<P> In captivity, females become sexually mature at two months of age . The ovarian follicle forms about 16 days prior to the birth of the offspring . After mating, female hamsters typically have larger uteri, ovaries, and adrenal glands compared to females which live alone, with other females or those that have not mated . The females and males may fight each other when getting to know their partner . Also, these females have a shorter gestation period, around four to five days . </P> <P> In captivity, only Campbell's dwarf hamsters and Djungarian hamsters are able to interbreed and produce live offspring or hybrids . Although hybrids make suitable pets, the breeding of hybrids and cloning can cause health problems, due to inherited diseases . Because genetic information can be very similar, genetic health problems or vulnerabilities can easily be inherited by the offspring . The widespread breeding and distribution of hybrids could threaten the existence of both pure species and subspecies of the ecosystem . This could ultimately lead to the extinction of the subspecies . Each litter becomes smaller as more generations are produced and the young commonly begin to inherit many congenital problems . </P> <P> The two species of Phodopus hamsters (P. sungorus and P. campbelli) have the same number of chromosomes, and the chromosomes are similar in terms of size and morphology . However, several chromosomes show structural differences in the location and size of C - heterochromatin blocks . In nature, the two species do not meet, but will mate and produce offspring in captivity . However, both reciprocal crosses produce sterile hybrid males and females with decreased fertility . There is a clear effect in which types the parents are . The cross P. sungorus male x P. campbelli female will have embryos that grow normally, like both parent species . But the cross between P. campbelli male x P. sungorus female result in overgrowth, leading to embryonic death . </P> <P> Campbell's dwarf hamsters inhabit burrows in the steppes and semideserts of central Asia, the Altai mountains, autonomous areas of Tuva, and the Hebei province in northeastern China . A burrow can contain four to six horizontal and vertical tunnels . The tunnels leading to the nesting area can be as deep as 1 m (3 ft 3 in) below the ground, but are usually 20--30 cm (7.9--11.8 in) deep . The burrows are lined with either dry grass or sheep's wool . They may sometimes share burrows with Daurian pikas, but only in the steppes and semideserts of northern Manchuria . In parts of Mongolia, the hamsters may also share burrows with species of Meriones to save them from digging their own . In Tuva, Campbell's dwarf hamsters have been found living with other hamsters, such as the Chinese striped hamster, the Roborovski hamster, and the long - tailed dwarf hamster . The diets of the three types of hamsters are different to avoid fighting over the same type of food, which is why they live together . </P>

Where do dwarf hamsters live in the wild