However, naked mole rats are said to be a eusocial mammal, one of two mammals that live this way (San Diego Zoo, 2012). The term eusocial means that only one female in the colony reproduces, and the rest are workers. The typical naked mole rat colony consists of about 70-80 members, but can range anywhere from 20-300 (Smithsonian National Zoological Park, 2012). All of the colony members are workers except for the queen, and one to three males whom the queen chooses to mate with (Cimons, 2010). Typically, the gestation period for naked mole rats is 70 days, and the litter size can vary greatly from 12-27 pups. Unlike other mammals, the time between pregnancies can be quite short. A naked mole rat queen is capable of producing a new litter every 80 days. With this short turnover period, she is able to produce approximately 5 litters per year. An adult naked mole rat usually weighs somewhere around 30-70 grams (Smithsonian National Zoological Park, 2012), meaning their pups are extremely tiny at birth, weighing only around 2 grams (Rosamond Gifford Zoo, 2006). To put this small size in perspective, 20 U.S nickels have a mass of about 5 grams, so these pups weigh approximately the same as 8 U.S nickels. Naked mole rat queens display one very interesting feature. When they first become queen, they are capable of lengthening their bodies, increasing the space between their ribs, in order to be able to carry a larger litter size and still fit through the tunnels (Rosamond Gifford Zoo, 2006).